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Covid masks save lives. The CDC says double-masking may save more.

It is time for masks to perform one last heroic act.
Image: New York Snow Enters Record Books As City Starts Digging Out
A pedestrian wearing protective masks holds an umbrella while crossing a street after a winter storm in New York, on Feb. 2, 2021.Mark Kauzlarich / Bloomberg via Getty Images file

The end of routine mask use is coming. Possibly by the end of 2021, and almost certainly by the following summer, SARS-CoV-2 is expected to circulate at much lower levels. Americans will once again safely congregate at restaurants, sporting events, concerts and places of worship without wearing masks. When this time arrives, many people will rejoice, and I will be among them. It will be nice to see friends smile, to breathe freely and to avoid foggy glasses.

However, our memories of masks shouldn't be limited to their hassle factor. A high degree of appreciation, and even reverence, is also in order.

Researchers warn that before we start taking our masks off, we should really think about putting better masks on.

Masks have saved far more lives than any other biomedical intervention for Covid-19. Enormous credit goes to the research teams whose hard work and wizardry resulted in the availability of remdesivir, dexamethasone and neutralizing antibodies to treat SARS-CoV-2 and to the clinicians who identified that stiff Covid-19 lungs function better in people who are lying on their stomachs. Masks operate far upstream of these treatments. To save the most lives in a pandemic, the imperative is to prevent the most infections.

One day it will be a fun challenge for nerds like me to try to estimate whether masks saved more lives than vaccines. But the reality is that by increasing the number of people who will benefit from vaccines, masks have allowed vaccines to save more lives. And this is why researchers warn that before we start taking our masks off, we should really think about putting better masks on.

Many people (notably professional football coaches) struggle to wear masks properly. Even perfectly worn masks can fail. Cloth and hospital mask fibers resemble a loose bamboo forest coated in Velcro. If the viruses happen to hit a branch while floating through, they stick. If not, then it is on to the airway. At a high SARS-CoV-2 viral load (many millions of viruses) it is possible that some viruses will get through, though probably fewer than without masks, which may at least limit the severity of the infection.

Well-fitting N95s bypass these shortcomings by preventing air leakage and presenting a denser thicket of branches through which viruses must travel. But the majority of the public doesn't own N95s. Worse, there has been little clear guidance or guidelines about which masks are more or less effective. The World Health Organization has released some guidelines and the media have published others, but there is very little regulatory oversight to ensure that the masks you buy on Amazon are as effective as possible.

Another option supported by national leaders in mask science is double masking. New data from the Centers for Disease Control and Prevention suggest that double masking can block as many as 90 percent of viral particles if worn properly. As Dr. Anthony Fauci said Jan. 25, "If you have a physical covering with one layer, you put another layer on, it just makes common sense that it likely would be more effective."

Until herd immunity is reached, and as new, more contagious variants begin to circulate, two layers may provide additional protection. Sadly, plenty of Americans aren't wearing even one.

Ashish Goyal and Bryan Mayer in my research group designed a mathematical model that demonstrated that if the percentage of people wearing masks increased by just 25 percent and the effectiveness of masks improved by the same amount, it would easily push the reproductive number below 1, meaning cases would decrease rather than double every week.

Ashish and Bryan also showed that superspreader events, defined as one person infecting five or more other people, drive the pandemic. Therefore, if the most effective available masks were mandated in crowded high-risk indoor work and shopping environments, the virus wouldn't survive in the larger population.

Tragically, masking became politicized in 2020. Messaging was inconsistent. Best scientific practices weren't implemented. Enough people wore masks to limit the scope of our national tragedy, but not enough to prevent it. States with lower mask use predictably fared worse in various ways. No effort was made to systematically provide essential workers with N95 or KN95 masks. A standardization tool to offer the public detailed information about mask effectiveness was never considered. The negligence is hard to fathom.

This takes us to 2021. Several new SARS-CoV-2 variants have emerged in Britain, Brazil and South Africa. These variants are considerably more contagious, which makes them harder to contain. More infections will lead to more hospitalizations and deaths. More contagious viruses will increase the number of people who will have to be infected and/or vaccinated before herd immunity is reached. Vaccine efficacy against the new variants may be lower. We are unfortunately in a very dangerous situation.

We must use every strategy possible to win the race between the new variants and the vaccines. To prevent a massive surge of infections and deaths in the spring and summer of 2021, it is imperative to vaccinate people as quickly as possible. However, we also must slow down our opponent. Now is the time for a national mask mandate and a requirement for federally approved N95 or KN95 masks in crowded indoor environments. It is time for masks to perform one last heroic act.