CDC Director Robert Redfield testified before the Senate this week that face masks are the most important public health tool we have right now. Here's what he meant by that.

By Claire Gillespie
September 18, 2020
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If there’s one thing that’s going to save us from COVID-19 it’s a vaccine, right? It might not be as simple as that. Robert Redfield, head of the Centers for Disease Control (CDC), caused a bit of a stir when he suggested on Wednesday that masks might be more effective than vaccines. 

“I might even go so far as to say that this face mask is more guaranteed to protect me against COVID than when I take a COVID vaccine,” Redfield said when he testified before the Senate Subcommittee on Labor, Health and Human Services, as reported by The New York Times. Redfield also described face masks as “the most important, powerful public health tool we have.” 

There’s a growing body of research that supports both individual mask-wearing and policies requiring universal masking—backing up Redfield’s position. One study, published in BMJ Global Health, found the use of masks in households in Beijing was associated with less spread of COVID-19. Households in which people used masks before the first person to get infected showed symptoms were 79% effective in reducing transmission. Another study, from the nonprofit research institute IZA, found that Germany’s local and regional mask mandates “reduced the cumulative number of registered Covid-19 cases between 2.3% and 13% over a period of 10 days after they became compulsory” and “the daily growth rate of reported infections by around 40%.” 

“The virus requires a means of getting from person to person and there is now data to support the use of masks as a form of source control, especially in those with symptoms,” infectious disease expert Amesh A. Adalja, MD, senior scholar at the Johns Hopkins Center for Health Security in Maryland, tells Health. “As a physical barrier that eliminates the ability of the virus to move from person to person, a mask is highly effective if used consistently.”  

There’s also the point that we don’t know how effective a vaccine will be—and it only needs to be 50% effective to get FDA approval. 

“The first generation COVID-19 vaccines are not expected to render all those who receive it impervious to infection (they won’t be like the current measles vaccine), but to modify illness so that the severity and need for hospitalization is lower,” Dr. Adalja says. “So even among the vaccinated infections will still occur. They will just be less frequent and less severe.” 

An approved COVID-19 vaccine, then, will only be one part of a multi-layered approach. Dr. Adalja thinks we’ll still be advised to wear face masks and practice physical distancing in public when the first vaccines become available. There’s a danger that a vaccine that’s perhaps only slightly more than 50% effective gives people a false sense of security, he adds, and leads to a greater spread of the virus because other precautions aren’t being taken. 

In time, the first generation COVID-19 vaccines will be replaced by vaccines that provide “sterilizing immunity” like the measles vaccine, Dr. Adalja says. This means the immune system will be able to stop the virus from replicating within your body. But nobody knows how long that could take—and it could be several years. 

Last week, two infectious disease experts from the University of California-San Francisco described masking as a “crude vaccine” that would immunize some people against the new coronavirus. Writing in The New England Journal of Medicine, the experts said masking could become a form of “variolation” that would generate immunity and thereby slow the spread of the virus while we wait for a vaccine. Variolation dates back to 1000 BC in India when people were infected with low doses of smallpox to induce a mild form of the disease and prevent the person from being re-infected. 

During his testimony on Wednesday, Redfield said that he expects we’ll have enough vaccine to return to “regular life” by the third quarter of next year (i.e. between July 1 and September 30, 2021). Whether face masks will remain a part of that “regular life” or not, we’ll just have to wait and see.