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Masks and Social Distancing - The Science Behind

On-Site Staff

There has been conflicting information in the media about masks and social distancing being wrongfully imposed on US citizens and interfering with their liberties (1).

Many people don’t believe in the precautions and politics involving this topic, which can prevent evidence from being visible. In light of the recent spike in COVID-19 cases seen across the US, it is vital to look critically at the science behind these two measures recommended by the CDC and WHO (2). Because it is challenging to convey rigorous, controlled studies outside of health care during a pandemic, the current evidence is based on observational and simulation studies (3).

There has been a lot of controversy around wearing masks. Opponents say they have a right not to wear them since the action inhibits their quality of life, while proponents put the health of others as a reason to take this precaution seriously. There is also confusion around if they are successful at preventing infection. Underlining this conflict is the fact that health organizations and political leaders have been inconclusive regarding whether to support wearing masks during the first months of the pandemic. As of now, both WHO and the CDC recommend wearing cloth masks in public (2). According to George Rutherford, the UC San Francisco epidemiologist, the initial hesitation on advising the general public to wear masks could be due to the predicted low prevalence of COVID-19 in the US (which turned out to be false). Another explanation is the attempt to reserve surgical masks for health care workers, which should have been corrected by advisors to promote the use of cloth masks instead (2).

There are significant amounts of evidence supporting the wearing of masks. Masks can successfully prevent small droplets from spreading from an individual who talks or sneezes (4). Collected data has shown that wearing a mask “reduced the risk of infection significantly, ranging from 80 percent among healthcare workers to 47 percent among the general public” (5). Wearing cloth masks, frequent hand washing, and social distancing/isolation are the simplest and cheapest ways of preventing the spread of the virus amongst non-healthcare populations.

Some journalists have expressed the opinion that choosing to wear a mask is a sign of altruism and solidarity (6). It is difficult to mandate wearing a mask on the general population in a democratic, capitalist country, and a lot of politicians are afraid to mandate this among the states for this reason. However, the focus should be shifted toward the importance of preventing the spread of the virus to others, which is a small task everyone can do to help confine the pandemic. Some countries, including the Czech Republic, Canada, and South Korea, advise all citizens to wear masks when in public, and in contrast to the US, it has become a nationwide law (6). In the US, some states mandate and later loosen the law. Loosening mandated health measures has led to spikes in infection rates, causing governors to resort back to the original safety precautions. On top of that, people can travel from one state to another without restrictions on the border, so the virus’s spread is not well controlled.

There are a few mask options noted in the literature. The surgical masks are intended to be worn for single-use, generally in the medical field. The existing research regarding infection preventing masks is based on surgical masks and N-95 masks. The N-95 is another form of nasal protection, but it can stop the droplets from spreading around as well. For the general public, the cloth, homemade, or purchased masks are recommended when in public, where it is difficult to maintain a social distance of six feet or more. Ideally, these should be washed daily with detergent and dried in hot air, and when not in use, they should be stored in a plastic or paper bag, away from children and pets (7).

Because of the recent surge in COVID-19 infections observed in several states (Arizona, Texas, Florida, California, South Carolina), even previously reluctant Republican-leaning states now advise wearing face coverings when in public (8).

Social distancing is different from social isolation. Social distancing refers to maintaining a six-foot distance between people (6) because the transmission of COVID-19 is associated with exposure within three to six feet (one to two meters) of the source (9). Social isolation is defined as the absence of social contacts and interactions (10). There is scarce evidence showing that evaporated droplets released after sneezing can travel and land up to 8 meters from the person (11). It is crucial to remember to practice social distancing, even when a person wears a face covering, as advised by the CDC(12). Social isolation might be implemented more broadly, including closing schools, restaurants, and shops, while leaving open only essential businesses (13). It is a relatively easy and proven tool implemented to keep people far enough away from one another r so the droplets will not reach others and possibly infect them with the SARS-COV-2. This preventative method also includes “no hugs and no handshakes” (13). The social isolation measure to prevent the spread of infection was taken seriously in the first months of the pandemic when states announced their lockdowns of schools and non-essential services. Now, as cities are slowly reopening their regular activities and businesses, and the infection rates are spiking, experts are contemplating whether it was too early. The reopening of restaurants and allowing customers to eat and drink is a major concern, even if it's outside. For example, on 6/30/2020 in the local Boston news, there were pictures from Portland, Maine of people socializing outside of a restaurant, not wearing masks, and not practicing social distancing (14). Only time will show if this will result in an increased number of infections.

1. Does wearing a mask violate our freedoms? Here’s what readers say. [Internet]. Tampa Bay Times. [cited 2020 Jul 1]. Available from:
2. Still Confused About Masks? Here’s the Science Behind How Face Masks Prevent Coronavirus [Internet]. Still Confused About Masks? Here’s the Science Behind How Face Masks Prevent Coronavirus | UC San Francisco. [cited 2020 Jun 30]. Available from:
3. Fong MW, Gao H, Wong JY, Xiao J, Shiu EYC, Ryu S, et al. Nonpharmaceutical Measures for Pandemic Influenza in Nonhealthcare Settings—Social Distancing Measures. Emerg Infect Dis. 2020 May;26(5):976–84.
4. Howard J, Huang A, Li Z, Tufekci Z, Zdimal V, Westhuizen H-M van der, et al. Face Masks Against COVID-19: An Evidence Review. 2020 Apr 12 [cited 2020 Jun 30]; Available from:
5. Chamberlain K. Health officials: Data shows masks, social distancing works [Internet]. The NM Political Report. 2020 [cited 2020 Jul 2]. Available from:
6. Cheng KK, Lam TH, Leung CC. Wearing face masks in the community during the COVID-19 pandemic: altruism and solidarity. The Lancet [Internet]. 2020 Apr 16 [cited 2020 Jun 30];0(0). Available from:
7. Guidance on the Use of Masks by the General Public | IDPH [Internet]. [cited 2020 Jun 30]. Available from:
8. “Wear a Mask!” Republicans Change Tune as COVID-19 Surges [Internet]. Medscape. [cited 2020 Jun 30]. Available from:
9. Infection prevention: Precautions for preventing transmission of infection - UpToDate [Internet]. [cited 2020 Jul 1]. Available from:
10. Prevention I of M (US) D of HP and D, Berg RL, Cassells JS. Social Isolation Among Older Individuals: The Relationship to Mortality and Morbidity [Internet]. The Second Fifty Years: Promoting Health and Preventing Disability. National Academies Press (US); 1992 [cited 2020 Jul 1]. Available from:
11. Bourouiba L. A Sneeze. N Engl J Med. 2016 Aug 25;375(8):e15.
12. CDC. Coronavirus Disease 2019 (COVID-19) [Internet]. Centers for Disease Control and Prevention. 2020 [cited 2020 Jun 11]. Available from:
13. March 13 KP/ P. What is social distancing and how can it slow the spread of COVID-19? [Internet]. The Hub. 2020 [cited 2020 Jul 1]. Available from:
14. Hoey D, Writer RWS. Police find Old Port businesses in compliance after complaints [Internet]. Press Herald. 2020 [cited 2020 Jun 30]. Available from:

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