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The science is clear: Masks worked, but vaccinated people don’t need them now

I believe in masks, but it’s time to move toward normalcy in the United States

A discarded mask in Pacifica, Calif. (Justin Sullivan/Getty Images)

When the Centers for Disease Control and Prevention called for universal mask-wearing to prevent the spread of the coronavirus in April 2020, much of America took heed. We wore masks at work and while jogging. We put face coverings on our children at the playground. And by doing so, we helped slow the spread of a disease that has taken the lives of more than 3.4 million people globally, including more than 580,000 in the United States.

Now, it’s time for us to listen to the CDC again. In declaring last week that most vaccinated people don’t need to wear masks, the agency leaned on solid science that shows the vaccines are working — not only to protect the person who got the shot, but also the people around them. Embracing this new guidance is an important step that will help move our country toward a normality that we’ve all worked hard to bring back.

I am keenly aware of the protective value of masks. I was among the first to publish a scientific brief on the importance of universal face masking for the U.S. public. Since then, I have published many papers with others promoting masks as a way to not only slow the spread of the virus but potentially even reduce the amount of virus the wearer is exposed to and reduce the severity of disease if contracted. Based in part on our work, the CDC revised its guidance in November to conclude that masks don’t just protect others but also protect the person wearing them. Our research also contributed to CDC guidelines early this year that the fit and filtration abilities of the mask make a difference in blocking viral particles, leading many Americans to start double-masking.

So, I am a believer in the power of masks. But the vaccines are even more powerful, according to a growing body of research — not just in clinical trials but in the real world. Study after study has demonstrated that they prevent severe disease and infection at astounding rates. Vaccines prevented covid-19 hospitalization among adults 65 and older by 94 percent, prevented symptomatic infection among health-care workers in Israel by 97 percent and blocked severe covid-19 disease by 97.4 percent in Qatar, even when the majority of circulating virus was from variants of concern, according to studies cited by the CDC the day they released their new mask guidance. Studies also found that serious breakthrough infections among vaccinated individuals are extremely rare. Of over 115 million Americans vaccinated, only 0.0009 percent have had severe covid-19 after vaccination despite the virus continuing to circulate in their communities. Vaccines truly defang the virus.

We now have ample data to show that the vaccines also block transmission. The ability of this virus to transmit from individuals who are infected but do not show symptoms (asymptomatic) has been the reason it was previously so difficult to contain. But multiple studies at this point show us that vaccines massively reduce asymptomatic infection. A March CDC study showed a 90 percent reduction in asymptomatic infections among vaccinated front-line workers, and another study this month shows an 86 percent reduction among vaccinated health-care workers in Israel. Other studies confirm at least an 86 percent to 92 percent reduction in asymptomatic infection after vaccination.

Although some people are still wary of the vaccines, more than half of adults in the United States have now received at least one dose, and cases and hospitalizations have plummeted. Many states are far below the metric that we set out in a Washington Post article in early April for when restrictions could be lifted.

When the CDC rolled out its most recent recommendations on masks last week and President Biden finally told us “we’ll smile again, and now see one another’s smiles,” I, along with many others, agreed that this was a wonderful, data-driven, science-acknowledging day. But others who had hailed the initial recommendation in 2020 to wear face coverings by the CDC as scientifically sound reacted to the new guidance with trepidation and surprise. Some declared that, out of mistrust of the federal agency and their fellow Americans, they planned to continue to wear masks for the foreseeable future and that they saw no harm in doing so.

But there is harm in rejecting this science and the recommendations of a famously cautious CDC. Studies have clearly shown that incentives, including signaling the end of masks and distancing, would increase vaccine uptake among the hesitant. Mask-wearing by the vaccinated is not necessary based on the science, but motivating vaccination among the wary is of tantamount importance. And while the virus rages in countries such as India without access to enough vaccine, the United States has been fortunate. Masks, distancing and ventilation are mitigation strategies; vaccines are the solution. We don’t need to mitigate the impact of the virus by other interventions if we can suppress it through immunization instead.

My biggest concern about failing to embrace the science at this point is that it could prevent the return of full in-person school. The science tells us that, on our current trajectory, it’s possible to get all children back to school in person by the fall — free of masks, regular testing, social distancing or fear. That is not only because adolescents are now approved for the vaccine and a vaccine for the very young could be available by then. Children who are not yet vaccinated have two very strong dynamics working in their favor. First, as is well known, children are at extremely low risk of serious illness from covid compared to adults. Secondly, as case rates fall even lower, children not yet eligible for vaccination will be protected as more in the community become immune. With fewer people infected, the likelihood of any unvaccinated people being exposed to the virus will become vanishingly small.

But science cannot always overcome fear, as we have seen in California, where more than half of students remain in distance learning even though it is the state with the lowest case rates of covid-19 in the nation and among the states with the highest vaccine uptake. Many groups, including the American Federation of Teachers, recognize the need for regular school to resume nationally. If we let fear dominate our narrative now — even with the incredible power of the vaccines and a usually cautious public-health agency embracing that science — the fate of schools in the fall will remain in the balance.

The CDC guidance was celebratory and hopeful, as was Biden signaling this was a “great day for America.” Do not be afraid to follow the science on the CDC’s current mask guidance as you followed the science before vaccines: embrace their effectiveness, accept increasing normalcy, and minimize further collateral damage as we emerge into this brighter and brighter light at the end of the U.S. epidemic’s tunnel.


An earlier version of this story incorrectly described a study on the effectiveness of vaccines. The study found that vaccines prevented hospitalization in 94 percent of adults 65 and over, not in adults over 65.