Question: How much impact do masks have on preventing the spread of the COVID-19?

Title: Who is wearing a mask? Gender-, age-, and location-related differences during the COVID-19 pandemic Content: Masks are an effective tool in combatting the spread of COVID-19 but wearing them remains controversial and has not been studied in the United States. To understand the demographics of mask wearers in the US, we observed shoppers (n = 5517) entering retail stores. 41.5% of the observed sample wore a mask. The odds of an individual wearing a mask increased significantly with age, and was also 1.5x greater for females than males. Additionally, the odds of observing a mask on an urban or suburban shopper were ~4x that for rural areas. Thus, gender, age, and location factor into whether American shoppers wear a mask or face covering. Regardless, all demographics wore masks at substantially lesser rates than required to stop the spread of COVID-19.

Title: Brief research report: Bidirectional impact of imperfect mask use on reproduction number of COVID-19: A next generation matrix approach() Content: The use of masks as a means of reducing transmission of COVID-19 outside healthcare settings has proved controversial. Masks are thought to have two modes of effect: they prevent infection with COVID-19 in wearers; and prevent transmission by individuals with subclinical infection. We used a simple next-generation matrix approach to estimate the conditions under which masks would reduce the reproduction number of COVID-19 under a threshold of 1. Our model takes into account the possibility of assortative mixing, where mask users interact preferentially with other mask users. We make 3 key observations: 1. Masks, even with suboptimal efficacy in both prevention of acquisition and transmission of infection, could substantially decrease the reproduction number for COVID-19 if widely used. 2. Widespread masking may be sufficient to suppress epidemics where R has been brought close to 1 via other measures (e.g., distancing). 3. “Assortment” within populations (the tendency for interactions between masked individuals to be more likely than interactions between masked and unmasked individuals) would rapidly erode the impact of masks. As such, mask uptake needs to be fairly universal to have an effect. This simple model suggests that widespread uptake of masking could be determinative in suppressing COVID-19 epidemics in regions with R(t) at or near 1.

Title: Impact of population mask wearing on Covid-19 post lockdown Content: COVID-19, caused by SARS-CoV2 is a rapidly spreading global pandemic. Although precise transmission routes and dynamics are unknown, SARS-CoV2 is thought primarily to spread via contagious respiratory droplets. Unlike with SARS-CoV, maximal viral shedding occurs in the early phase of illness, and this is supported by models that suggest 40-80% of transmission events occur from pre- and asymptomatic individuals. One widely-discussed strategy to limit transmission of SARS-CoV2, particularly from presymptomatic individuals, has been population-level wearing of masks. Modelling for pandemic influenza suggests some benefit in reducing total numbers infected with even 50% mask-use. COVID-19 has a higher hospitalization and mortality rate than influenza, and the impacts on these parameters, and critically, at what point in the pandemic trajectory mask-use might exert maximal benefit are completely unknown. We derived a simplified SIR model to investigate the effects of near-universal mask-use on COVID-19 assuming 8 or 16% mask efficacy. We decided to model, in particular, the impact of masks on numbers of critically-ill patients and cumulative mortality, since these are parameters that are likely to have the most severe consequences in the COVID-19 pandemic. Whereas mask use had a relatively minor benefit on critical-care and mortality rates when transmissibility (Reff) was high, the reduction on deaths was dramatic as the effective R approached 1, as might be expected after aggressive social-distancing measures such as wide-spread lockdowns. One major concern with COVID-19 is its potential to overwhelm healthcare infrastructures, even in resource-rich settings, with one third of hospitalized patients requiring critical-care. We incorporated this into our model, increasing death rates for when critical-care resources have been exhausted. Our simple model shows that modest efficacy of masks could avert substantial mortality in this scenario. Importantly, the effects on mortality became hyper-sensitive to mask-wearing as the effective R approaches 1, i.e. near the tipping point of when the infection trajectory is expected to revert to exponential growth, as would be expected after effective lockdown. Our model suggests that mask-wearing might exert maximal benefit as nations plan their post-lockdown strategies and suggests that mask-wearing should be included in further more sophisticated models of the current pandemic.

Title: Face mask use in the general population and optimal resource allocation during the COVID-19 pandemic Content: The ongoing novel coronavirus disease (COVID-19) pandemic has rapidly spread in early 2020, causing tens of thousands of deaths, over a million cases and widespread socioeconomic disruption. With no vaccine available and numerous national healthcare systems reaching or exceeding capacity, interventions to limit transmission are urgently needed. While there is broad agreement that travel restrictions and closure of non-essential businesses and schools are beneficial in limiting local and regional spread, recommendations around the use of face masks for the general population are less consistent internationally. In this study, we examined the role of face masks in mitigating the spread of COVID-19 in the general population, using epidemic models to estimate the total reduction of infections and deaths under various scenarios. In particular, we examined the optimal deployment of face masks when resources are limited, and explored a range of supply and demand dynamics. We found that face masks, even with a limited protective effect, can reduce infections and deaths, and can delay the peak time of the epidemic. We consistently found that a random distribution of masks in the population was a suboptimal strategy when resources were limited. Prioritizing coverage among the elderly was more beneficial, while allocating a proportion of available resources for diagnosed infected cases provided further mitigation under a range of scenarios. In summary, face mask use, particularly for a pathogen with relatively common asymptomatic carriage, can effectively provide some mitigation of transmission, while balancing provision between vulnerable healthy persons and symptomatic persons can optimize mitigation efforts when resources are limited.

Title: To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic Content: Face mask use by the general public for limiting the spread of the COVID-19 pandemic is controversial, though increasingly recommended, and the potential of this intervention is not well understood. We develop a compartmental model for assessing the community-wide impact of mask use by the general, asymptomatic public, a portion of which may be asymptomatically infectious. Model simulations, using data relevant to COVID-19 dynamics in the US states of New York and Washington, suggest that broad adoption of even relatively ineffective face masks may meaningfully reduce community transmission of COVID-19 and decrease peak hospitalizations and deaths. Moreover, mask use decreases the effective transmission rate in nearly linear proportion to the product of mask effectiveness (as a fraction of potentially infectious contacts blocked) and coverage rate (as a fraction of the general population), while the impact on epidemiologic outcomes (death, hospitalizations) is highly nonlinear, indicating masks could synergize with other non-pharmaceutical measures. Notably, masks are found to be useful with respect to both preventing illness in healthy persons and preventing asymptomatic transmission. Hypothetical mask adoption scenarios, for Washington and New York state, suggest that immediate near universal (80%) adoption of moderately (50%) effective masks could prevent on the order of 17–45% of projected deaths over two months in New York, while decreasing the peak daily death rate by 34–58%, absent other changes in epidemic dynamics. Even very weak masks (20% effective) can still be useful if the underlying transmission rate is relatively low or decreasing: In Washington, where baseline transmission is much less intense, 80% adoption of such masks could reduce mortality by 24–65% (and peak deaths 15–69%), compared to 2–9% mortality reduction in New York (peak death reduction 9–18%). Our results suggest use of face masks by the general public is potentially of high value in curtailing community transmission and the burden of the pandemic. The community-wide benefits are likely to be greatest when face masks are used in conjunction with other non-pharmaceutical practices (such as social-distancing), and when adoption is nearly universal (nation-wide) and compliance is high.

Title: To mask or not to mask: Modeling the potential for face mask use by the general public to curtail the COVID-19 pandemic Content: Face mask use by the general public for limiting the spread of the COVID-19 pandemic is controversial, though increasingly recommended, and the potential of this intervention is not well understood. We develop a compartmental model for assessing the community-wide impact of mask use by the general, asymptomatic public, a portion of which may be asymptomatically infectious. Model simulations, using data relevant to COVID-19 dynamics in the US states of New York and Washington, suggest that broad adoption of even relatively ineffective face masks may meaningfully reduce community transmission of COVID-19 and decrease peak hospitalizations and deaths. Moreover, mask use decreases the effective transmission rate in nearly linear proportion to the product of mask effectiveness (as a fraction of potentially infectious contacts blocked) and coverage rate (as a fraction of the general population), while the impact on epidemiologic outcomes (death, hospitalizations) is highly nonlinear, indicating masks could synergize with other non-pharmaceutical measures. Notably, masks are found to be useful with respect to both preventing illness in healthy persons and preventing asymptomatic transmission. Hypothetical mask adoption scenarios, for Washington and New York state, suggest that immediate near universal (80%) adoption of moderately (50%) effective masks could prevent on the order of 17--45% of projected deaths over two months in New York, while decreasing the peak daily death rate by 34--58%, absent other changes in epidemic dynamics. Even very weak masks (20% effective) can still be useful if the underlying transmission rate is relatively low or decreasing: In Washington, where baseline transmission is much less intense, 80% adoption of such masks could reduce mortality by 24--65% (and peak deaths 15--69%), compared to 2--9% mortality reduction in New York (peak death reduction 9--18%). Our results suggest use of face masks by the general public is potentially of high value in curtailing community transmission and the burden of the pandemic. The community-wide benefits are likely to be greatest when face masks are used in conjunction with other non-pharmaceutical practices (such as social-distancing), and when adoption is nearly universal (nation-wide) and compliance is high.

Title: Mask use during COVID-19: A risk adjusted strategy() Content: In the context of Coronavirus Disease (2019) (COVID-19) cases globally, there is a lack of consensus across cultures on whether wearing face masks is an effective physical intervention against disease transmission. This study 1) illustrates transmission routes of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2); 2) addresses controversies surrounding the mask from perspectives of attitude, effectiveness, and necessity of wearing the mask with evidence that the use of mask would effectively interrupt the transmission of infectious diseases in both hospital settings and community settings; and 3) provides suggestion that the public should wear the mask during COVID-19 pandemic according to local context. To achieve this goal, government should establish a risk adjusted strategy of mask use to scientifically publicize the use of masks, guarantee sufficient supply of masks, and cooperate for reducing health resources inequities.

Title: Mask use during COVID-19: A risk adjusted strategy Content: In the context of Coronavirus Disease (2019) (COVID-19) cases globally, there is a lack of consensus across cultures on whether wearing face masks is an effective physical intervention against disease transmission. This study 1) illustrates transmission routes of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2); 2) addresses controversies surrounding the mask from perspectives of attitude, effectiveness, and necessity of wearing the mask with evidence that the use of mask would effectively interrupt the transmission of infectious diseases in both hospital settings and community settings; and 3) provides suggestion that the public should wear the mask during COVID-19 pandemic according to local context. To achieve this goal, government should establish a risk adjusted strategy of mask use to scientifically publicize the use of masks, guarantee sufficient supply of masks, and cooperate for reducing health resources inequities.

Title: Efficacy of face mask in preventing respiratory virus transmission: a systematic review and meta-analysis Content: Background: Conflicting recommendations exist related to whether masks have a protective effect on the spread of respiratory viruses. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was consulted to report this systematic review. Relevant articles were retrieved from PubMed, Web of Science, ScienceDirect, Cochrane Library, and Chinese National Knowledge Infrastructure (CNKI), VIP (Chinese) database. Results: A total of 21 studies met our inclusion criteria. Meta-analyses suggest that mask use provided a significant protective effect (OR = 0.35 and 95% CI = 0.24-0.51). Use of masks by healthcare workers (HCWs) and non-healthcare workers (Non-HCWs) can reduce the risk of respiratory virus infection by 80% (OR = 0.20, 95% CI = 0.11-0.37) and 47% (OR = 0.53, 95% CI = 0.36-0.79). The protective effect of wearing masks in Asia (OR = 0.31) appeared to be higher than that of Western countries (OR = 0.45). Masks had a protective effect against influenza viruses (OR = 0.55), SARS (OR = 0.26), and SARS-CoV-2 (OR = 0.04). In the subgroups based on different study designs, protective effects of wearing mask were significant in cluster randomized trials, case-control studies and retrospective studies. Conclusions: This study adds additional evidence of the enhanced protective value of masks, we stress that the use masks serve as an adjunctive method regarding the COVID-19 outbreak.

Title: Efficacy of face mask in preventing respiratory virus transmission: A systematic review and meta-analysis Content: BACKGROUND: Conflicting recommendations exist related to whether masks have a protective effect on the spread of respiratory viruses. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was consulted to report this systematic review. Relevant articles were retrieved from PubMed, Web of Science, ScienceDirect, Cochrane Library, and Chinese National Knowledge Infrastructure (CNKI), VIP (Chinese) database. RESULTS: A total of 21 studies met our inclusion criteria. Meta-analyses suggest that mask use provided a significant protective effect (OR = 0.35 and 95% CI = 0.24-0.51). Use of masks by healthcare workers (HCWs) and non-healthcare workers (Non-HCWs) can reduce the risk of respiratory virus infection by 80% (OR = 0.20, 95% CI = 0.11-0.37) and 47% (OR = 0.53, 95% CI = 0.36-0.79). The protective effect of wearing masks in Asia (OR = 0.31) appeared to be higher than that of Western countries (OR = 0.45). Masks had a protective effect against influenza viruses (OR = 0.55), SARS (OR = 0.26), and SARS-CoV-2 (OR = 0.04). In the subgroups based on different study designs, protective effects of wearing mask were significant in cluster randomized trials and observational studies. CONCLUSIONS: This study adds additional evidence of the enhanced protective value of masks, we stress that the use masks serve as an adjunctive method regarding the COVID-19 outbreak.

Title: Efficacy of face mask in preventing respiratory virus transmission: A systematic review and meta-analysis Content: BACKGROUND: Conflicting recommendations exist related to whether masks have a protective effect on the spread of respiratory viruses. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) statement was consulted to report this systematic review. Relevant articles were retrieved from PubMed, Web of Science, ScienceDirect, Cochrane Library, and Chinese National Knowledge Infrastructure (CNKI), VIP (Chinese) database. RESULTS: A total of 21 studies met our inclusion criteria. Meta-analyses suggest that mask use provided a significant protective effect (OR = 0.35 and 95% CI = 0.24–0.51). Use of masks by healthcare workers (HCWs) and non-healthcare workers (Non-HCWs) can reduce the risk of respiratory virus infection by 80% (OR = 0.20, 95% CI = 0.11–0.37) and 47% (OR = 0.53, 95% CI = 0.36–0.79). The protective effect of wearing masks in Asia (OR = 0.31) appeared to be higher than that of Western countries (OR = 0.45). Masks had a protective effect against influenza viruses (OR = 0.55), SARS (OR = 0.26), and SARS-CoV-2 (OR = 0.04). In the subgroups based on different study designs, protective effects of wearing mask were significant in cluster randomized trials and observational studies. CONCLUSIONS: This study adds additional evidence of the enhanced protective value of masks, we stress that the use masks serve as an adjunctive method regarding the COVID-19 outbreak.

Title: Teach, and teach and teach: does the average citizen use masks correctly during daily activities? Results from an observational study with more than 12,000 participants Content: COVID-19 is a new disease with no treatment and no vaccine so far. The pandemic is still growing in many areas. Among the core measures to prevent disease spread is the use of face masks. We observed 12,588 people in five Brazilian cities within the Baixada Santista metropolitan area. Even though this is densely populated region and heavily impacted by COVID-19 with a high risk population, only 45.1% of the observed population wore in face masks in a correct way, and another 15.5% simply did not use masks at all. The remainder used masks incorrectly, which is evidence of the worst scenario of people believing that they are protected when they are not. This is among the first studies, to the best of our knowledge, that measures real life compliance with face masks during this COVID-19 pandemic. It is our conclusion that it is paramount to first control the virus before allowing people back in the streets. We should not assume that people will wear masks properly. Equally important is to instruct and sensitize people on how to use face masks and why it is important.

Title: Comprehensive review of mask utility and challenges during the COVID-19 pandemic Content: Masks are widely discussed during the course of the ongoing COVID-19 pandemic Most hospitals have implemented universal masking for their healthcare workers, and the Center for Disease Control currently advises even the general public to wear cloth masks when outdoors The pertinent need for masks arises from plausible dissemination of the SARS-CoV-2 through close contacts, as well as the possibility of virus transmission from asymptomatic, pre-symptomatic, and mildly symptomatic individuals Given current global shortages in personal protective equipment, the efficacy of various types of masks: N95 respirators, surgical masks, and cloth masks are researched To accommodate limited supplies, techniques for extended use, reuse, and sterilization of masks are strategized However, masks alone may not greatly slow down the COVID-19 pandemic unless they are coupled with adequate social distancing, diligent hand hygiene, and other proven preventive measures

Title: Face Masks Considerably Reduce Covid-19 Cases in Germany Content: We use the synthetic control method to analyze the effect of face masks on the spread of Covid-19 in Germany. Our identification approach exploits regional variation in the point in time when face masks became compulsory. Depending on the region we analyse, we find that face masks reduced the cumulative number of registered Covid-19 cases between 2.3% and 13% over a period of 10 days after they became compulsory. Assessing the credibility of the various estimates, we conclude that face masks reduce the daily growth rate of reported infections by around 40%.

Title: The use of facemasks by the general population to prevent transmission of Covid 19 infection: A systematic review. Content: Background The pandemic of COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS- CoV-2), has become a serious worldwide public health emergency. This systematic review aims to summarize the available evidence regarding the role of face mask in community settings in slowing the spread of respiratory viruses such as SARS- CoV-2. Methods The preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were used for this review. A literature search using PUBMED, Google Scholar, and Cochrane database were performed using Medical subject heading (MeSH) words from the year 2000-2020. The articles focused on the use of masks and N95 respirators in healthcare workers were excluded. Results A total of 305 records were identified, out of which 14 articles were included in the review based upon quality and eligibility criteria. All the articles mentioned about the role of face masks in preventing the spread of respiratory viruses like influenza, SARS, and SARS-CoV-2, in the community or experimental setting. Studies also suggested that early initiation of face mask usage was more effective. Masks were also reported to be more effective in viruses that transmit easily from asymptomatic individuals, as is now known in SARS-CoV-2. Conclusion Theoretical, experimental, and clinical evidence suggested that usage of face masks in a general population offered significant benefit in preventing the spread of respiratory viruses especially in the pandemic situation, but its utility is limited by inconsistent adherence to mask usage.

Title: Masking the general population might attenuate COVID-19 outbreaks Content: The effect of masking the general population on a COVID-19 epidemic is estimated by computer simulation using two separate state-of-the-art web-based softwares, one of them calibrated for the SARS-CoV-2 virus. The questions addressed are these: 1. Can mask use by the general population limit the spread of SARS-CoV-2 in a country? 2. What types of masks exist, and how elaborate must a mask be to be effective against COVID-19? 3. Does the mask have to be applied early in an epidemic? 4. A brief general discussion of masks and some possible future research questions regarding masks and SARS-CoV-2. Results are as follows: (1) The results indicate that any type of mask, even simple home-made ones, may be effective. Masks use seems to have an effect in lowering new patients even the protective effect of each mask (here dubbed"one-mask protection") is low. Strict adherence to mask use does not appear to be critical. However, increasing the one-mask protection to>50% was found to be advantageous. Masks seemed able to reduce overflow of capacity, e.g. of intensive care. As the default parameters of the software included another intervention, it seems possible to combine mask and other interventions. (2) Masks do seem to reduce the number of new cases even if introduced at a late stage in an epidemic. However, early implementation helps reduce the cumulative and total number of cases. (3) The simulations suggest that it might be possible to eliminate a COVID-19 outbreak by widespread mask use during a limited period. The results from these simulations are encouraging, but do not necessarily represent the real-life situation, so it is suggested that clinical trials of masks are now carried out while continuously monitoring effects and side-effects.

Title: Comprehensive review of mask utility and challenges during the COVID-19 pandemic. Content: Masks are widely discussed during the course of the ongoing COVID-19 pandemic. Most hospitals have implemented universal masking for their healthcare workers, and the Center for Disease Control currently advises even the general public to wear cloth masks when outdoors. The pertinent need for masks arises from plausible dissemination of the SARS-CoV-2 through close contacts, as well as the possibility of virus transmission from asymptomatic, pre-symptomatic, and mildly symptomatic individuals. Given current global shortages in personal protective equipment, the efficacy of various types of masks: N95 respirators, surgical masks, and cloth masks are researched. To accommodate limited supplies, techniques for extended use, reuse, and sterilization of masks are strategized. However, masks alone may not greatly slow down the COVID-19 pandemic unless they are coupled with adequate social distancing, diligent hand hygiene, and other proven preventive measures.

Title: Widespread use of face masks in public may slow the spread of SARS CoV-2: an ecological study Content: Background The reasons for the large differences between countries in the sizes of their SARS CoV2 epidemics is unknown. Individual level studies have found that the use of face masks was protective for the acquisition and transmission of a range of respiratory viruses including SARS CoV1. We hypothesized that population level usage of face masks may be negatively associated SARS CoV2 spread. Methods At a country level, linear regression was used to assess the association between COVID19 diagnoses per inhabitant and the national promotion of face masks in public (coded as a binary variable), controlling for the age of the COVID19 epidemic and testing intensity. Results Eight of the 49 countries with available data advocated wearing face masks in public: China, Czechia, Hong Kong, Japan, Singapore, South Korea, Thailand and Malaysia. In multivariate analysis face mask use was negatively associated with number of COVID19 cases/inhabitant (coef. -326, 95% CI -601- -51, P=0.021). Testing intensity was positively associated with COVID-19 cases (coef. 0.07, 95% CI 0.05-0.08, P<0.001). Conclusion Whilst these results are susceptible to residual confounding, they do provide ecological level support to the individual level studies that found face mask usage to reduce the transmission and acquisition of respiratory viral infections.

Title: The scientific rationale for the use of simple masks or improvised facial coverings to trap exhaled aerosols and possibly reduce the breathborne spread of COVID-19 Content: The medical community agrees that breathborne infectious materials can be spread with exhaled aerosols and that asymptomatic people, i.e., those showing no symptoms, could be unknowingly infectious. With the current worldwide pandemic of the respiratory coronavirus disease 2019 (COVID-19), various health bodies and governments are recommending that the population wear some form of mask or improvised facial covers while out in public in an effort to reduce the spread of disease . The general concept is that more accessible masks or mask-like materials (scarves, bandanas, etc.) could serve to reduce the amount of infectious aerosol from infected people, and reduce the viral load in the environment. This editorial addresses the underlying scientific rationale that such inexpensive or improvised could indeed serve to reduce the emissions of infectious aerosol by the mechanism of surface adhesion and particle kinetics in addition to the filtration effect.

Title: Reply to Zhang et al.: Slowing the rate of spread of COVID-19 Content: Zhang et al. (2020) reported that mandating face coverings in public is necessary to decrease the rate of new COVID-19 infections. We present a counterexample that disproves this finding. We agree with Zhang et al. that masks can be an important element in reducing virus transmission and that widespread use may be essential for returning to full activity. However, their analysis neglects the potential importance of physical distancing for limiting COVID-19 transmission by misattributing its effect to mask requirements. A full suite of epidemiological tools is necessary in these challenging times.

Title: Estimating the Effect and Cost-Effectiveness of Facemasks in Reducing the Spread of the Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2) in Uganda Content: Evidence that face masks provide effective protection against respiratory infections in the community is scarce. However, face masks are widely used by health workers as part of droplet precautions when caring for patients with respiratory infections. It would therefore be reasonable to suggest that consistent widespread use of face masks in the community could prevent further spread of the Severe Acute Respiratory Syndrome-Coronavirus 2 (SARS-CoV-2). In this study we examine public face mask wearing in Uganda where a proportion wears masks to protect against acquiring, and the other to prevent from transmitting SARS-CoV-2. The objective of this study was to determine what percentage of the population would have to wear face masks to reduce susceptibility to and infectivity of COVID-19 in Uganda, keeping the basic reproduction number below unity and/or flattening the curve. We used an SEIAQRD model for the analysis. Results show that implementation of facemasks has a relatively large impact on the size of the coronavirus epidemic in Uganda. We find that the critical mask adherence is 5 per 100 when 80% wear face masks. A cost-effective analysis shows that utilizing funds to provide 1 public mask to the population has a per capita compounded cost of USD 1.34. If provision of face masks is done simultaneously with supportive care, the per capita compounded cost is USD 1.965, while for the case of only treatment and no provision of face masks costs each Ugandan USD 4.0579. We conclude that since it is hard to achieve a 100% adherence to face masks, government might consider provision of face masks in conjunction with provision of care.

Title: The effect of behavior of wearing masks on epidemic dynamics Content: Recently, COVID-19 has attracted a lot of attention of researchers from different fields. Wearing masks is a frequently adopted precautionary measure. In this paper, we investigate the effect of behavior of wearing masks on epidemic dynamics in the context of COVID-19. At each time, every susceptible individual chooses whether to wear a mask or not in the next time step, which depends on an evaluation of the potential costs and perceived risk of infection. When the cost of infection is high, the majority of the population choose to wear masks, where global awareness plays a significant role. However, if the mask source is limited, global awareness may give rise to a negative result. In this case, more mask source should be allocated to the individuals with high risk of infection.

Title: Community Use Of Face Masks And COVID-19: Evidence From A Natural Experiment Of State Mandates In The US Content: State policies mandating public or community use of face masks or covers in mitigating novel coronavirus disease (COVID-19) spread are hotly contested. This study provides evidence from a natural experiment on effects of state government mandates in the US for face mask use in public issued by 15 states plus DC between April 8 and May 15. The research design is an event study examining changes in the daily county-level COVID-19 growth rates between March 31, 2020 and May 22, 2020. Mandating face mask use in public is associated with a decline in the daily COVID-19 growth rate by 0.9, 1.1, 1.4, 1.7, and 2.0 percentage-points in 1-5, 6-10, 11-15, 16-20, and 21+ days after signing, respectively. Estimates suggest as many as 230,000-450,000 COVID-19 cases possibly averted By May 22, 2020 by these mandates. The findings suggest that requiring face mask use in public might help in mitigating COVID-19 spread. [Editor's Note: This Fast Track Ahead Of Print article is the accepted version of the peer-reviewed manuscript. The final edited version will appear in an upcoming issue of Health Affairs.].

Title: Community Use Of Face Masks And COVID-19: Evidence From A Natural Experiment Of State Mandates In The US. Content: State policies mandating public or community use of face masks or covers in mitigating novel coronavirus disease (COVID-19) spread are hotly contested. This study provides evidence from a natural experiment on effects of state government mandates in the US for face mask use in public issued by 15 states plus DC between April 8 and May 15. The research design is an event study examining changes in the daily county-level COVID-19 growth rates between March 31, 2020 and May 22, 2020. Mandating face mask use in public is associated with a decline in the daily COVID-19 growth rate by 0.9, 1.1, 1.4, 1.7, and 2.0 percentage-points in 1-5, 6-10, 11-15, 16-20, and 21+ days after signing, respectively. Estimates suggest as many as 230,000-450,000 COVID-19 cases possibly averted By May 22, 2020 by these mandates. The findings suggest that requiring face mask use in public might help in mitigating COVID-19 spread. [Editor's Note: This Fast Track Ahead Of Print article is the accepted version of the peer-reviewed manuscript. The final edited version will appear in an upcoming issue of Health Affairs.].

Title: COVID‐19: Face masks and human‐to‐human transmission Content: In December 2019, transmission of the novel coronavirus (SARS-CoV-2) that causes coronavirus disease 2019(COVID-19) occurred in Wuhan, China1 .And later the virus began to be transmitted from person to person2 .Face masks are a type of personal protective equipment used to prevent the spread of respiratory infections，it may be effective at helping prevent transmission of respiratory viruses and bacteria3 .Here, we share a case of face masks are be used to prevent the transmission of COVID-19 infection.

Title: A simple model to show the relative risk of viral aerosol infection and the benefit of wearing masks in different settings with implications for Covid-19 . Content: Background . Widespread use of masks in the general population is being used in many countries for Covid-19 . There has been reluctance on the part of the WHO and some governments to recommend this . Methodology . A basic model has been constructed to show the relative risk of aerosol from normal breathing in various situations together with the benefit from use of masks which is multiplicative . Results . Social distancing at 2 metres is validated but in confined areas is time limited and the use of masks in the absence of extremely good ventilation is important. Where social distancing is not possible at all times or an infectious person is in a confined area for a prolonged period there is a higher risk of infection requiring protection . Conclusions . The use of masks should be factored into models and used at an early stage as widespread use of more efficient masks could have a large impact on control and spread of infection . Public health planning requires stockpiling masks and encouraging everyone to have suitable masks in their household when supplies are normalised . The use of a cloth mask will be better than no protection at all .

Title: Medical mask or N95 respirator: When and how to use? Content: COVID-19 pandemic is now a global threat on human health reaching up to 2 million infected people all around the World. Since its first recognition in Wuhan, many topics were discussed intensively about COVID-19, both in the public and scientific community. Personal protective equipments and especially masks were among the hottest topics during this pandemic. Regardless of which mask is used, performing hand hygiene frequently with an alcohol-based hand rub or with soap and water if hands are dirty; is the most effective preventive measure for COVID-19. The type of mask used when caring for COVID-19 patients will vary according to the setting, type of personnel/person, and activity. Although the main transmission route for COVID-19 is droplets, during aerosol generating procedures airborne transmission may occur. Keeping the distancing and medical masks and eye protection during close contact efficiently protects against respiratory diseases transmitted via droplets. Airborne precautions include goggles and respiratory protection with the use of an N95 or an equivalent mask respirator to prevent airborne transmission.

Title: Medical mask or N95 respirator: When and how to use? Content: COVID-19 pandemic is now a global threat to human health reaching up to 2 million infected people all around the world. Since its first recognition in Wuhan, many topics were discussed intensively about COVID-19, both in the public and scientific community. Personal protective equipment, especially masks, has been among the hottest topics during this pandemic. Regardless of which mask is used, performing hand hygiene frequently with an alcohol-based hand rub or with soap and water if hands are dirty is the most effective preventive measure for COVID-19. The type of mask used when caring for COVID-19 patients will vary according to the setting, type of personnel/person, and activity. Although the main transmission route for COVID-19 is droplets, during aerosol generating procedures airborne transmission may occur. Keeping the distancing and medical masks and eye protection during close contact efficiently protects against respiratory diseases transmitted via droplets. Airborne precautions include goggles and respiratory protection with the use of an N95 or an equivalent mask respirator to prevent airborne transmission.

Title: Do Face Masks Create a False Sense of Security? A COVID-19 Dilemma Content: Face masks have become an emblem of the public response to COVID-19, with many governments mandating their use in public spaces. The logic is that face masks are low cost and might help prevent some transmission. However, from the start, the assumption that face masks are "low cost" was questioned. Early on, there were warnings of the opportunity cost of public use of medical masks given shortages of personal protective equipment for healthcare providers. This led to recommendations for cloth masks and other face coverings, with little evidence of their ability to prevent transmission. However, there may also be a high cost to these recommendations if people rely on face masks in place of other more effective ways to break transmission, such as staying home. We use SafeGraph smart device location data to show that the representative American in states that have face mask mandates spent 20-30 minutes less time at home, and increase visits to a number of commercial locations, following the mandate. Since the reproductive rate of SAR-COV2, the pathogen that causes COVID-19 is hovering right around one, such substitution behavior could be the difference between controlling the epidemic and a resurgence of cases.

Title: Universal Masking is Urgent in the COVID-19 Pandemic: SEIR and Agent Based Models, Empirical Validation, Policy Recommendations Content: We present two models for the COVID-19 pandemic predicting the impact of universal face mask wearing upon the spread of the SARS-CoV-2 virus--one employing a stochastic dynamic network based compartmental SEIR (susceptible-exposed-infectious-recovered) approach, and the other employing individual ABM (agent-based modelling) Monte Carlo simulation--indicating (1) significant impact under (near) universal masking when at least 80% of a population is wearing masks, versus minimal impact when only 50% or less of the population is wearing masks, and (2) significant impact when universal masking is adopted early, by Day 50 of a regional outbreak, versus minimal impact when universal masking is adopted late. These effects hold even at the lower filtering rates of homemade masks. To validate these theoretical models, we compare their predictions against a new empirical data set we have collected that includes whether regions have universal masking cultures or policies, their daily case growth rates, and their percentage reduction from peak daily case growth rates. Results show a near perfect correlation between early universal masking and successful suppression of daily case growth rates and/or reduction from peak daily case growth rates, as predicted by our theoretical simulations. Our theoretical and empirical results argue for urgent implementation of universal masking. As governments plan how to exit societal lockdowns, it is emerging as a key NPI; a"mouth-and-nose lockdown"is far more sustainable than a"full body lockdown", on economic, social, and mental health axes. An interactive visualization of the ABM simulation is at http://dek.ai/masks4all. We recommend immediate mask wearing recommendations, official guidelines for correct use, and awareness campaigns to shift masking mindsets away from pure self-protection, towards aspirational goals of responsibly protecting one's community.

Title: Cloth Masks May Prevent Transmission of COVID-19: An Evidence-Based, Risk-Based Approach Content: As the COVID-19 pandemic progressed across the world, governments, international agencies, policymakers, and public health officials began recommending widespread use of nonmedical cloth masks to reduce the transmission of SARS-CoV-2. The authors of this article suggest that there is convincing evidence to support this recommendation.

Title: How Efficient Can Non-Professional MasksSuppress COVID-19 Pandemic? Content: The coronavirus disease 2019 (COVID-19) pandemic is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which can be transmitted via respiratory secretions. Since there are currently no specific therapeutics or vaccines available against the SARS-CoV-2, the commen nonpharmaceutical interventions (NPIs) are still the main measures to curb the COVID-19 epidemic. Face mask wearing is one important measure to suppress the pandemic. In order to know how efficient is face mask wearing in reducing the pandemic even with low efficiency non-professional face masks, we exploit physical abstraction to model the non-professional face masks made from cotton woven fabrics and characterize them by a parameter virus penetration rate (VPR){gamma}. Monte Carlo simulations exhibit that the effective reproduction number R of COVID-19 or similar pandemics can be approximately reduced by factor {gamma}4 with respect to the basic reproduction number R0,if the face masks with 70% <{gamma}< 90% are universally applied for the entire network. Furthermore, thought experiments and practical exploitation examples in country-level and city-level are enumerated and discussed to support our discovery in this study and indicate that the outbreak of a COVID-19 like pandemic can be even suppressed by the low efficiency non-professional face masks.

Title: Can wearing face masks in public affect transmission route and viral load in COVID-19? Content: The mandatory face mask wearing was implemented in the Czech Republic and Slovakia shortly after the COVID-19 outbreak in Central Europe. So far, the number of COVID-19-associated deaths per 100,000 individuals is far lower in these countries as compared with other neighbouring or close countries. The use of face masks in public may not protect the general public from contracting the virus, however, presumptively decreases the viral load and contributes to a favourable clinical outcome in COVID-19 disease. A certain time is required for antigen-specific T cells and B cells to fully develop. Obligatory face mask wearing in public favours the virus transmission through oral mucosa and/or conjunctival epithelium, which enables the adaptive immune responses to evolve. In the case of inhalation of high loads of SARS-CoV-2, the time for the development of fully protective adaptive immune responses seems to be insufficient. Then, a less specific and more damaging innate immune response prevails.

Title: Rational use of face mask in a tertiary care hospital setting during COVID-19 pandemic: An observational study Content: Masks play a role in the protection of health-care workers (HCWs) from acquiring respiratory infections, including coronavirus disease 2019 (COVID-19) in health-care settings. This observational study was conducted among 382 HCWs in a tertiary care setting over a period of 1 month. Descriptive analysis was done to assess the rational and recommended use of masks/respirators during COVID-19 pandemic using a structured observation checklist as a survey tool. A total of 374 HCWs were included, 64.9% of whom were using face masks rationally as mentioned per risk area categorization with a predominance of triple-layered mask during all 4 weeks. Overall, 64.1% used masks correctly. Clear guidelines and strategies can help to increase the compliance of HCWs with rational use of face masks.

Title: Rational use of face mask in a tertiary care hospital setting during COVID-19 pandemic: An observational study. Content: Masks play a role in the protection of health-care workers (HCWs) from acquiring respiratory infections, including coronavirus disease 2019 (COVID-19) in health-care settings. This observational study was conducted among 382 HCWs in a tertiary care setting over a period of 1 month. Descriptive analysis was done to assess the rational and recommended use of masks/respirators during COVID-19 pandemic using a structured observation checklist as a survey tool. A total of 374 HCWs were included, 64.9% of whom were using face masks rationally as mentioned per risk area categorization with a predominance of triple-layered mask during all 4 weeks. Overall, 64.1% used masks correctly. Clear guidelines and strategies can help to increase the compliance of HCWs with rational use of face masks.

Title: Comparative efficacy of the front-line anti-HBV drugs in nucleos(t)ide analogue-naive chronic hepatitis B: A protocol for systematic review and network meta-analysis Content: BACKGROUND: During the COVID-19 period, there was a huge gap in the understanding of masks between east and west. At the same time, the mechanism of the mask and the effect after use, also appeared differences. The Objective of this Meta-analysis is to systematically evaluate the efficacy of masks for influenza in the community. METHODS: The Web of Science, PubMed, The Cochrane Library, EMBASE and Clinical Trials will be electronically searched to collect randomized controlled trials regarding the efficacy of masks for influenza in the community through Apr 2020. Two researchers independently screened and evaluated the obtained studies and extracted the outcome indexes. Revman 5.3 software will be used for the meta-analysis. RESULTS: The outbreak is continuing, and we need to be prepared for a long fight. If masks are effective, we need to promote their use as soon as possible. If masks are ineffective, strong evidence should be given. This is an urgent task and our team will finish it as soon as possible. CONCLUSION: Provide stronger evidence to solve the problem, should we wear masks or not right now.

Title: The efficacy of masks for influenza-like illness in the community: A protocol for systematic review and meta-analysis Content: BACKGROUND: During the COVID-19 period, there was a huge gap in the understanding of masks between east and west. At the same time, the mechanism of the mask and the effect after use, also appeared differences. The Objective of this Meta-analysis is to systematically evaluate the efficacy of masks for influenza in the community. METHODS: The Web of Science, PubMed, The Cochrane Library, EMBASE and Clinical Trials will be electronically searched to collect randomized controlled trials regarding the efficacy of masks for influenza in the community through Apr 2020. Two researchers independently screened and evaluated the obtained studies and extracted the outcome indexes. Revman 5.3 software will be used for the meta-analysis. RESULTS: The outbreak is continuing, and we need to be prepared for a long fight. If masks are effective, we need to promote their use as soon as possible. If masks are ineffective, strong evidence should be given. This is an urgent task and our team will finish it as soon as possible. CONCLUSION: Provide stronger evidence to solve the problem, should we wear masks or not right now.

Title: The Effect of Mask Use on the Spread of Influenza During a Pandemic Content: Face masks have traditionally been used in general infection control, but their efficacy at the population level in preventing transmission of influenza viruses has not been studied in detail. Data from published clinical studies indicate that the infectivity of influenza A virus is probably very high, so that transmission of infection may involve low doses of virus. At low doses, the relation between dose and the probability of infection is approximately linear, so that the reduction in infection risk is proportional to the reduction in exposure due to particle retention of the mask. A population transmission model was set up to explore the impact of population‐wide mask use, allowing estimation of the effects of mask efficacy and coverage (fraction of the population wearing masks) on the basic reproduction number and the infection attack rate. We conclude that population‐wide use of face masks could make an important contribution in delaying an influenza pandemic. Mask use also reduces the reproduction number, possibly even to levels sufficient for containing an influenza outbreak.

Title: Mask is the possible key for self‐isolation in COVID‐19 pandemic Content: Ma's research shows N95 masks, medical masks, even homemade masks could block at least 90% of the virus in aerosols(1). This study puts the debate on whether the public wear masks back on the table. Recently Science interviewed Dr. Gao, director‐general of Chinese Center for Disease Control and Prevention (CDC). This article is protected by copyright. All rights reserved.

Title: Visualizing the effectiveness of face masks in obstructing respiratory jets Content: The use of face masks in public settings has been widely recommended by public health officials during the current COVID-19 pandemic. The masks help mitigate the risk of cross-infection via respiratory droplets; however, there are no specific guidelines on mask materials and designs that are most effective in minimizing droplet dispersal. While there have been prior studies on the performance of medical-grade masks, there are insufficient data on cloth-based coverings, which are being used by a vast majority of the general public. We use qualitative visualizations of emulated coughs and sneezes to examine how material- and design-choices impact the extent to which droplet-laden respiratory jets are blocked. Loosely folded face masks and bandana-style coverings provide minimal stopping-capability for the smallest aerosolized respiratory droplets. Well-fitted homemade masks with multiple layers of quilting fabric, and off-the-shelf cone style masks, proved to be the most effective in reducing droplet dispersal. These masks were able to curtail the speed and range of the respiratory jets significantly, albeit with some leakage through the mask material and from small gaps along the edges. Importantly, uncovered emulated coughs were able to travel notably farther than the currently recommended 6-ft distancing guideline. We outline the procedure for setting up simple visualization experiments using easily available materials, which may help healthcare professionals, medical researchers, and manufacturers in assessing the effectiveness of face masks and other personal protective equipment qualitatively.

Title: Masks for Prevention of Respiratory Virus Infections, Including SARS-CoV-2, in Health Care and Community Settings: A Living Rapid Review Content: BACKGROUND: Recommendations on masks for preventing coronavirus disease 2019 (COVID-19) vary. PURPOSE: To examine the effectiveness of N95, surgical, and cloth masks in community and health care settings for preventing respiratory virus infections, and effects of reuse or extended use of N95 masks. DATA SOURCES: Multiple electronic databases, including the World Health Organization COVID-19 database and medRxiv preprint server (2003 through 14 April 2020; surveillance through 2 June 2020), and reference lists. STUDY SELECTION: Randomized trials of masks and risk for respiratory virus infection, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and observational studies of mask use and coronavirus infection risk were included. New evidence will be incorporated by using living review methods. DATA EXTRACTION: One reviewer abstracted data and assessed methodological limitations; a second reviewer provided verification. DATA SYNTHESIS: 39 studies (18 randomized controlled trials and 21 observational studies; 33 867 participants) were included. No study evaluated reuse or extended use of N95 masks. Evidence on SARS-CoV-2 was limited to 2 observational studies with serious limitations. Community mask use was possibly associated with decreased risk for SARS-CoV-1 infection in observational studies. In high- or moderate-risk health care settings, observational studies found that risk for infection with SARS-CoV-1 and Middle East respiratory syndrome coronavirus probably decreased with mask use versus nonuse and possibly decreased with N95 versus surgical mask use. Randomized trials in community settings found possibly no difference between N95 versus surgical masks and probably no difference between surgical versus no mask in risk for influenza or influenza-like illness, but compliance was low. In health care settings, N95 and surgical masks were probably associated with similar risks for influenza-like illness and laboratory-confirmed viral infection; clinical respiratory illness had inconsistency. Bothersome symptoms were common. LIMITATIONS: There were few SARS-CoV-2 studies, observational studies have methodological limitations, and the review was done by using streamlined methods. CONCLUSION: Evidence on mask effectiveness for respiratory infection prevention is stronger in health care than community settings. N95 respirators might reduce SARS-CoV-1 risk versus surgical masks in health care settings, but applicability to SARS-CoV-2 is uncertain. PRIMARY FUNDING SOURCE: Agency for Healthcare Research and Quality. Update Alerts: The authors have specified in the Methods section the interval and stop date for updates to this Living Review. As Annals receives updates, they will appear in the Comments section of the article on Annals.org. Reader inquiries about updates that are not available at approximately the specified intervals should be submitted as Comments to the article.

Title: Professional and Home-Made Face Masks Reduce Exposure to Respiratory Infections among the General Population Content: BACKGROUND: Governments are preparing for a potential influenza pandemic. Therefore they need data to assess the possible impact of interventions. Face-masks worn by the general population could be an accessible and affordable intervention, if effective when worn under routine circumstances. METHODOLOGY: We assessed transmission reduction potential provided by personal respirators, surgical masks and home-made masks when worn during a variety of activities by healthy volunteers and a simulated patient. PRINCIPAL FINDINGS: All types of masks reduced aerosol exposure, relatively stable over time, unaffected by duration of wear or type of activity, but with a high degree of individual variation. Personal respirators were more efficient than surgical masks, which were more efficient than home-made masks. Regardless of mask type, children were less well protected. Outward protection (mask wearing by a mechanical head) was less effective than inward protection (mask wearing by healthy volunteers). CONCLUSIONS/SIGNIFICANCE: Any type of general mask use is likely to decrease viral exposure and infection risk on a population level, in spite of imperfect fit and imperfect adherence, personal respirators providing most protection. Masks worn by patients may not offer as great a degree of protection against aerosol transmission.

Title: Mathematical Modeling of the Effectiveness of Facemasks in Reducing the Spread of Novel Influenza A (H1N1) Content: On June 11, 2009, the World Health Organization declared the outbreak of novel influenza A (H1N1) a pandemic. With limited supplies of antivirals and vaccines, countries and individuals are looking at other ways to reduce the spread of pandemic (H1N1) 2009, particularly options that are cost effective and relatively easy to implement. Recent experiences with the 2003 SARS and 2009 H1N1 epidemics have shown that people are willing to wear facemasks to protect themselves against infection; however, little research has been done to quantify the impact of using facemasks in reducing the spread of disease. We construct and analyze a mathematical model for a population in which some people wear facemasks during the pandemic and quantify impact of these masks on the spread of influenza. To estimate the parameter values used for the effectiveness of facemasks, we used available data from studies on N95 respirators and surgical facemasks. The results show that if N95 respirators are only 20% effective in reducing susceptibility and infectivity, only 10% of the population would have to wear them to reduce the number of influenza A (H1N1) cases by 20%. We can conclude from our model that, if worn properly, facemasks are an effective intervention strategy in reducing the spread of pandemic (H1N1) 2009.

Title: HUMAN CORONAVIRUS DATA FROM FOUR CLINICAL TRIALS OF MASKS AND RESPIRATORS Content: There are few published data on the protection of masks or respirators against coronavirus infections. This is an important research question to inform the response to the COVID-19 epidemic. The transmission modes of human coronaviruses are similar, thought to be by droplet, contact and sometimes airborne routes. There are several randomised clinical trials of masks and respirators, but most used clinical endpoints or tested only for influenza. In four trials which we conducted, we tested for human coronaviruses, but only composite viral endpoints were reported in the trials. We reviewed and analysed the coronavirus data from four of our trials. Laboratory-confirmed coronavirus infections were identified in our community household trial (1 case), health worker trials (8 cases) and trial of mask use by sick patients (19 cases). No coronavirus infections were transmitted in households to parents who wore P2 or surgical masks, but one child with coronavirus infection transmitted infection to a parent in the control arm. No transmissions to close contacts occurred when worn by sick patients with coronavirus infections. There was a higher risk of coronavirus infection in HCWs who wore a mask compared to a respirator, but the difference was not statistically significant. These are the only available data on coronavirus infections associated with mask or respirator use. More clinical trials are needed to assess the efficacy of respiratory protection against coronavirus infections.

Title: Human Coronavirus Data from Four Clinical Trials of Masks and Respirators Content: There are few published data on the protection of masks or respirators against coronavirus infections. This is an important research question to inform the response to the COVID-19 epidemic. The transmission modes of human coronaviruses are similar, thought to be by droplet, contact and sometimes airborne routes. There are several randomised clinical trials of masks and respirators, but most used clinical endpoints or tested only for influenza. In four trials which we conducted, we tested for human coronaviruses, but only composite viral endpoints were reported in the trials. We reviewed and analysed the coronavirus data from four of our trials. Laboratory-confirmed coronavirus infections were identified in our community household trial (1 case), health worker trials (8 cases) and trial of mask use by sick patients (19 cases). No coronavirus infections were transmitted in households to parents who wore P2 or surgical masks, but one child with coronavirus infection transmitted infection to a parent in the control arm. No transmissions to close contacts occurred when worn by sick patients with coronavirus infections. There was a higher risk of coronavirus infection in HCWs who wore a mask compared to a respirator, but the difference was not statistically significant. These are the only available data on coronavirus infections associated with mask or respirator use. More clinical trials are needed to assess the efficacy of respiratory protection against coronavirus infections.

Title: Examining the protection efficacy of face shields against cough aerosol droplets using water sensitive papers Content: Simple plastic face shields have many advantages compared to regular medical masks. They are easily cleaned for reuse and comfortable to wear. In light of the spreading COVID-19 pandemic, the potential of face shields as a substitution for medical masks, as a recommendation to the general population, was tested. Testing the efficacy of the protective equipment utilized a cough simulator that was carefully tuned to replicate human cough in terms of droplet size distribution and outlet velocity. The tested protective equipment was worn on a manikin head simulating human breathing. An Aerodynamic Particle Sizer (APS) was used to analyze the concentration and size distribution of small particles that reach the manikin head respiration pathways. Additionally, Water sensitive papers were taped over and under the tested protective equipment, and were subsequently photographed and analyzed. For droplets larger than 3m by diameter, the efficiency of shields to block cough droplets was found to be comparable to that of regular medical masks, with enhanced protection on face parts the mask does not cover. Additionally, for finer particles, of the order 0.3 to few microns, a shield was found to perform even better, blocking about 10 times more fine particles than the medical mask. This implies that for the general population that is not intendedly exposed to confirmed infected individuals, recommending the use of face shields as an alternative to medical masks should be considered.

Title: The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2 Content: BACKGROUND: Face mask usage by the healthy population in the community to reduce risk of transmission of respiratory viruses remains controversial. We assessed the effect of community-wide mask usage to control coronavirus disease 2019 (COVID-19) in Hong Kong Special Administrative Region (HKSAR). METHODS: Patients presenting with respiratory symptoms at outpatient clinics or hospital wards were screened for COVID-19 per protocol. Epidemiological analysis was performed for confirmed cases, especially persons acquiring COVID-19 during mask-off and mask-on settings. The incidence of COVID-19 per million population in HKSAR with community-wide masking was compared to that of non-mask-wearing countries which are comparable with HKSAR in terms of population density, healthcare system, BCG vaccination and social distancing measures but not community-wide masking. Compliance of face mask usage in the HKSAR community was monitored. FINDINGS: Within first 100 days (31 December 2019 to 8 April 2020), 961 COVID-19 patients were diagnosed in HKSAR. The COVID-19 incidence in HKSAR (129.0 per million population) was significantly lower (p<0.001) than that of Spain (2983.2), Italy (2250.8), Germany (1241.5), France (1151.6), U.S. (1102.8), U.K. (831.5), Singapore (259.8), and South Korea (200.5). The compliance of face mask usage by HKSAR general public was 96.6% (range: 95.7% to 97.2%). We observed 11 COVID-19 clusters in recreational 'mask-off' settings compared to only 3 in workplace 'mask-on' settings (pâ¯=â¯0.036 by Chi square test of goodness-of-fit). CONCLUSION: Community-wide mask wearing may contribute to the control of COVID-19 by reducing the amount of emission of infected saliva and respiratory droplets from individuals with subclinical or mild COVID-19.

Title: 'Masking the evidence': perspectives of the COVID-19 pandemic Content: The COVID-19 pandemic presents a severe and acute public health emergency around the world. The event of the pandemic has seen an upsurge in the general public wearing of disposable surgical masks (DSM) and other types of face masks. The World Health Organisation of mask wearing has been widely debated in the press a(WHO) have changed their advice, to now recommend the routine wearing of fabric masks by the general public as a means of preventing the spread of COVID-19 (WHO 2020a).

Title: Facemasks and similar barriers to prevent respiratory illness such as COVID-19: A rapid systematic review Content: The current pandemic of COVID-19 has lead to conflicting opinions on whether wearing facemasks outside of health care facilities protects against the infection. To better understand the value of wearing facemasks we undertook a rapid systematic review of existing scientific evidence about development of respiratory illness, linked to use of facemasks in community settings. METHODS: We included all study designs. There were 31 eligible studies (including 12 RCTs). Narrative synthesis and random-effects meta-analysis of attack rates for primary and secondary prevention in 28 studies were performed. Results were reported by design, setting and type of face barrier in primary prevention, and by who wore the facemask (index patient or well contacts) in secondary prevention trials. The preferred outcome was influenza-like illness (ILI) but similar outcomes were pooled with ILI when ILI was unavailable. GRADE quality assessment was based on RCTs with support from observational studies. RESULTS: Where specific information was available, most studies reported about use of medical grade (surgical paper masks). In 3 RCTs, wearing a facemask may very slightly reduce the odds of developing ILI/respiratory symptoms, by around 6% (OR 0.94, 95% CI 0.75 to 1.19, I2 29%, low certainty evidence). Greater effectiveness was suggested by observational studies. When both house-mates and an infected household member wore facemasks the odds of further household members becoming ill may be modestly reduced by around 19% (OR 0.81, 95%CI 0.48 to 1.37, I 2 45%, 5 RCTs, low certainty evidence). The protective effect was very small if only the well person(OR 0.93, 95% CI 0.68 to 1.28, I2 11%, 2 RCTs, low uncertainty evidence) or the infected person wore the facemask (very low certainty evidence). DISCUSSION: Based on the RCTs we would conclude that wearing facemasks can be very slightly protective against primary infection from casual community contact, and modestly protective against household infections when both infected and uninfected members wear facemasks. However, the RCTs often suffered from poor compliance and controls using facemasks. Across observational studies the evidence in favour of wearing facemasks was stronger. We expect RCTs to under-estimate the protective effect and observational studies to exaggerate it. The evidence is not sufficiently strong to support widespread use of facemasks as a protective measure against COVID-19. However, there is enough evidence to support the use of facemasks for short periods of time by particularly vulnerable individuals when in transient higher risk situations. Further high quality trials are needed to assess when wearing a facemask in the community is most likely to be protective.

Title: Understanding the Impact of Face Mask Usage Through Epidemic Simulation of Large Social Networks Content: Evidence from the 2003 SARS epidemic and 2009 H1N1 pandemic shows that face masks can be an effective non-pharmaceutical intervention in minimizing the spread of airborne viruses. Recent studies have shown that using face masks is correlated to an individual’s age and gender, where females and older adults are more likely to wear a mask than males or youths. There are only a few studies quantifying the impact of using face masks to slow the spread of an epidemic at the population level, and even fewer studies that model their impact in a population where the use of face masks depends upon the age and gender of the population. We use a state-of-the-art agent-based simulation to model the use of face masks and quantify their impact on three levels of an influenza epidemic and compare different mitigation scenarios. These scenarios involve changing the demographics of mask usage, the adoption of mask usage in relation to a perceived threat level, and the combination of masks with other non-pharmaceutical interventions such as hand washing and social distancing. Our results shows that face masks alone have limited impact on the spread of influenza. However, when face masks are combined with other interventions such as hand sanitizer, they can be more effective. We also observe that monitoring social internet systems can be a useful technique to measure compliance. We conclude that educating the public on the effectiveness of masks to increase compliance can reduce morbidity and mortality.

Title: The use of facemasks may not lead to an increase in hand-face contact Content: Advocacy of the use of facemasks by the public as a measure against the spread of COVID-19 is controversial, with some healthcare professionals arguing that the use of a face mask may increase the rate at which people touch their faces, due to readjusting the mask. We assessed the facial touching behaviour of bus passengers in China before and after the outbreak of COVID-19 and found that wearing a face mask does not increase the number of hand-face contacts and is likely, therefore, to have a positive beneficial effect on suppressing the spread of COVID-19 within populations when used in conjunction with social distancing measures.

Title: Identifying airborne transmission as the dominant route for the spread of COVID-19 Content: Various mitigation measures have been implemented to fight the coronavirus disease 2019 (COVID-19) pandemic, including widely adopted social distancing and mandated face covering. However, assessing the effectiveness of those intervention practices hinges on the understanding of virus transmission, which remains uncertain. Here we show that airborne transmission is highly virulent and represents the dominant route to spread the disease. By analyzing the trend and mitigation measures in Wuhan, China, Italy, and New York City, from January 23 to May 9, 2020, we illustrate that the impacts of mitigation measures are discernable from the trends of the pandemic. Our analysis reveals that the difference with and without mandated face covering represents the determinant in shaping the pandemic trends in the three epicenters. This protective measure alone significantly reduced the number of infections, that is, by over 78,000 in Italy from April 6 to May 9 and over 66,000 in New York City from April 17 to May 9. Other mitigation measures, such as social distancing implemented in the United States, are insufficient by themselves in protecting the public. We conclude that wearing of face masks in public corresponds to the most effective means to prevent interhuman transmission, and this inexpensive practice, in conjunction with simultaneous social distancing, quarantine, and contact tracing, represents the most likely fighting opportunity to stop the COVID-19 pandemic. Our work also highlights the fact that sound science is essential in decision-making for the current and future public health pandemics.

Title: Is wearing a face mask safe for people with epilepsy? Content: Since December 2019, the world has been experiencing a catastrophic pandemic of coronavirus disease (COVID-19) caused by SARS-CoV2. This virus primarily targets the human respiratory system. Available information suggests that people with epilepsy (PWE) are not at higher risk of being infected by the virus, nor of more severe COVID-19 manifestations, as a result of the epilepsy alone. However, COVID-19 is a serious disease that currently has no effective treatment or vaccine. A face mask is probably effective in preventing the spread of a respiratory pathogen, at least to some extent. So, should we recommend wearing a face mask to all during a pandemic of respiratory infectious disease (e.g., COVID-19) without any precautions or exemptions? While concrete evidence is lacking, if we consider that wearing a face mask may simulate hyperventilation, at least to some extent, we would probably avoid recommending this practice indiscriminately to all PWE. On the other hand, in the absence of any proven treatment or vaccine to combat COVID-19, prevention is the best available strategy and it is probably not reasonable to suggest avoid wearing face masks in PWE under any circumstances. Logically, PWE do not need to wear a face mask most of the time, as long as there is no close contact with others, especially during intense physical activities such as exercise. To the contrary, it is probably more advantageous to wear a face mask in crowded locations, with intermittent breaks in safe locations, away from others.

Title: Study of Air Curtain in Context of Individual Protection from Exposure to Coronavirus (SARS-CoV-2) Contained in Cough-Generated Fluid Particles Content: The ongoing respiratory COVID-19 pandemic has heavily impacted the social and private lives of the majority of the global population. This infection is primarily transmitted via virus-laden fluid particles (i.e., droplets and aerosols) that are formed in the respiratory tract of infected individuals and expelled from the mouth in the course of breathing, talking, coughing, and sneezing. To mitigate the risk of virus transmission, in many places of the world, the public has been asked or even obliged to use face covers. It is plausible that in the years ahead we will see the use of face masks, face shields and respirators become a normal practice in our life. However, wearing face covers is uncomfortable in some situations, like, for example, in summer heat, while staying on beaches or at hotel swimming pools, doing exercises in gyms, etc. Also, most types of face cover become contaminated with time and need to be periodically replaced or disinfected. These nuisances are caused by the fact that face covers are based on material barriers, which prevent inward and outward propagation of aerosol and droplets containing the pathogen. Applying well established gas-particle flow formalism, we study a non-material based protection barrier created by a flow of well directed down stream of air across the front of the open face. The~protection is driven by dragging virus-laden particles inside the width of the air flow and hence, as a consequence, displacing them away from their primary trajectories. The study, shows that such, potentially portable, air curtains can effectively provide both inward and outward protection and serve as an effective personal protective equipment (PPE) mitigating human to human transmission of virus infection like COVID-19.

Title: Low-cost measurement of facemask efficacy for filtering expelled droplets during speech Content: Mandates for mask use in public during the recent COVID-19 pandemic, worsened by global shortage of commercial supplies, have led to widespread use of homemade masks and mask alternatives. It is assumed that wearing such masks reduces the likelihood for an infected person to spread the disease, but many of these mask designs have not been tested in practice. We have applied a simple optical measurement method to evaluate the efficacy of masks to reduce the transmission of respiratory droplets during regular speech. We compare a variety of commonly available mask types and observe that some mask types approach the performance of standard surgical masks, while some mask alternatives, such as neck fleece or bandanas, offer very little protection. Our measurement setup is inexpensive and can be built and operated by non-experts, allowing for rapid evaluation of mask performance during speech, sneezing, or coughing.

Title: Risk of SARS-CoV-2 transmission by aerosols, the rational use of masks, and protection of healthcare workers from COVID-19 Content: OBJECTIVES: To determine the risk of SARS-CoV-2 transmission by aerosols, to provide evidence on the rational use of masks, and to discuss additional measures important for the protection of healthcare workers from COVID-19. METHODS: Literature review and expert opinion. SHORT CONCLUSION: SARS-CoV-2, the pathogen causing COVID-19, is considered to be transmitted via droplets rather than aerosols, but droplets with strong directional airflow support may spread further than 2 m. High rates of COVID-19 infections in healthcare-workers (HCWs) have been reported from several countries. Respirators such as filtering face piece (FFP) 2 masks were designed to protect HCWs, while surgical masks were originally intended to protect patients (e.g., during surgery). Nevertheless, high quality standard surgical masks (type II/IIR according to European Norm EN 14683) appear to be as effective as FFP2 masks in preventing droplet-associated viral infections of HCWs as reported from influenza or SARS. So far, no head-to-head trials with these masks have been published for COVID-19. Neither mask type completely prevents transmission, which may be due to inappropriate handling and alternative transmission pathways. Therefore, compliance with a bundle of infection control measures including thorough hand hygiene is key. During high-risk procedures, both droplets and aerosols may be produced, reason why respirators are indicated for these interventions.

Title: Universal Masking during Covid-19 Pandemic - Current Evidence and Controversies Content: The emergence of coronavirus disease 19 pandemic and novel research on the high transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has raised controversies over the use of face masks to prevent community transmission. Specific regulations need to be fulfilled to use a face mask as part of the personal protective equipment and high quality of evidence supporting its use to prevent respiratory viral infections, including SARS-CoV-2, is lacking. However, its widespread use is becoming a standard practice in some countries and discrepancies between health authorities on their policy have led to controversy. The aim of this review is to provide an outlook on recent research in this matter and areas of opportunity.

Title: UNIVERSAL MASKING DURING COVID-19 PANDEMIC - CURRENT EVIDENCE AND CONTROVERSIES. Content: The emergence of coronavirus disease 19 pandemic and novel research on the high transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has raised controversies over the use of face masks to prevent community transmission. Specific regulations need to be fulfilled to use a face mask as part of the personal protective equipment and high quality of evidence supporting its use to prevent respiratory viral infections, including SARS-CoV-2, is lacking. However, its widespread use is becoming a standard practice in some countries and discrepancies between health authorities on their policy have led to controversy. The aim of this review is to provide an outlook on recent research in this matter and areas of opportunity.

Title: Physical interventions to interrupt or reduce the spread of respiratory viruses. Part 1 - Face masks, eye protection and person distancing: systematic review and meta-analysis Content: Abstract OBJECTIVE: To examine the effectiveness of eye protection, face masks, or person distancing on interrupting or reducing the spread of respiratory viruses. DESIGN: Update of a Cochrane review that included a meta-analysis of observational studies during the SARS outbreak of 2003. DATA SOURCES: Eligible trials from the previous review; search of Cochrane Central Register of Controlled Trials, PubMed, Embase and CINAHL from October 2010 up to 1 April 2020; and forward and backward citation analysis. DATA SELECTION: Randomised and cluster-randomised trials of people of any age, testing the use of eye protection, face masks, or person distancing against standard practice, or a similar physical barrier. Outcomes included any acute respiratory illness and its related consequences. DATA EXTRACTION AND ANALYSIS: Six authors independently assessed risk of bias using the Cochrane tool and extracted data. We used a generalised inverse variance method for pooling using a random-effects model and reported results with risk ratios and 95% Confidence Intervals (CI). RESULTS: We included 15 randomised trials investigating the effect of masks (14 trials) in healthcare workers and the general population and of quarantine (1 trial). We found no trials testing eye protection. Compared to no masks there was no reduction of influenza-like illness (ILI) cases (Risk Ratio 0.93, 95%CI 0.83 to 1.05) or influenza (Risk Ratio 0.84, 95%CI 0.61-1.17) for masks in the general population, nor in healthcare workers (Risk Ratio 0.37, 95%CI 0.05 to 2.50). There was no difference between surgical masks and N95 respirators: for ILI (Risk Ratio 0.83, 95%CI 0.63 to 1.08), for influenza (Risk Ratio 1.02, 95%CI 0.73 to 1.43). Harms were poorly reported and limited to discomfort with lower compliance. The only trial testing quarantining workers with household ILI contacts found a reduction in ILI cases, but increased risk of quarantined workers contracting influenza. All trials were conducted during seasonal ILI activity. CONCLUSIONS: Most included trials had poor design, reporting and sparse events. There was insufficient evidence to provide a recommendation on the use of facial barriers without other measures. We found insufficient evidence for a difference between surgical masks and N95 respirators and limited evidence to support effectiveness of quarantine. Based on observational evidence from the previous SARS epidemic included in the previous version of our Cochrane review we recommend the use of masks combined with other measures.

Title: The role of community-wide wearing of face mask for control of coronavirus disease 2019 (COVID-19) epidemic due to SARS-CoV-2 Content: Abstract Background Face mask usage by the healthy population in the community to reduce risk of transmission of respiratory viruses remains controversial. We assessed the effect of community-wide mask usage to control coronavirus disease 2019 (COVID-19) in Hong Kong Special Administrative Region (HKSAR). Methods Patients presenting with respiratory symptoms at outpatient clinics or hospital wards were screened for COVID-19 per protocol. Epidemiological analysis was performed for confirmed cases, especially persons acquiring COVID-19 during mask-off and mask-on settings. The incidence of COVID-19 per-million-population in HKSAR with community-wide masking was compared to that of non-mask-wearing countries which are comparable with HKSAR in terms of population density, healthcare system, BCG vaccination and social distancing measures but not community-wide masking. Compliance of face mask usage in the HKSAR community was monitored. Findings Within first 100 days (31 December 2019 to 8 April 2020), 961 COVID-19 patients were diagnosed in HKSAR. The COVID-19 incidence in HKSAR (129.0 per-million-population) was significantly lower (p<0.001) than that of Spain (2983.2), Italy (2250.8), Germany (1241.5), France (1151.6), U.S. (1102.8), U.K. (831.5), Singapore (259.8), and South Korea (200.5). The compliance of face mask usage by HKSAR general public was 96.6% (range: 95.7% to 97.2%). We observed 11 COVID-19 clusters in recreational ‘mask-off’ settings compared to only 3 in workplace ‘mask-on’ settings (p = 0.036 by Chi square test of goodness-of-fit). Conclusion Community-wide mask wearing may contribute to the control of COVID-19 by reducing virus shedding in saliva and respiratory droplets from individuals with subclinical or mild COVID-19.

Title: The N-95 mask: invaluable ally in the battle against the COVID-19 pandemic Content: The present COVID-19 pandemic, caused by the airborne SARS-CoV-2 virus, has highlighted the vital importance of appropriate personal protective equipment for all exposed health care workers The single most important part of this armor is the N-95 mask With the awareness that the virus is spread by both droplets and through the aerosolized route, the N-95 provides protection that a surgical mask cannot match This timely review looks at the special advantages that an N-95 offers over a surgical mask with specific reference to the COVID-19 epidemic It also emphasizes the crucial importance of ensuring quality masks with a proper fit Finally, with acute scarcities of N-95 masks being reported from hospitals globally, it reviews recent literature which attempts to prolong the life of these masks with extended use, reuse and decontamination of used masks

Title: Does Collective Interest or Self-Interest Motivate Mask Usage as a Preventive Measure Against COVID-19? Content: The revised guidance on masks from public health officials has been one of the most significant COVID-19 policy reversals to date. Statements made at the outset of the pandemic, including those from the World Health Organization (WHO), the United States Surgeon General, and the Chief Public Health Officer of Canada, all actively discouraged asymptomatic members of the general public from wearing masks. However, on April 3, 2020, the United States Center for Disease Control and Prevention (CDC) issued new recommendations that called for nonmedical masks, such as cloth face coverings, to be worn in public settings where other social distancing measures are difficult to maintain (Adams, 2020). Canadian public health officials quickly followed with their own guidance for wearing nonmedical masks or face coverings when out in public; however, they have stressed that doing so is optional for asymptomatic persons and should be seen as a complement to existing precautionary measures such as physical distancing and hand hygiene, particularly in cases where physical distancing may not be feasible (Public Health Agency of Canada, 2020). Emphasis was placed on nonmedical masks serving not to protect the wearer, but rather others who come within close proximity of the wearer. Echoing her public statements on the matter, Canada's chief public health officer Tweeted that “[w]earing a NON-MEDICAL mask in public settings has not been proven to add any protection TO the person wearing it, but it can be an additional way to prevent spread FROM an infected person to others” (Tam, 2020).

Title: ‘Masking the evidence’: perspectives of the COVID‐19 pandemic Content: The COVID‐19 pandemic presents a severe and acute public health emergency around the world. The event of the pandemic has seen an upsurge in the general public wearing of disposable surgical masks (DSM) and other types of face masks. The World Health Organisation of mask wearing has been widely debated in the press a(WHO) have changed their advice, to now recommend the routine wearing of fabric masks by the general public as a means of preventing the spread of COVID‐19 (WHO 2020a).

Title: COVID-19: emerging protective measures Content: The COVID-19 (Coronavirus disease 2019) spreads primarily through droplets of saliva or discharge from the nose. COVID-19 is predominantly considered as an unavoidable pandemic, and scientists are very curious about how to provide the best protection to the public before a vaccine can be made available. There is an urge to manufacture a greater number of masks to prevent any aerosol with microbes. Hence, we aim to develop an efficient viral inactivation system by exploiting active compounds from naturally occurring medicinal plants and infusing them into nanofiber-based respiratory masks. Our strategy is to develop fibrous filtration with three-layered masks using the compounds from medicinal plants for viral deactivation. These masks will be beneficial not just to healthcare workers but common citizens as well. In the absence of vaccination, productive masks can be worn to prevent transmission of airborne pathogenic aerosols and control diseases.

Title: COVID-19: emerging protective measures. Content: The COVID-19 (Coronavirus disease 2019) spreads primarily through droplets of saliva or discharge from the nose. COVID-19 is predominantly considered as an unavoidable pandemic, and scientists are very curious about how to provide the best protection to the public before a vaccine can be made available. There is an urge to manufacture a greater number of masks to prevent any aerosol with microbes. Hence, we aim to develop an efficient viral inactivation system by exploiting active compounds from naturally occurring medicinal plants and infusing them into nanofiber-based respiratory masks. Our strategy is to develop fibrous filtration with three-layered masks using the compounds from medicinal plants for viral deactivation. These masks will be beneficial not just to healthcare workers but common citizens as well. In the absence of vaccination, productive masks can be worn to prevent transmission of airborne pathogenic aerosols and control diseases.

Title: Performance of fabrics for home-made masks against spread of respiratory infection through droplets: a quantitative mechanistic study Content: Respiratory infections may spread through droplets, airborne particles, and aerosols from infected individuals through coughing, sneezing, and speaking. In the case of Coronavirus Disease 2019 (COVID-19), droplet spread can occur from symptomatic as well as pre-symptomatic and asymptomatic persons. The U.S. Centers for Disease Control and Prevention (CDC) has therefore recently recommended home-made cloth face coverings for use by the general public in areas of significant community-based transmission. Because medical masks and N95 respirators are in short supply, these are to be reserved for healthcare workers. There is, however, little information on the effectiveness of home-made face coverings in reducing droplet dissemination. Here, we ascertained the performance of ten different fabrics, ranging from cotton to silk, in blocking high velocity droplets, using a 3-layered commercial medical mask as a benchmark material. We also assessed their breathability and ability to soak water. We reason that the materials should be as breathable as possible, without compromising blocking efficiency, to reduce air flow through the sides of the mask since such flow would defeat the purpose of the mask. We found that most home fabrics substantially block droplets, even as a single layer. With two layers, blocking performance can reach that of surgical mask without significantly compromising breathability. Furthermore, we observed that home fabrics are hydrophilic to varying degrees, and hence soak water. In contrast, medical masks are hydrophobic, and tend to repel water. Incoming droplets are thus soaked and 'held back' by home fabrics, which might offer an as of yet untapped and understudied advantage of home-made cloth masks. Overall, our study suggests that most double-layered cloth face coverings may help reduce droplet transmission of respiratory infections.

Title: Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis Content: BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and is spread person-to-person through close contact. We aimed to investigate the effects of physical distance, face masks, and eye protection on virus transmission in health-care and non-health-care (eg, community) settings. METHODS: We did a systematic review and meta-analysis to investigate the optimum distance for avoiding person-to-person virus transmission and to assess the use of face masks and eye protection to prevent transmission of viruses. We obtained data for SARS-CoV-2 and the betacoronaviruses that cause severe acute respiratory syndrome, and Middle East respiratory syndrome from 21 standard WHO-specific and COVID-19-specific sources. We searched these data sources from database inception to May 3, 2020, with no restriction by language, for comparative studies and for contextual factors of acceptability, feasibility, resource use, and equity. We screened records, extracted data, and assessed risk of bias in duplicate. We did frequentist and Bayesian meta-analyses and random-effects meta-regressions. We rated the certainty of evidence according to Cochrane methods and the GRADE approach. This study is registered with PROSPERO, CRD42020177047. FINDINGS: Our search identified 172 observational studies across 16 countries and six continents, with no randomised controlled trials and 44 relevant comparative studies in health-care and non-health-care settings (n=25 697 patients). Transmission of viruses was lower with physical distancing of 1 m or more, compared with a distance of less than 1 m (n=10 736, pooled adjusted odds ratio [aOR] 0·18, 95% CI 0·09 to 0·38; risk difference [RD] −10·2%, 95% CI −11·5 to −7·5; moderate certainty); protection was increased as distance was lengthened (change in relative risk [RR] 2·02 per m; p(interaction)=0·041; moderate certainty). Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD −14·3%, −15·9 to −10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (eg, reusable 12–16-layer cotton masks; p(interaction)=0·090; posterior probability >95%, low certainty). Eye protection also was associated with less infection (n=3713; aOR 0·22, 95% CI 0·12 to 0·39, RD −10·6%, 95% CI −12·5 to −7·7; low certainty). Unadjusted studies and subgroup and sensitivity analyses showed similar findings. INTERPRETATION: The findings of this systematic review and meta-analysis support physical distancing of 1 m or more and provide quantitative estimates for models and contact tracing to inform policy. Optimum use of face masks, respirators, and eye protection in public and health-care settings should be informed by these findings and contextual factors. Robust randomised trials are needed to better inform the evidence for these interventions, but this systematic appraisal of currently best available evidence might inform interim guidance. FUNDING: World Health Organization.

Title: A rapid systematic review of the efficacy of face masks and respirators against coronaviruses and other respiratory transmissible viruses for the community, healthcare workers and sick patients Content: BACKGROUND: The pandemic of COVID-19 is growing, and a shortage of masks and respirators has been reported globally. Policies of health organizations for healthcare workers are inconsistent, with a change in policy in the US for universal face mask use. The aim of this study was to review the evidence around the efficacy of masks and respirators for healthcare workers, sick patients and the general public. METHODS: A systematic review of randomized controlled clinical trials on use of respiratory protection by healthcare workers, sick patients and community members was conducted. Articles were searched on Medline and Embase using key search terms. RESULTS: A total of 19 randomised controlled trials were included in this study - 8 in community settings, 6 in healthcare settings and 5 as source control. Most of these randomised controlled trials used different interventions and outcome measures. In the community, masks appeared to be effective with and without hand hygiene, and both together are more protective. Randomised controlled trials in health care workers showed that respirators, if worn continually during a shift, were effective but not if worn intermittently. Medical masks were not effective, and cloth masks even less effective. When used by sick patients randomised controlled trials suggested protection of well contacts. CONCLUSION: The study suggests that community mask use by well people could be beneficial, particularly for COVID-19, where transmission may be pre-symptomatic. The studies of masks as source control also suggest a benefit, and may be important during the COVID-19 pandemic in universal community face mask use as well as in health care settings. Trials in healthcare workers support the use of respirators continuously during a shift. This may prevent health worker infections and deaths from COVID-19, as aerosolisation in the hospital setting has been documented.

Title: Physical distancing, face masks, and eye protection to prevent person-to-person transmission of SARS-CoV-2 and COVID-19: a systematic review and meta-analysis Content: BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19 and is spread person-to-person through close contact. We aimed to investigate the effects of physical distance, face masks, and eye protection on virus transmission in health-care and non-health-care (eg, community) settings. METHODS: We did a systematic review and meta-analysis to investigate the optimum distance for avoiding person-to-person virus transmission and to assess the use of face masks and eye protection to prevent transmission of viruses. We obtained data for SARS-CoV-2 and the betacoronaviruses that cause severe acute respiratory syndrome, and Middle East respiratory syndrome from 21 standard WHO-specific and COVID-19-specific sources. We searched these data sources from database inception to May 3, 2020, with no restriction by language, for comparative studies and for contextual factors of acceptability, feasibility, resource use, and equity. We screened records, extracted data, and assessed risk of bias in duplicate. We did frequentist and Bayesian meta-analyses and random-effects meta-regressions. We rated the certainty of evidence according to Cochrane methods and the GRADE approach. This study is registered with PROSPERO, CRD42020177047. FINDINGS: Our search identified 172 observational studies across 16 countries and six continents, with no randomised controlled trials and 44 relevant comparative studies in health-care and non-health-care settings (n=25â697 patients). Transmission of viruses was lower with physical distancing of 1 m or more, compared with a distance of less than 1 m (n=10â736, pooled adjusted odds ratio [aOR] 0·18, 95% CI 0·09 to 0·38; risk difference [RD] -10·2%, 95% CI -11·5 to -7·5; moderate certainty); protection was increased as distance was lengthened (change in relative risk [RR] 2·02 per m; pinteraction=0·041; moderate certainty). Face mask use could result in a large reduction in risk of infection (n=2647; aOR 0·15, 95% CI 0·07 to 0·34, RD -14·3%, -15·9 to -10·7; low certainty), with stronger associations with N95 or similar respirators compared with disposable surgical masks or similar (eg, reusable 12-16-layer cotton masks; pinteraction=0·090; posterior probability >95%, low certainty). Eye protection also was associated with less infection (n=3713; aOR 0·22, 95% CI 0·12 to 0·39, RD -10·6%, 95% CI -12·5 to -7·7; low certainty). Unadjusted studies and subgroup and sensitivity analyses showed similar findings. INTERPRETATION: The findings of this systematic review and meta-analysis support physical distancing of 1 m or more and provide quantitative estimates for models and contact tracing to inform policy. Optimum use of face masks, respirators, and eye protection in public and health-care settings should be informed by these findings and contextual factors. Robust randomised trials are needed to better inform the evidence for these interventions, but this systematic appraisal of currently best available evidence might inform interim guidance. FUNDING: World Health Organization.

Title: Quantifying Respiratory Airborne Particle Dispersion Control Through Improvised Reusable Masks Content: Objective: To determine the effectiveness of non-medical grade washable masks or face coverings in controlling airborne dispersion from exhalation (both droplet and aerosol), and to aid in establishing public health strategies on the wearing of masks to reduce COVID-19 transmission. Design: This comparative effectiveness study using an exhalation simulator to conduct 94 experiment runs with combinations of 8 different fabrics, 5 mask designs, and airflows for both talking and coughing. Setting: Non-airtight fume hood and multiple laser scattering particle sensors. Participants: No human participants. Exposure: 10% NaCl nebulized solution delivered by an exhalation simulator through various masks and fabrics with exhalation airflows representative of "coughing" and "talking or singing." Main Outcomes and Measures: The primary outcome was reduction in aerosol dispersion velocity, quantity of particles, and change in dispersion direction. Measurements used in this study included peak expiratory flow (PEF), aerosol velocity, concentration area under curve (AUC), and two novel metrics of expiratory flow dispersion factor (EDF) and filtration efficiency indicator (FEI). Results: Three-way multivariate analysis of variance establishes that factors of fabric, mask design, and exhalation breath level have a statistically significant effect on changing direction, reducing velocity or concentration (Fabric: P = < .001, Wilks' {Lambda} = .000; Mask design: P = < .001, Wilks' {Lambda} = .000; Breath level: P = < .001, Wilks' {Lambda} = .004). There were also statistically significant interaction effects between combinations of all primary factors. Conclusions and Relevance: The application of facial coverings or masks can significantly reduce the airborne dispersion of aerosolized particles from exhalation. The results show that wearing of non-medical grade washable masks or face coverings can help increase the effectiveness of non-pharmaceutical interventions (NPI) especially where infectious contaminants may exist in shared air spaces. However, the effectiveness varies greatly between the specific fabrics and mask designs used.

Title: Estimation of effects of contact tracing and mask adoption on COVID-19 transmission in San Francisco: a modeling study Content: The current COVID-19 pandemic has spurred concern about what interventions may be effective at reducing transmission. The city and county of San Francisco imposed a shelter-in-place order in March 2020, followed by use of a contact tracing program and a policy requiring use of cloth face masks. We used statistical estimation and simulation to estimate the effectiveness of these interventions in San Francisco. We estimated that self-isolation and other practices beginning at the time of San Francisco’s shelter-in-place order reduced the effective reproduction number of COVID-19 by 35.4% (95% CI, −20.1%–81.4%). We estimated the effect of contact tracing on the effective reproduction number to be a reduction of approximately 44% times the fraction of cases that are detected, which may be modest if the detection rate is low. We estimated the impact of cloth mask adoption on reproduction number to be approximately 8.6%, and note that the benefit of mask adoption may be substantially greater for essential workers and other vulnerable populations, residents return to circulating outside the home more often. We estimated the effect of those interventions on incidence by simulating counterfactual scenarios in which contact tracing was not adopted, cloth masks were not adopted, and neither contact tracing nor cloth masks was adopted, and found increases in case counts that were modest, but relatively larger than the effects on reproduction numbers. These estimates and model results suggest that testing coverage and timing of testing and contact tracing may be important, and that modest effects on reproduction numbers can nonetheless cause substantial effects on case counts over time.

Title: Facemasks prevent influenza-like illness: implications for COVID-19 Content: The coronavirus disease 2019 (COVID-19) pandemic is causing a huge toll on individuals, families, communities and societies across the world. Currently, whether wearing facemasks in public should be a measure to prevent transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) remains contraversial.1 This is largely because there have been no randomized controlled trials (RCTs) for coronavirus to directly support this. However, lessons may be taken from published RCTs examining influenza-like illness (ILI).2,3 Recent studies suggested that SARS-CoV-2 shares similar transmission route with influenza virus,4 and the incidence of community transmission of SARS-CoV-2 in individuals with ILI is high.5 Therefore, we undertook this meta-analysis of RCTs examining the efficacy of wearing facemasks to prevent ILI in community settings, irrespective of confirmatory testing for the causative virus. We undertook a systematic literature search for RCTs related to facemasks and ILI between 1966 and April 2020 using PUBMED, EMBASE, and Cochrane library. RCTs undertaken in community (not hospital) settings comparing wearing and not wearing facemasks for ILI were included. Incidence of ILI (e.g., fever, cough, headache, sore throat, aches or pains in muscles or joints) was estimated per group. Relative risk (RR) and 95% confidence interval (CI) were calculated. We screened 899 related abstracts and eventually included 8 RCTs (Figure S1). Basic characteristics and quality of included RCTs are listed in Supplement. Participants wearing facemasks had a significantly lower risk of developing ILI than those not wearing facemasks (pooled RR=0.81, 95% CI: 0.70-0.95) and there was no heterogeneity (Figure 1). The decreased risk of ILI was more pronounced if everyone wore facemask irrespective of whether they were infected or not (RR=0.77, 95% CI: 0.65-0.91), compared to those wearing facemasks when infected (RR=0.95, 95% CI: 0.58-1.56) or uninfected (RR=1.26, 95% CI: 0.69-2.31). This study shows that wearing facemasks, irrespective of infection status, is effective in preventing ILI spread in the community. This situation mirrors what is happening now in public settings where we do not know who has been infected and who has not. Although there are no RCTs of facemasks for SARS-CoV-2, as with other simple measures such as social distancing and handwashing, these data support the recommendation to wear facemasks in public to further reduce transmission of SARS-CoV-2 and flatten the curve of this pandemic, especially when social distancing is impractical, such as shopping, or travelling with public transport for work that cannot be done from home.

Title: To mask or not to mask children to overcome COVID-19 Content: It has been reported that asymptomatic people can transmit the new coronavirus disease 2019 (COVID-19) and become important sources of COVID-19. To reduce the role of asymptomatic or poorly symptomatic people in COVID-19, universal use of face masks in addition to hand hygiene and safety distance seems extremely useful. Consequently, preparing the healthy child to use face masks is strongly needed. To obtain maximal compliance, reasons for mask wearing without attempts of removing must be clearly explained. Moreover, child's will must not be forced.Conclusion: On the basis of clinical findings, we think that the universal use of facial masks seems necessary when people have to go out in their everyday lives. In addition to the availability of masks of different sizes capable of adapting perfectly to the face, it is necessary that the use of masks in children is preceded by a strong parental work and school lessons on this issue and other hygiene topics with the main aim to obtain child cooperation.What is Known:â¢ Asymptomatic people can transmit and become important sources of COVID-19.â¢ Asymptomatic cases are common also in pediatrics.What is New:â¢ Universal use of face masks for success against COVID-19 seems necessary also in pediatric age when people have to go out in their everyday lives.â¢ In addition to the availability of masks of different sizes capable of adapting perfectly to the face, it is necessary that the use of masks in children is preceded by a strong parental work and school lessons with the main aim to obtain child cooperation.

Title: To mask or not to mask children to overcome COVID-19 Content: It has been reported that asymptomatic people can transmit the new coronavirus disease 2019 (COVID-19) and become important sources of COVID-19. To reduce the role of asymptomatic or poorly symptomatic people in COVID-19, universal use of face masks in addition to hand hygiene and safety distance seems extremely useful. Consequently, preparing the healthy child to use face masks is strongly needed. To obtain maximal compliance, reasons for mask wearing without attempts of removing must be clearly explained. Moreover, child's will must not be forced.Conclusion: On the basis of clinical findings, we think that the universal use of facial masks seems necessary when people have to go out in their everyday lives. In addition to the availability of masks of different sizes capable of adapting perfectly to the face, it is necessary that the use of masks in children is preceded by a strong parental work and school lessons on this issue and other hygiene topics with the main aim to obtain child cooperation. What is Known: â¢ Asymptomatic people can transmit and become important sources of COVID-19. â¢ Asymptomatic cases are common also in pediatrics. What is New: â¢ Universal use of face masks for success against COVID-19 seems necessary also in pediatric age when people have to go out in their everyday lives. â¢ In addition to the availability of masks of different sizes capable of adapting perfectly to the face, it is necessary that the use of masks in children is preceded by a strong parental work and school lessons with the main aim to obtain child cooperation.

Title: Online National Health Agency Mask Guidance for the Public in Light of COVID-19: Content Analysis Content: BACKGROUND: The rapid global spread of the coronavirus disease (COVID-19) has compelled national governments to issue guidance on the use of face masks for members of the general public. To date, no work has assessed how this guidance differs across governments. OBJECTIVE: This study seeks to contribute to a rational and consistent global response to infectious disease by determining how guidelines differ across nations and regions. METHODS: A content analysis of health agency mask guidelines on agency websites was performed in late March 2020 among 25 countries and regions with large numbers of COVID-19 cases. Countries and regions were assigned across the coding team by language proficiency, with Google Translate used as needed. When available, both the original and English language version of guidance were reviewed. RESULTS: All examined countries and regions had some form of guidance online, although detail and clarity differed. Although 9 countries and regions recommended surgical, medical, or unspecified masks in public and poorly ventilated places, 16 recommended against people wearing masks in public. There were 2 countries that explicitly recommended against fabric masks. In addition, 12 failed to outline the minimum basic World Health Organization guidance for masks. CONCLUSIONS: Online guidelines for face mask use to prevent COVID-19 in the general public are currently inconsistent across nations and regions, and have been changing often. Efforts to create greater standardization and clarity should be explored in light of the status of COVID-19 as a global pandemic.

Title: High Filtration Efficiency Face Masks made from Sterilization Wraps Content: COVID-19 pandemic has spawned the need for mass production of N-95 respirators. We used Sterilization Wraps to produce face masks which maintained 93% particle capture efficacy post sterilization. This ubiquitously available material could be explored for production of high quality face masks at a cost less than 30 US cents.

Title: Effectiveness of Cloth Masks for Protection Against Severe Acute Respiratory Syndrome Coronavirus 2 Content: Cloth masks have been used in healthcare and community settings to protect the wearer from respiratory infections. The use of cloth masks during the coronavirus disease (COVID-19) pandemic is under debate. The filtration effectiveness of cloth masks is generally lower than that of medical masks and respirators; however, cloth masks may provide some protection if well designed and used correctly. Multilayer cloth masks, designed to fit around the face and made of water-resistant fabric with a high number of threads and finer weave, may provide reasonable protection. Until a cloth mask design is proven to be equally effective as a medical or N95 mask, wearing cloth masks should not be mandated for healthcare workers. In community settings, however, cloth masks may be used to prevent community spread of infections by sick or asymptomatically infected persons, and the public should be educated about their correct use.

Title: Effectiveness of Cloth Masks for Protection Against Severe Acute Respiratory Syndrome Coronavirus 2. Content: Cloth masks have been used in healthcare and community settings to protect the wearer from respiratory infections. The use of cloth masks during the coronavirus disease (COVID-19) pandemic is under debate. The filtration effectiveness of cloth masks is generally lower than that of medical masks and respirators; however, cloth masks may provide some protection if well designed and used correctly. Multilayer cloth masks, designed to fit around the face and made of water-resistant fabric with a high number of threads and finer weave, may provide reasonable protection. Until a cloth mask design is proven to be equally effective as a medical or N95 mask, wearing cloth masks should not be mandated for healthcare workers. In community settings, however, cloth masks may be used to prevent community spread of infections by sick or asymptomatically infected persons, and the public should be educated about their correct use.

Title: A modelling framework to assess the likely effectiveness of facemasks in combination with 'lock-down' in managing the COVID-19 pandemic Content: COVID-19 is characterized by an infectious presymptomatic period,when newly infected individuals can unwittingly infect others We are interested in what benefits facemasks could offer as a nonpharmaceutical intervention, especially in the settings where high-technology interventions, such as contact tracing using mobile apps or rapid case detection via molecular tests, are not sustainable Here, we report the results of two mathematical models and show that facemask use by the public could make a major contribution to reducing the impact of the COVID-19 pandemic Our intention is to provide a simple modelling framework to examine the dynamics of COVID-19 epidemics when facemasks are worn by the public, with or without imposed 'lock-down' periods Our results are illustrated for a number of plausible values for parameter ranges describing epidemiological processes and mechanistic properties of facemasks, in the absence of current measurements for these values We show that, when facemasks are used by the public all the time (not just from when symptoms first appear), the effective reproduction number, Re, can be decreased below 1, leading to the mitigation of epidemic spread Under certain conditions, when lock-down periods are implemented in combination with 100% facemask use, there is vastly less disease spread, secondary and tertiary waves are flattened and the epidemic is brought under control The effect occurs even when it is assumed that facemasks are only 50% effective at capturing exhaled virus inoculum with an equal or lower efficiency on inhalation Facemask use by the public has been suggested to be ineffective because wearers may touch their facesmore often, thus increasing the probability of contracting COVID-19 For completeness, our models show that facemask adoption provides population-level benefits, even in circumstances where wearers are placed at increased risk At the time of writing, facemask use by the public has not been recommended in many countries, but a recommendation for wearing face-coverings has just been announced for Scotland Even if facemask use began after the start of the first lock-down period, our results show that benefits could still accrue by reducing the risk of the occurrence of further COVID-19 waves We examine the effects of different rates of facemask adoption without lock-down periods and show that, even at lower levels of adoption, benefits accrue to the facemask wearers These analyses may explain why some countries, where adoption of facemask use by the public is around 100%, have experienced significantly lower rates of COVID-19 spread and associated deaths We conclude that facemask use by the public, when used in combination with physical distancing or periods of lock-down, may provide an acceptable way of managing the COVID- 19 pandemic and re-opening economic activity These results are relevant to the developed as well as the developing world, where large numbers of people are resource poor, but fabrication of home-made, effective facemasks is possible A key message from our analyses to aid the widespread adoption of facemasks would be: 'my mask protects you, your mask protects me' [ABSTRACT FROM AUTHOR] Copyright of Proceedings of the Royal Society A: Mathematical, Physical & Engineering Sciences is the property of Royal Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission However, users may print, download, or email articles for individual use This abstract may be abridged No warranty is given about the accuracy of the copy Users should refer to the original published version of the material for the full abstract (Copyright applies to all Abstracts )

Title: The history and value of face masks Content: In the human population, social contacts are a key for transmission of bacteria and viruses. The use of face masks seems to be critical to prevent the transmission of SARS-CoV-2 for the period, in which therapeutic interventions are lacking. In this review, we describe the history of masks from the middle age to modern times.

Title: Potential utilities of mask-wearing and instant hand hygiene for fighting SARS-CoV-2 Content: The surge of patients in the pandemic of COVID-19 caused by the novel coronavirus SARS-CoV-2 may overwhelm the medical systems of many countries. Mask-wearing and handwashing can slow the spread of the virus, but currently, masks are in shortage in many countries, and timely handwashing is often impossible. In this study, the efficacy of three types of masks and instant hand wiping was evaluated using the avian influenza virus to mock the coronavirus. Virus quantification was performed using real-time reverse transcription-polymerase chain reaction. Previous studies on mask-wearing were reviewed. The results showed that instant hand wiping using a wet towel soaked in water containing 1.00% soap powder, 0.05% active chlorine, or 0.25% active chlorine from sodium hypochlorite removed 98.36%, 96.62%, and 99.98% of the virus from hands, respectively. N95 masks, medical masks, and homemade masks made of four-layer kitchen paper and one-layer cloth could block 99.98%, 97.14%, and 95.15% of the virus in aerosols. Medical mask-wearing which was supported by many studies was opposed by other studies possibly due to erroneous judgment. With these data, we propose the approach of mask-wearing plus instant hand hygiene (MIH) to slow the exponential spread of the virus. This MIH approach has been supported by the experiences of seven countries in fighting against COVID-19. Collectively, a simple approach to slow the exponential spread of SARS-CoV-2 was proposed with the support of experiments, literature review, and control experiences.

Title: To mask or not to mask children to overcome COVID-19 Content: It has been reported that asymptomatic people can transmit the new coronavirus disease 2019 (COVID-19) and become important sources of COVID-19. To reduce the role of asymptomatic or poorly symptomatic people in COVID-19, universal use of face masks in addition to hand hygiene and safety distance seems extremely useful. Consequently, preparing the healthy child to use face masks is strongly needed. To obtain maximal compliance, reasons for mask wearing without attempts of removing must be clearly explained. Moreover, child’s will must not be forced. Conclusion: On the basis of clinical findings, we think that the universal use of facial masks seems necessary when people have to go out in their everyday lives. In addition to the availability of masks of different sizes capable of adapting perfectly to the face, it is necessary that the use of masks in children is preceded by a strong parental work and school lessons on this issue and other hygiene topics with the main aim to obtain child cooperation.

Title: Mask crisis during the COVID-19 outbreak Content: On December 31, 2019, the World Health Organization (WHO) reported a cluster of cases of pneumonia of unknown cause detected in Wuhan City, Hubei Province, China. As of February 29, 2020, the National Health Commission of China has reported 79,389 confirmed cases of SARS-CoV-2 infection in 34 provinces. The masks can be used to block respiratory transmission from human to human, and are an effective way to control influenza. It is, therefore, necessary to wear a mask when respiratory infectious diseases are prevalent. China has a population of 1.4 billion. Assuming that two-thirds of the people in China must wear a mask every day, the daily demand for masks will reach 900 million. The Chinese government has taken many measures to solve these problems. Additionally, more measures should be taken to properly dispose of mask garbage. Although the outbreak originated in China, person-to-person transmission of SARS-CoV-2 has been confirmed, which means that it can be spread to anywhere in the world if prevention measures fail. The issues regarding face mask shortages and garbage in China, therefore, deserve worldwide attention.

Title: Mask crisis during the COVID-19 outbreak. Content: On December 31, 2019, the World Health Organization (WHO) reported a cluster of cases of pneumonia of unknown cause detected in Wuhan City, Hubei Province, China. As of February 29, 2020, the National Health Commission of China has reported 79,389 confirmed cases of SARS-CoV-2 infection in 34 provinces. The masks can be used to block respiratory transmission from human to human, and are an effective way to control influenza. It is, therefore, necessary to wear a mask when respiratory infectious diseases are prevalent. China has a population of 1.4 billion. Assuming that two-thirds of the people in China must wear a mask every day, the daily demand for masks will reach 900 million. The Chinese government has taken many measures to solve these problems. Additionally, more measures should be taken to properly dispose of mask garbage. Although the outbreak originated in China, person-to-person transmission of SARS-CoV-2 has been confirmed, which means that it can be spread to anywhere in the world if prevention measures fail. The issues regarding face mask shortages and garbage in China, therefore, deserve worldwide attention.

Title: Face masks for all and all for face masks in the COVID-19 pandemic: community level production to face the global shortage and shorten the epidemic Content: The current COVID-19 pandemic caused a global shortage of medical masks, leaving most exposed health personnel without appropriate protection.Since the beginning of the outbreak, the WHO has revised several times the recommendations on general use of facemasks. In various countries, the public was advised to wear facemasks, in order to ensure them to healthcare workers. Until recently, WHO recommended to limit the use of facemasks to symptomatic people and advised against off-standard solutions. Moreover, recommendations differ among and within countries, causing public confusion and individual initiative.There is wide consensus that universal appropriate use of masks may contribute both to contain the epidemic and to reduce the burden on national procurement, if a community production approach is followed. Especially in low-middle income countries, due to the scarce capacity of national industrial production or import, the use of masks produced at community level may become the only viable option.For the purpose ad hoc guidelines will be needed.Current knowledge and experience call for further and updated review of global and national guidelines in order to provide clear and consistent criteria to ensure the widest availability and appropriate use of facial protection, bearing in mind populations in socio-economic disadvantaged settings.

Title: Face masks for all and all for face masks in the COVID-19 pandemic: community level production to face the global shortage and shorten the epidemic. Content: The current COVID-19 pandemic caused a global shortage of medical masks, leaving most exposed health personnel without appropriate protection.Since the beginning of the outbreak, the WHO has revised several times the recommendations on general use of facemasks. In various countries, the public was advised to wear facemasks, in order to ensure them to healthcare workers. Until recently, WHO recommended to limit the use of facemasks to symptomatic people and advised against off-standard solutions. Moreover, recommendations differ among and within countries, causing public confusion and individual initiative.There is wide consensus that universal appropriate use of masks may contribute both to contain the epidemic and to reduce the burden on national procurement, if a community production approach is followed. Especially in low-middle income countries, due to the scarce capacity of national industrial production or import, the use of masks produced at community level may become the only viable option.For the purpose ad hoc guidelines will be needed.Current knowledge and experience call for further and updated review of global and national guidelines in order to provide clear and consistent criteria to ensure the widest availability and appropriate use of facial protection, bearing in mind populations in socio-economic disadvantaged settings.

Title: The use of facemasks may not lead to an increase in hand–face contact Content: Advocacy of the use of facemasks by the public as a measure against the spread of COVID‐19 is controversial, with some healthcare professionals arguing that the use of a face mask may increase the rate at which people touch their faces, due to readjusting the mask. We assessed the facial touching behaviour of bus passengers in China before and after the outbreak of COVID‐19 and found that wearing a face mask does not increase the number of hand‐face contacts and is likely, therefore, to have a positive beneficial effect on suppressing the spread of COVID‐19 within populations when used in conjunction with social distancing measures.

Title: Mathematical assessment of the impact of non-pharmaceutical interventions on curtailing the 2019 novel Coronavirus Content: A pandemic of a novel Coronavirus emerged in December of 2019 (COVID-19), causing devastating public health impact across the world. In the absence of a safe and effective vaccine or antivirals, strategies for controlling and mitigating the burden of the pandemic are focused on non-pharmaceutical interventions, such as social-distancing, contact-tracing, quarantine, isolation, and the use of face-masks in public. We develop a new mathematical model for assessing the population-level impact of the aforementioned control and mitigation strategies. Rigorous analysis of the model shows that the disease-free equilibrium is locally-asymptotically stable if a certain epidemiological threshold, known as the reproduction number (denoted by [Formula: see text]), is less than unity. Simulations of the model, using data relevant to COVID-19 transmission dynamics in the US state of New York and the entire US, show that the pandemic burden will peak in mid and late April, respectively. The worst-case scenario projections for cumulative mortality (based on the baseline levels of anti-COVID non-pharmaceutical interventions considered in the study) decrease dramatically by 80% and 64%, respectively, if the strict social-distancing measures implemented are maintained until the end of May or June, 2020. The duration and timing of the relaxation or termination of the strict social-distancing measures are crucially-important in determining the future trajectory of the COVID-19 pandemic. This study shows that early termination of the strict social-distancing measures could trigger a devastating second wave with burden similar to those projected before the onset of the strict social-distancing measures were implemented. The use of efficacious face-masks (such as surgical masks, with estimated efficacy [Formula: see text] 70%) in public could lead to the elimination of the pandemic if at least 70% of the residents of New York state use such masks in public consistently (nationwide, a compliance of at least 80% will be required using such masks). The use of low efficacy masks, such as cloth masks (of estimated efficacy less than 30%), could also lead to significant reduction of COVID-19 burden (albeit, they are not able to lead to elimination). Combining low efficacy masks with improved levels of the other anti-COVID-19 intervention strategies can lead to the elimination of the pandemic. This study emphasizes the important role social-distancing plays in curtailing the burden of COVID-19. Increases in the adherence level of social-distancing protocols result in dramatic reduction of the burden of the pandemic, and the timely implementation of social-distancing measures in numerous states of the US may have averted a catastrophic outcome with respect to the burden of COVID-19. Using face-masks in public (including the low efficacy cloth masks) is very useful in minimizing community transmission and burden of COVID-19, provided their coverage level is high. The masks coverage needed to eliminate COVID-19 decreases if the masks-based intervention is combined with the strict social-distancing strategy.

Title: Mathematical assessment of the impact of non-pharmaceutical interventions on curtailing the 2019 novel Coronavirus Content: A novel Coronavirus pandemic emerged in December of 2019, causing devastating public health impact across the world. In the absence of a safe and effective vaccine or antiviral, strategies for mitigating the burden of the pandemic are focused on non-pharmaceutical interventions, such as social-distancing, contact-tracing, quarantine, isolation and the use of face-masks in public. We develop a new mathematical model for assessing the population-level impact of these mitigation strategies. Simulations of the model, using data relevant to COVID-19 transmission in New York state and the entire US, show that the pandemic will peak in mid and late April, respectively. The worst-case scenario projections for cumulative mortality (based on the baseline levels of anti-COVID non-pharmaceutical interventions considered in the study) in New York State and the entire US decrease dramatically by 80% and 64%, respectively, if the strict social-distancing measures implemented are maintained until the end of May or June, 2020. This study shows that early termination of strict social-distancing could trigger a devastating second wave with burden similar to that projected before the onset of strict social-distance. The use of efficacious face-masks (efficacy greater than 70%) could lead to the elimination of the pandemic if at least 70% of the residents of New York state use such masks consistently (nationwide, a compliance of at least 80% will be required using such masks). The use of low efficacy masks, such as cloth masks (of efficacy less than 30%), could also lead to significant reduction of COVID-19 burden (albeit, they are not able to lead to elimination). Combining low efficacy masks with improved levels of other anti-COVID-19 intervention measures can lead to elimination of the pandemic. The mask coverage needed to eliminate COVID-19 decreases if mask-use is combined with strict social-distancing.

Title: Knowledge, Attitude, and Practices of Healthcare Workers Regarding the Use of Face Mask to Limit the Spread of the New Coronavirus Disease (COVID-19) Content: Introduction Many countries including Pakistan are currently using face masks in their pandemic control plans. Being highly prevalent, the correct use of these masks is particularly important, as an incorrect use and disposal may actually increase the rate of transmission. The purpose of this study was to investigate the knowledge, attitude, and practices of healthcare workers (HCWs) in wearing a surgical face mask to limit the spread of the new coronavirus disease 2019 (COVID-19). Materials and Methods This survey was conducted by interviewing HCWs using a questionnaire consisting of the basic demographic characteristics, and the knowledge, attitude, and practices regarding the use of surgical face mask to limit the new COVID-19 exposure. Each correct answer was scored 1 and each incorrect answer scored 0. The total number of questions was 16, and the final score was calculated and then labeled according to the percentage (out of 16) of correct responses as good (>80%), moderate (60-80%), and poor (<60%). Results A total of 392 participants with a mean age of 42.37 ± 13.34 years (341 males and 51 females) were included in the study. The overall final results were good in 138 (35.2%), moderate in 178 (45.4%), and poor in 76 (19.3%). Around 43.6% of participants knew about the correct method of wearing the masks, 68.9% knew that there are three layers, 53% stated that the middle layer act as a filter media barrier, and 75.5% knew the recommended maximum duration of wearing it. The majority (88.2%) of participants knew that a cloth face mask is not much effective, around 79.8% knew that used face mask cannot be re-used, and 44.8% knew about the yellow-coded bag for disposal. Conclusions Knowledge, attitude, and practice of HCWs regarding the use of face masks were found to be inadequate. Studied HCWs had a positive attitude but moderate-to-poor level of knowledge and practice regarding the use of face mask. HCWs and general public awareness campaigns regarding the proper use of face mask by utilizing all social media available resources would be helpful during this pandemic.

Title: Assessment of Fabric Masks as Alternatives to Standard Surgical Masks in Terms of Particle Filtration Efficiency Content: In response to the critical shortage of medical masks resulting from the COVID-19 pandemic, large portions of the population are mobilizing to produce cloth masks using locally-sourced fabrics, however the efficacy of these masks as a means of protecting the wearer from airborne particles carrying virus is not well known. Further, existing protocols are designed for testing the fit and performance N95 respirators and tight-fitting facemasks rather than the relatively more loose-fitting surgical mask style most cloth masks follow. In this study tools and methods typically used to assess tight-fitting facemasks were modified to assess the efficacy of community-produced fabric and commercially-produced surgical masks in terms of protecting the wearer from airborne particles that may be carrying virus. Two TSI PortaCount (model 8028) instruments were operated concurrently to collect particle counts (particles/cm^3) in size range 0.02 to >1 um from ambient air and air just inside the breathing zone of the mask (1 measurement per second, evaluation period of 1 minute per test). Percent particle removal was determined for ten home-made, fabric masks of different designs, with and without filter layers, as well as three commercially-produced surgical-type masks. N95 masks were used to validate the method, and a 3M model 1826 surgical mask was used as a baseline for comparison of other masks of this style. Home-made masks worn as designed always had lower particle removal rates than the 3M masks, achieving between 38% and 96% of this baseline. As has been previously observed by Cooper et al. (1983), adding a layer of nylon stocking over the masks minimized the flow of air around the edges of the masks and improved particle filtration efficiency for all masks, including all commercial products tested. Use of a nylon stocking overlayer brought the particle filtration efficiency for five of the ten fabric masks above the 3M surgical mask baseline. This rapid testing method (<2 hours per mask design) provides a holistic evaluation of mask particle removal efficacy (material, design, and fit), and use of this method for testing a wider range of mask materials and designs will provide the public and health care providers with information needed to optimize health protection given resources at hand.

Title: A RAPID SYSTEMATIC REVIEW OF THE EFFICACY OF FACE MASKS AND RESPIRATORS AGAINST CORONAVIRUSES AND OTHER RESPIRATORY TRANSMISSIBLE VIRUSES FOR THE COMMUNITY, HEALTHCARE WORKERS AND SICK PATIENTS Content: ABSTRACT Background The pandemic of COVID-19 is growing, and a shortage of masks and respirators has been reported globally. Policies of health organizations for healthcare workers are inconsistent, with a change in policy in the US for universal face mask use. The aim of this study was to review the evidence around the efficacy of masks and respirators for healthcare workers, sick patients and the general public. Methods A systematic review of randomized controlled clinical trials on use of respiratory protection by healthcare workers, sick patients and community members was conducted. Articles were searched on Medline and Embase using key search terms. Results A total of 19 randomised controlled trials were included in this study – 8 in community settings, 6 in healthcare settings and 5 as source control. Most of these randomised controlled trials used different interventions and outcome measures. In the community, masks appeared to be more effective than hand hygiene alone, and both together are more protective. Randomised controlled trials in health care workers showed that respirators, if worn continually during a shift, were effective but not if worn intermittently. Medical masks were not effective, and cloth masks even less effective. When used by sick patients randomised controlled trials suggested protection of well contacts. Conclusion The study suggests that community mask use by well people could be beneficial, particularly for COVID-19, where transmission may be pre-symptomatic. The studies of masks as source control also suggest a benefit, and may be important during the COVID-19 pandemic in universal community face mask use as well as in health care settings. Trials in healthcare workers support the use of respirators continuously during a shift. This may prevent health worker infections and deaths from COVID-19, as aerosolisation in the hospital setting has been documented.

Title: [risk Assessment for Aerosol Infection by the New Corona Virus and Protection by Respirators] Content: INTRODUCTION: SARS-CoV-2 is dispersed from patients by talking, coughing and sneezing. The generated micro-droplets aerosols can travel up to 8 meters, stay suspended for long periods and preserve viral infectivity for a median of 2.7 hours. An unprotected person exposed to this cloud, might inhale a considerable amount of infectious viral doses, which will attach to the ACE 2 receptors on alveoli epithelium, resulting in infection. N95 respirators and surgical masks block 95% and 50-60% respectively of inhalable particles and protect the wearer from infection. Surgical masks and N95 without exhalation valve, protect both the wearer and the environment from carriers and sick people.

Title: [RISK ASSESSMENT FOR AEROSOL INFECTION BY THE NEW CORONA VIRUS AND PROTECTION BY RESPIRATORS]. Content: INTRODUCTION SARS-CoV-2 is dispersed from patients by talking, coughing and sneezing. The generated micro-droplets aerosols can travel up to 8 meters, stay suspended for long periods and preserve viral infectivity for a median of 2.7 hours. An unprotected person exposed to this cloud, might inhale a considerable amount of infectious viral doses, which will attach to the ACE 2 receptors on alveoli epithelium, resulting in infection. N95 respirators and surgical masks block 95% and 50-60% respectively of inhalable particles and protect the wearer from infection. Surgical masks and N95 without exhalation valve, protect both the wearer and the environment from carriers and sick people.

Title: Coronavirus infection prevention by wearing masks Content: The coronavirus disease 2019 (COVID-19) [2019-nCoV; severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] was first detected in Wuhan, China at the end of 2019. In current status, spread of CO-VID-19 in person-to-person could be caused mainly by respiratory droplets, which leads to the spread of the influenza virus in both community and clinicians. Thus, in order to reduce the risk of that, the urgent management strategies against COVID-19 are to block transmission, isolation, protection, and using drug or vaccine updated on an ongoing basis. unfortunately, no drugs or vaccines still has yet been allowed to treat patients with COVID-19, so the rapid detection of effective intercessions against COVID-19 is seemed a major challenge on the all world. Herein, this article attempts summarizing to introduce the characterization of COVID-19, the influence of droplets travel in person-to-person transmission and the effect of wearing masks in the infection prevention of influenza virus, as well as understanding its advantage and role in the coronavirus infection prevention.

Title: Importance of face masks for COVID-19 - a call for effective public education Content: Considerable debates about the general community use of face masks for protection against COVID-19 stemmed out from differing views taken by health authorities. Misconceptions and stigmatization towards the use of face masks may hinder the containment of the COVID-19 pandemic. We address this previous debate by analyzing the advice on the community use of masks across different credible health authorities: countries that promoted the use of masks acknowledged that masks are effective, but also explained the importance of their proper use along with other hygiene measures. In contrast, authorities that recommended against the community use of masks mainly cited shortage of supplies, the argument that the public do not have the adequate skills to wear them, or that wearing masks might reduce compliance with other important behaviors. We suggest promoting effective behavioral changes in personal protective measures by teaching microbiological knowledge instead of just listing out the "dos-and-don'ts".

Title: Novel role of plastic wrap in COVID-19. Content: The COVID-19 pandemic is spreading across the world rapidly and poses unprecedented challenges to healthcare systems around the world. It transmits primarily by the droplet route, though surface contact may play an important role as well.1 While people are aware of universal mask-wearing to reduce respiratory droplet transmission, contact transmission, particularly through the indirect contact transmission, is a hidden danger that is often overlooked. There are some sources of non-negligible routes for indirect contact in hospitals, such as the keyboard and elevator buttons often used daily by frontline health workers. However, it is difficult to disinfect these areas thoroughly due to their uneven surfaces. This constitutes a barrier to the precaution of contact transmission.

Title: Mathematical assessment of the impact of non-pharmaceutical interventions on curtailing the 2019 novel Coronavirus Content: A pandemic of a novel Coronavirus emerged in December of 2019 (COVID-19), causing devastating public health impact across the world. In the absence of a safe and effective vaccine or antivirals, strategies for controlling and mitigating the burden of the pandemic are focused on non-pharmaceutical interventions, such as social-distancing, contact-tracing, quarantine, isolation, and the use of face-masks in public. We develop a new mathematical model for assessing the population-level impact of the aforementioned control and mitigation strategies. Rigorous analysis of the model shows that the disease-free equilibrium is locally-asymptotically stable if a certain epidemiological threshold, known as the reproduction number (denoted by âc), is less than unity. Simulations of the model, using data relevant to COVID-19 transmission dynamics in the US state of New York and the entire US, show that the pandemic burden will peak in mid and late April, respectively. The worst-case scenario projections for cumulative mortality (based on the baseline levels of anti-COVID non-pharmaceutical interventions considered in the study) decrease dramatically by 80% and 64%, respectively, if the strict social-distancing measures implemented are maintained until the end of May or June, 2020. The duration and timing of the relaxation or termination of the strict social-distancing measures are crucially-important in determining the future trajectory of the COVID-19 pandemic. This study shows that early termination of the strict social-distancing measures could trigger a devastating second wave with burden similar to those projected before the onset of the strict social-distancing measures were implemented. The use of efficacious face-masks (such as surgical masks, with estimated efficacy ≥ 70%) in public could lead to the elimination of the pandemic if at least 70% of the residents of New York state use such masks in public consistently (nationwide, a compliance of at least 80% will be required using such masks). The use of low efficacy masks, such as cloth masks (of estimated efficacy less than 30%), could also lead to significant reduction of COVID-19 burden (albeit, they are not able to lead to elimination). Combining low efficacy masks with improved levels of the other anti-COVID-19 intervention strategies can lead to the elimination of the pandemic. This study emphasizes the important role social-distancing plays in curtailing the burden of COVID-19. Increases in the adherence level of social-distancing protocols result in dramatic reduction of the burden of the pandemic, and the timely implementation of social-distancing measures in numerous states of the US may have averted a catastrophic outcome with respect to the burden of COVID-19. Using face-masks in public (including the low efficacy cloth masks) is very useful in minimizing community transmission and burden of COVID-19, provided their coverage level is high. The masks coverage needed to eliminate COVID-19 decreases if the masks-based intervention is combined with the strict social-distancing strategy.

Title: Aerosol blocking assessment by different types of fabrics for homemade respiratory masks: spectroscopy and imaging study Content: During the COVID-19 pandemic, there is no agreement, until the current date, about the recommendations of homemade face mask use for the general population, and one of the reasons is a lack of information about their real protective rule on spreading aerosols and viruses. This is a comparative study regarding the relative efficiencies of commercial respiratory masks (medical masks) and homemade fabric masks, which may guide authorities across the globe, following the 'Advice on the use of masks in the context of COVID-19', by the World Health Organization. We described two optical methodologies for charactering respiratory masks. It happens that the aerosol scattering coefficient is linear as a function of its concentration inside the mask chamber. Quantitative optical properties of scattering for a large batch fabrication of masks were demonstrated, making the mask N95 suitable for use as a reference standard.