Since the pandemic first hit the U.S., debate has been raging over how effective wearing a face mask is in protecting against spread of the coronavirus, the question rapidly becoming politicized while official entities, particularly the CDC, initially gave Americans mixed messages. The result has been widespread skepticism about the efficacy of masks. But what does the evidence say? Six months into the crisis, here is the most recent data on the potential protective impact of face masks.
Based on all available data, medical masks offer a significant level of protection against coronavirus. The wearing of homemade cloth face masks, while not as effective as the resources available to medical professionals, could help decrease the spread and infection rate of coronavirus. According to one model from the University of Washington’s Institute for Health Metrics and Evaluations, universal mask wearing could save 66,739 lives by Dec. 1, compared to current projections. An Australian study by CR MacIntyre et al, found that adherence to mask use significantly reduced the infection risk for influenza-like illness, and that, during a severe pandemic, transmission within households could be reduced by widespread mask wearing.
A review of all available studies found that household masks offer a useful level of filtration in the relevant droplet size range and that widespread mask use could significantly decrease both the economic impact and death toll of coronavirus. A study by Anfinrud et al analyzed the excretion of droplets from an individual when speaking and found that a homemade cloth mask reduced the number of droplets emitted by individuals from 360 to near 0 when speaking, suggesting that mask use can significantly decrease infectivity.
A 2013 study found that, when asked to make their own homemade masks, 100% cotton T-shirts were the most effective masks in terms of filtration and fit, with a doubling layer providing further protection, though surgical masks were still preferable. In a study released on Aug. 7 by Duke University, researchers found that some masks or mask alternatives made of thin materials, such as fleece or bandana, offer little protection, with fleece making transmission worse by breaking down large droplets into small particles, which linger in the air longer.
The evidence demonstrating the effectiveness of masks is supported by anecdotal accounts of masks preventing the virus from spreading. On a flight from China to Canada, a symptomatic patient who tested positive for coronavirus infected no other passengers on his flight, in part due to his effective mask use, experts believe. In Missouri, two salon stylists with coronavirus infected none of their 140 clients; effective mask-wearing of both staff and patrons has been credited. These incidents combined with the above data suggest that widespread mask-wearing can significantly reduce the spread and impact of the virus, allowing for faster reopening and a minimization of the virus’s potential impact.
On July 20, President Trump tweeted a photo of himself wearing a mask and described mask wearing as “patriotic,” yet there is still political controversy over mask wearing.
Related: Breaking Down The Most Common Face Coverings Thought To Protect Us From COVID-19
Recently, Sweden’s state epidemiologist, Anders Tegnell, claimed that “with the numbers diminishing quite quickly in Sweden, we see no point in wearing a face mask in Sweden, not even on public transport.” Tegnell was criticized for making this claim due to Sweden having a mortality rate of 56.59 deaths per 100,000 population, worse than the United States and Brazil, according to Johns Hopkins University.
Dr. Rosie Frasso, the program director of public health at Thomas Jefferson University, disagrees with Tegnell. In an interview with Frasso, she told me that “based on the state of the science right now, there’s tons of evidence that confirms mask use as a safe and effective way to reduce the transmission of Covid-19, so I’m afraid the epidemiologist from Sweden is misguided; his advice is inconsistent with the evidence. I’m a scientist; I follow the evidence. One thing that’s important to remember about scientists is that when scientists get new information, they adjust their recommendations. It is unfortunate that this is not true in the political space. If a politician changes their mind, even when new data are available, they’re a flip-flopper.”
When discussing mask use as an effective strategy to combat coronavirus, Frasso said that “we need to stack the strategies to get the most protection, [through a combination of] mask wearing, physical distancing, testing, contact tracing, and isolation. I think that everything needs to be taken into consideration; we need to do it all to stop the spread until we have a vaccine. In the meantime, we need to clear up the confusion about mask use; it is key to combating the spread of this deadly disease.”
Some argue that a drastic shift in mask wearing behavior would require mask mandates. A widely referenced study released in June by Lyu and Wehby analyzed the effects of a mask mandate by looking at Washington, D.C., and 15 states, which required individuals to wear masks in public settings where distances of six feet of social distancing could not be maintained. The study concluded that “requiring face mask use in public could help in mitigating the spread of COVID-19,” finding mandates were associated with a decline in growth rate of 2% over three weeks. Despite being the primary strategy of 20 states during this period, the study found no evidence to suggest a decline in daily Covid-19 growth as a result of employee-only mask mandates, which required close-contact service providers to wear masks when working but not consumers.
Despite the political controversy surrounding masks, a majority of scientific evidence suggests that widespread mask wearing will help in combating coronavirus. Concerns about the violation of individual freedoms and arbitrary enforcement of mandates are widespread, and the ideal scenario is that people would voluntarily wear masks. The evidence suggests that if one hopes to return to work and normal life as quickly as possible, wearing a mask is one of the best ways one can do their part to ensure a fast and prolonged reopening.
Related: Is Herd Immunity An Effective Strategy? Here’s What The Latest Studies Found.
This article has been expanded and revised for clarity.