Study Finds Masks Protect Wearer, Others Against COVID-19 Infection

It likely is a rare pharmacists who hasn’t been asked at least once if wearing face masks really is necessary to stem the spread of COVID-19. Now, a new study provides some surprising answers. Find out how researchers determined that masks provide substantial protection to wearers – not just those around them -- from infection through novel coronavirus aerosols.

COLLEGE STATION, TX – One of the most contentious issues in the U.S. response to the COVID-19 pandemic is whether wearing masks actually helps curb the spread of the infection or are just government overreach. A new study provides some answers.

A report in PNAS (Proceedings of the National Academy of Sciences) discusses how researchers determined that not wearing a face mask dramatically increases a person's chances of being infected by the COVID-19 virus, as well as infecting others.

The Texas A&M University-led study team examined the risk of COVID-19 infection and how the virus is easily passed from person to person. Analyzing trends and mitigation procedures in China, Italy and New York City, the researchers calculate using a face mask reduced the number of infections by more than 78,000 in Italy from April 6-May 9 and by more than 66,000 in New York City from April 17-May 9.

"Our results clearly show that airborne transmission via respiratory aerosols represents the dominant route for the spread of COVID-19," emphasized lead researcher Renyi Zhang, PhD, of Texas A&M. "By analyzing the pandemic trends without face-covering using the statistical method and by projecting the trend, we calculated that over 66,000 infections were prevented by using a face mask in little over a month in New York City. We conclude that wearing a face mask in public corresponds to the most effective means to prevent inter-human transmission.”

"This inexpensive practice, in conjunction with social distancing and other procedures, is the most likely opportunity to stop the COVID-19 pandemic. Our work also highlights that sound science is essential in decision-making for the current and future public health pandemics,” Zhang added.

Background information in the study notes that various mitigation measures have been implemented to fight the coronavirus disease 2019 pandemic, including widely adopted social distancing and mandated face covering in some areas.

The researchers explain, however, that “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.”

The authors write that their analysis reveals that the difference with and without mandated face covering was central in pandemic trends in the three epicenters. They caution that 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,” according to the study.

The research is especially significant because it underscores the benefit to people wearing a mask ask, as well as others around them.

"Our study establishes very clearly that using a face mask is not only useful to prevent infected coughing droplets from reaching uninfected persons, but is also crucial for these uninfected persons to avoid breathing the minute atmospheric particles (aerosols) that infected people emit when talking and that can remain in the atmosphere tens of minutes and can travel tens of feet," explained Mario Molina, PhD, a Nobel Prize-winning professor at the University of California-San Diego.

"Social-distancing and washing our hands must continue, but that's not sufficient enough protection. Wearing a face mask as well as practicing good hand hygiene and social distancing will greatly reduce the chances of anyone contracting the COVID-19 virus,” Zhang said.

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