Do face masks protect: 49 scientific studies explaining their effectiveness

Since the beginning of the historic COVID-19 pandemic, one of the hottest topics of discussion has been about masks. Whether they really help slow the spread of the disease, the publication said. PIX11.

At the start of the pandemic, there was little information to prove or disprove the effectiveness of wearing masks to slow the spread of this particular coronavirus, because obviously COVID-19 was a new disease. In addition, there has been little research on the transmission of respiratory diseases during a global pandemic. COVID-19 is a worldwide catastrophe that has struck suddenly and very aggressively. Naturally, there was little data on the effectiveness of wearing masks in these particular circumstances.

This lack of information may have confused many. But millions in the scientific community have rushed to help the world better understand this disease. They were based on years of data on coronaviruses and infectious diseases. Researchers at all 49 monitoring sites listed below admit that much more data remains to be explored. But they all recognized the effectiveness of wearing masks to some extent in slowing the spread of COVID-19.

Controversy over the mandate to wear masks

The controversy surrounding the mandate for masks in New York is heating up as the delta strain is causing more cases of COVID.

Researchers in one of their analyzes urge people not to draw conclusions when reading the findings: “Various authors justify the rejection of masks for four main reasons. First, they argue that there is limited evidence for their effectiveness. The first argument can be challenged on the ground that lack of evidence is not proof of absence. "

Reasons for mistrust and doubt about the masks include conflicting data from health officials, political bias and cultural misunderstandings. Research has shown that wearing masks was less common in countries where their use to prevent disease was not as common as in others. Like the nature of scientific research, studies challenging the claims of disguise do exist. When analyzing the facts and data, most of the people surveyed for this article seem to have come to the affirmative or that more information is needed.

For the writing of this article, efforts have been made to ensure transparency of publication dates, sources, datasets, and the timing of critical findings regarding the wearing of masks. Where they arose, they were taken into account, and we worked to give them context.

Below you will find 49 studies (some awaiting peer review) that show the effectiveness of wearing masks.

Peer-reviewed research:

1. Researchers (including a CDC physician) analyzed data from 2021 previous studies for an article published in February 10 in the Journal of the American Medical Association. They concluded that wearing a mask significantly reduces spread. They write that a cloth mask can reduce the transmission of exhaled droplets of infected carriers into the air by about 50-70%. In addition, masks have been shown to help prevent large respiratory droplets from being inhaled by uninfected users. Overall, the authors found that the main benefit of wearing a mask is source control. It protects others by reducing the amount of respiratory droplets emitted, rather than the respiratory protection that protects the wearer. Peer-reviewed.
2. Universal use of masks for people in public places is recommended by the authors of the Evidence-Based Review of COVID-19 Face Masks. It was first published in January by the Proceedings of the National Academy of Sciences of the USA. The experts collected data from at least 150 other studies, models and results to draw their conclusion. “The available evidence suggests that the near-widespread use of non-medical masks in public places, combined with complementary public health measures, can successfully bring the spread of the virus to below 1. And if such measures are continued, population spread will decrease.” In addition, they argue that a mask ban could increase US GDP by $ 1 trillion by preventing factory closures. Peer-reviewed.
3. A video experiment using high-speed laser light, published in The New England Journal of Medicine, made droplets of fluid from the mouth look like flashes in the light. On observation, 227 to 347 drops of oral fluid flared up when participants uttered the words “stay healthy” without a mask. When the same phrase was spoken with a mask, "the number of flashes remained close to the background level." Peer-reviewed.
4. The University of Iowa published the study in June 2020 in the medical journal Health Affairs. It showed that more than 200 cases of COVID-000 were averted in May after mandatory mask wearing was introduced in several states. For this experiment, the researchers used data analysis and models to measure prevalence in society before and after the enactment of the mask mandate. The data showed that within 19-1 days after the order was issued, the daily number of calls decreased by almost one percentage point. Within 5 days or more, it dropped to two. Peer-reviewed.
5. A traveler with dry cough symptoms traveled from Wuhan, China to Toronto, Canada wearing a mask, analysts at the Canadian Medical Association Journal reported in April 2020 in response to a February 2020 study. None of the 25 passengers deemed "close" on board the flight contracted the virus. This study found that drip transmission was likely more common than airborne transmission. Peer-reviewed.
6. The study, published in June 2020 in the medical journal The Lancet, analyzed 172 other studies from 16 countries. As a result, it was found that although different masks have different efficacy, in general they result in a "significant reduction in the risk of infection." Peer-reviewed.
7. A study published in the journal Science looked at one key claim from opponents of masks. Masks don't work because they can still allow small amounts of respiratory substances to pass through. However, the study explains that the number of particles that can pass through a mask depends on the environment and the degree of contamination of a particular area. For example, a highly infected group of people in a confined space will cause more particles to enter the space overall, including through a mask. However, face masks have been found to effectively limit the likelihood of COVID-19 transmission. Peer-reviewed.
8. A study published in the International Journal of Nursing Research found that out of 19 randomized controlled trials in communities, masks were effective - even without hand washing. Peer-reviewed.
9. The authors of the Science Advances study found that some masks, especially neck tube masks, can disperse large droplets into smaller, more airy droplets. However, surgical and cotton masks as well as bandanas have been found to cause a reduction in transmission and a significant delay between when they left one person's mouth and their discovery. Peer-reviewed.
10. A concluding article in the medical journal Respirology (based on 10 previous studies and data) says that while questions remain, there are "a number of reasons why wearing masks in public is recommended." The authors noted that while masks protect users from droplets more than airborne particles, studies on the spread of influenza show masks are about 40-95% effective. However, they believe that more information is still needed and conclude that even if cloth masks are inferior to medical ones, they are "definitely better than no masks at all." Peer-reviewed.
11. Models created by the authors of a January 2021 study in the journal Frontiers in Medicine showed that wearing face masks confirmed beneficial results in reducing infection rates. Most importantly, mathematical models showed significant reductions in mortality when mask-wearing coverage of the population was nearly universal. This is true even if the mask types were less effective. Peer-reviewed.
12. An article published in November 2020 in Environmental Pollution magazine states that wearing a mask effectively prevents contact, drip, and possibly airborne transmission of COVID-19. Based on their research through a review of existing data, they urged government officials to further emphasize the importance of masks. Peer-reviewed.
13. An October 2020 study in Extreme Mechanics Letters found that facial tissue coverings, especially multi-layer masks, have over 70% blocking efficiency. The multi-layer fabric was found to retain droplets with an efficiency of more than 94%, which is comparable to the effectiveness of medical masks. Peer-reviewed.
14. A scenario in the journal Nature Medicine predicts what will happen if every US state implements and achieves 95% mask use. This will result in the lowest projected cumulative death toll. Under this scenario, no state achieved a daily death rate of eight deaths per million. According to other projections, even if bans / restrictions were not mandated, "any additional coverage that can be achieved through the use of masks will save lives." Peer-reviewed.
15. Authors of the article "How effective is the mask in preventing COVID-19 infection?" studied the transmission of droplets through different masks in a study published in the journal Medical Devices & Sensors, and ultimately found that wearing masks correctly (despite the different efficacy of different types) can significantly reduce the overall risks of infection and increase protection. Peer-reviewed.
16. Consumer grade masks (cloth, bandana) with modifications can offer protection nearly as good or better than non-N95 medical masks used by professionals. That's according to a study published in December 2020 in JAMA Internal Medicine. The researchers wrote that changing the fit was a major factor in improving efficiency. Peer-reviewed.
17. The Annals of Internal Medicine published a study showing that experts do not have sufficient data to argue that cloth masks prevent respiratory droplets from entering the mask. But there is “compelling” evidence that cloth masks do reduce the penetration of particles from the outside and air and surface contamination. The researchers explain: "Each virus-containing particle left in the mask cannot hang in the air as an aerosol or fall to the surface so that it can later be caught by touch." Peer-reviewed.
18. Although the authors of a review of 74 sources in the December 2020 journal Eurosurveillance on Infectious Diseases decided that more data and research was needed, they ultimately estimated that face masks reduced transmission of diseases by up to 15% in their sample. Peer-reviewed.
19. The authors of this April 2020 study found that there were only 348 COVID-19 cases in Taiwan at the time, and 1114 cases in Singapore. According to a published study on Emerging Infectious Diseases, only Taiwan encouraged the wearing of a mask at the onset of the pandemic. While the researchers say the cut was "small," they believe the cut can still have significant benefits, especially if implemented early. The researchers acknowledge the limitations of the study, stating that a small sample was used and that participants observed “suboptimal” adherence to mask wearing rules. They write: “Taiwan has the foresight to stockpile medical and surgical masks; other countries or regions may now consider this as part of their future plans to tackle the pandemic. ” Peer-reviewed.
20. In a study published in the Journal of Travel Medicine by the University of Oxford, researchers found that although the effectiveness of masks varies by type and shape, cloth masks are suitable for non-medical workers and can prevent transmission, especially at an early stage. The authors argue that the model showed that even if face masks are only 20% effective and only 25% of the population use them, infection will decrease by 30%. Peer-reviewed.
21. In March 2021, the implications of the New York Executive Order of April 2020 were studied. According to the decree, all people must wear masks in public places. At the time, New York City was the epicenter of infections in the United States, according to a study published in the Journal of Urban Health. The results showed that mask use in New York prevented 99 infections and 517 deaths from COVID-7. In addition, the researchers say that if the order had been executed just a week earlier, 978 infections and 19 deaths could have been prevented. Peer-reviewed.
22. This Hong Kong study, published in The International Journal of Tuberculosis and Lung Disease, deplores the lack of support for mask wearing in Western countries. As many Asian countries have adopted and normalized the wearing of masks for decades. Experts cite previous research that disputed the benefits of face masks, especially cloth masks, as they are considered far less effective than surgical masks. The authors argue that although cloth masks are less effective than surgical masks, the difference is about 70% versus 90%. This continues to be a "very significant benefit," they said. Peer-reviewed.
23. The authors of the study, published in December 2020 in the journal Future Microbiology, expressed confidence in their findings about mask fit. Thus, masks significantly reduce the transmission of particles when worn correctly. They write: "Quantifying the most effective and effective face masks (both in size and in tissue) will undoubtedly help stop the spread of not only SAR-CoV-2, but also any diseases spread by respiratory particles." Peer-reviewed.
24. Researchers studied the effectiveness of various materials used to make homemade masks. They found that, as expected, different materials have different capabilities in preventing transmission. The laboratory study was conducted at Sichuan University West China Hospital in Chengdu, China and published in October 2020 by the PLOS One Science Journal Community. The laboratory has tested the filtration of various materials and layers. The study found that while homemade masks did not meet surgical mask standards, filtration efficiency and internal pressure drop did. They write: "... homemade masks from available materials, according to the results of this study, can minimize the likelihood of infection." Peer-reviewed.
25. Simulation scenarios were used in this BMJ-published study from New South Wales, Australia. Bottom Line: When used together, mask wearing, widespread population testing, and contact tracing, masks are effective in controlling transmission of COVID-19. The researchers' predictions and models matched fairly closely with how the number of cases played out in New South Wales. Peer-reviewed.
26. Mathematical models were created from the massive data set for this study, published in Nature Communications. These models found: 1) Even limited distribution of masks providing only 25% protection and containment would lead to significant reductions in mortality rates; 2) Even if only 10% of people used masks that provide 25% protection, the mortality rate would decrease by 5%; 3) If people used homemade masks that provided even 2,5 percent protection and containment, the death rate would drop from 2,26 percentage points to 3 percentage points. The researchers write that in places requiring public wearing of a mask, a 5-XNUMX% reduction in mortality can also be expected. Peer-reviewed.
27. In this study, published in the European Respiratory Journal, experts examined information from several countries. They identified differences in distribution among those who wore the mask and those who mostly did not. They urge lawmakers and residents to abide by mask rules, as they are a favorable alternative to quarantines and prolonged social distancing. The authors write: “We strongly support the use of cloth masks as a simple, cost-effective and sustainable alternative to surgical masks. These are source controls for general use, so N95 disposable surgical masks and respirators can be retained for use in healthcare facilities. " Peer-reviewed.
28. A study published in September 2020 by the Psychological Science Association looked at several previous studies to determine why many people refuse or resist when they believe face masks and social distancing help slow the spread of disease. Researchers who have studied empathy analyzed many previous studies to find out the “what” before figuring out the “why”. Peer-reviewed.
29. Using data from 15 previous studies, in a study published by The Lancet, the experts write: “This study supports the universal use of face masks. Because masks were equally effective in health care settings and in public places, if the type of masks used was taken into account when worn. " The authors acknowledge that surgical masks and N95 masks are more effective than cloth masks. But data shows that wearing masks all over the place can reduce the rate of infection, even if they are moderately effective. In addition, the researchers cite data showing that wearing a mask in homes in Beijing prevents secondary transmission if worn before symptoms appear. Peer-reviewed.
30. The Beijing study featured in # 38 was published in May 2020 by BMJ Global Health. It was attended by 335 people in 124 families in which at least one family member had a confirmed case of COVID-19. The authors found that after nearly a month in the same home, the use of face masks by all family members prior to symptom onset was 79% effective in reducing transmission. Peer-reviewed.
31. Another study is published in the medical journal Emerging Infectious Diseases. It showed that although cloth masks are inferior to surgical masks and should not be used by healthcare professionals, they are a suitable option for use by the general public. Fit to the face and material are key, the researchers write. This indicates to use fabrics with a lot of threads and a fine weave - in addition to several layers of fabric. Peer-reviewed.
32. And researchers at New York University in Abu Dhabi studied mask-wearing resistance in Spain in the early stages of the pandemic. Exploring how attitudes and biases here influence mask-wearing decisions, it was explained that many still resist "... despite growing evidence of the effectiveness of mask use against transmission of respiratory viruses." Based on their research, the authors urged governments to develop programs to improve mask compliance. Peer-reviewed.
33. A Vietnamese study published this year in the Journal of Public Health looks at the use of masks by university students. The researchers noted that Vietnam's strict mitigation policies, especially given its proximity to China, helped reduce the number of cases (about 28 cases per 10 million people). The researchers write that the measures, including the mandatory wearing of masks in public and a monetary fine of about US $ 13, have led to a successful containment of the coronavirus infection. Again, while surgical camouflage is the preferred method, researchers are calling for the use of masks and educating the public on their importance. Peer-reviewed.
34. This study, published in January 2021 in the Journal of Econometrics, used robust models, experiments, and datasets. An analysis was made of how continuing to wear masks during the onset of a pandemic could prevent infections and deaths. They concluded that their analysis “convincingly shows” that face mask mandates have reduced the spread of COVID-19. They explain that if all U.S. states had introduced mandatory camouflage policies on March 14, 2020, the total death toll by the end of May would have been about 19-45% less - or between 19000 and 47000 lives saved. Peer-reviewed.
35. Just last month, a study published on science site PLOS One looked at a "substantial" drop in new cases of COVID-19 when mask bans were launched amid a surge in Melbourne, Australia. Using models and logarithmic data analysis, it is estimated that the use of masks in public places has grown from about 43% to 97%, leading to a sharp decline in the spread of viruses and the emergence of new infections. The authors say they strongly support the use of masks in communities. Peer-reviewed.
36. An article entitled "About Masks and Techniques," published in March in the Annals of Internal Medicine, explored how the way masks are worn and applied affects their effectiveness. The experts examined observational studies and other experiments. They concluded that the use of masks in society, especially if they are widespread, correlates with a reduced risk of COVID-19. They write: "Based on the results of all analyzes, the odds ratio was approximately 0,8, which corresponds to a 20% reduction in cases of infection with SARS-CoV-2 if masks are recommended ... Multiple observational studies have documented the link between mandatory wearing of masks and a decrease in the incidence of COVID 19." Peer-reviewed.
37. An Irish study published in the scientific journal MDPI observed the passage of particles through various mask materials. The degree of filtration, the degree of their porosity and the resistance to air flow (among other factors) were determined. Using mathematical models, statistics, and historical data, they found that masks in general are an effective and necessary tool for the foreseeable future. They explain that as materials evolve, including many existing antimicrobial fabrics, masks will become even more effective. They write: "Modern materials used in production, including non-woven fibrous materials, have been used since the beginning of the twentieth century and, as shown, are still quite effective." Peer-reviewed.
38. A study was conducted in Ethiopia in February 2021 and published in the medical journal Risk Management and Healthcare Policy. Scientists have analyzed the database and other articles about COVID-19. As a result, it was concluded that universal use of face masks can help contain the spread of the virus in the community if masks are used appropriately and are available as needed. Peer-reviewed.
39. Another study published by JAMA in February 2021 examined several other monitors. A table has also been created showing various populations around the world and how their use of masks has impacted distribution. It found, "When masks are worn in combination with other recommended mitigation measures, they protect not only the wearer, but society as a whole." In addition, they explain that as mutations emerge, masks will become even more important. Peer-reviewed.
40. Echoing other findings, the doctor / researcher who prepared the December 2020 Wisconsin Medical Journal review used over 88 scientific references. He summarized his final conclusion that the majority of people wearing masks help control the spread in society. The author notes that while masks can only protect users from infection to a certain extent, they can help control the viral load they are exposed to and, therefore, the severity of their infection. Reviewing.
41. This analysis of medical decision making in May 2021 used models to test the ability of masks to slow the spread of COVID-19 during an initial outbreak or wave. The authors used more than 50 sources. As a result, they determined that even with a moderately effective mask, "it is clear that efficiency has a significant effect on transmission." Researchers recommend wearing masks until at least mass vaccinations have occurred. Peer-reviewed.

Research pending review:

1. The authors of this study conducted several simulations where one infected person was placed in a population of other participants who were susceptible. The wearing of masks by the uninfected gradually increased, and there was a "startling" decrease in the total number of COVID-19 cases. In addition to several other conclusions supporting the effectiveness of the mask, the authors of a study published on MedRxiv, a site linked to Yale University and BMJ, write: “If all people move freely and interact randomly with others (ie 0% SD), the level the daily infection of the population depends on the percentage of people wearing masks. "
2. Researchers at the University of North Texas Health Sciences Center in their July 2020 study found that “states with an early mandate to use masks were able to ward off the June [2020] surge across the country. Here, researchers analyzed data, including daily cases and transmission rates, to determine if local mask wearing requirements influenced the state's prevalence. The surveillance was carried out on four counties in the Dallas-Fort Worth metroplex. The researchers found that in Dallas and Tarrant counties (both had mask mandates), new cases, hospitalizations and emergency room visits dropped sharply. The other two counties, Colleen and Denton, did not have mandates to use masks, which saw either an increase or a slight decrease.
3. A study by the Demographic Research Institute of the Federation of Finnish Families found that wearing masks by 80% of people in the UK reduced the pandemic rate more than a full quarantine.
4. A Malaysian observational study tracked the use of masks by patients admitted to hospitals. They concluded that widespread use of face masks can help mitigate the splash. And more work needs to be done to make sure people are wearing them correctly.
5. The US Environmental Protection Agency (EPA) has tested a variety of face masks. Although efficacy varied, some sheet masks were even better than medical grade masks. All masks have been found to be effective in stopping transmission at a certain level.
6. A study was conducted in school districts in Georgia in late 2020 on the transmission of COVID-19. It found that in schools in the state where masks were required, the incidence of COVID-19 among teachers and staff was 37% lower than in those where there was no requirement to wear masks. The study, published as part of the CDC's Weekly Morbidity and Mortality Report, prompted researchers to recommend the use of masks for both adults and children during offline learning.
7. Researchers at the European Center for Disease Prevention and Control have found that the types of masks offer varying degrees of protection. They said they felt more data was needed, but ultimately recommended wearing masks as a "non-drug intervention."
8. A March study included in the CDC Morbidity and Mortality Weekly Report shows that county-level COVID-19 cases and death rates dropped significantly within 20 days of the imposition of the cloak mandate in that county. The mandates were associated with 0,5 percentage point declines in the first 1-20 days and 1,1-1,8 percentage points between 21-100 days. The researchers strongly recommended the mandatory wearing of a mask in addition to other mitigation measures after their work.
   

   

Withdrawn / Contested Statements:

1. A "research letter" published by JAMA Pediatrics just a month ago was withdrawn due to claims that the authors were unable to confirm their findings. The letter "Experimental Evaluation of Breathing Carbon Dioxide with or Without Face Masks in Healthy Children: A Randomized Clinical Trial," argued that toxic amounts of carbon dioxide were "measured" inside the face masks worn by children. The announcement was promoted by Fox News anchor Tucker Carlson in early July and circulated online. However, the scientific community scrutinized the study before it was ultimately withdrawn.

2. A study by A&M in Texas revealed how COVID-19 is transmitted: Masked people prevented an estimated 66 people from being infected in New York in less than a month. Based on mathematical analysis, they explained that world statistics show: "Wearing masks in public places is the most effective means of preventing transmission of infection between people." This study was twice rejected for peer review due to ambiguous data, assumptions made by researchers, and uncontrolled factors. One colleague who disapproved of the findings wrote that despite "growing evidence" to support the masking recommendations, it is too early to draw conclusions.

3. An April 2020 study published in Annals of Internal Medicine was withdrawn in July 2020. Some data were miscalculated, including data showing that surgical masks were less effective than cloth masks. This may have led readers to believe in the ineffectiveness of surgical masks. Although the researchers asked for the data to be corrected, the editors insisted that the study be canceled.

4. Among the most famous and controversial studies on masks is one of the first conducted during the pandemic. The results, dubbed the Danish Study or DANMASK-19, have been highlighted on social media as proof that cloth and surgical masks do not work. However, the interpretation of its results has been challenged by many, who argued that it ultimately requires "more information" and is "inconclusive." Overall, the protection was found to be limited. Moreover, the study authors also wrote: “[the study] should not be used to conclude that recommending that everyone wear masks in the community will not be effective in reducing SARS-CoV-2 infections because the trial did not test the role of masks in controlling infection sources. SARS-CoV-2 ".

5. Another oft-cited research showing that masks are ineffective was published in the January 2021 issue of the journal Medical Hypotheses, entitled Face Masks in the COVID-19 Era: A Health Hypothesis. The study concluded that masks - both fabric and medical masks - were "ineffective." The study spread on social media, with some claiming to be created by Stanford University and / or the National Institutes of Health. This is not the case, as Stanford Medicine claims to strongly support the use of masks.