New federal mask guidelines are supported by science, MUSC expert says

May 14, 2021
Photo illustration shows a crumpled mask on top of a vaccination card and a box of masks in a trash can.
Photo illustration by Sarah Pack

New federal guidelines that say fully vaccinated Americans don’t need to wear masks or physically distance in most situations are backed up by sound scientific evidence. That’s according to the leader of the Medical University of South Carolina’s COVID-19 Epidemiology Intelligence Project.

“Several very large, extremely high-quality studies clearly show that the risk of vaccinated people getting infected is extremely small,” said Michael Sweat, Ph.D.

“When vaccinated people do get infected, they have very mild cases, typically with no symptoms. Meanwhile, other studies show that vaccinated people aren’t likely to transmit the coronavirus to others.”

Dr. Michael Sweat 
Dr. Michael Sweat

Sweat said the change in federal guidelines is timely. “It’s becoming clear that masks for those who are vaccinated make no difference. I believe that we would have soon seen that vaccinated people would realize this and come to realize that it was just performative. They would ask themselves, 'Why am I inconveniencing myself with a behavior that doesn’t have any utility?’ And in addition, they might say, ‘Why should I do this to protect people who will not wear a mask or get vaccinated?’”

But Sweat, director of the MUSC Center for Global Health and a professor in the College of Medicine, said some people may have a trouble with the change — despite being fully vaccinated. “Those who have really toed the public health line and showed solidarity with community concerns by wearing masks may have a difficult transition to not wearing masks.”

There are a few reasons for that, he said. “Mask use is a signal that you care about others. And second, the fear of infection has now become deep rooted. Not wearing a mask will make people who are vaccinated feel like others will think they’re selfish, and there will be a lingering sense of fear of infection. Same with institutions that have mandated masks. It partially signals that they’re responsible institutions, and it’ll be hard to change based on that.”

But another change the new guidelines may bring about may be all too easy for some people – and potentially harmful. “What may happen as vaccinated people stop using masks is that the unvaccinated will do the same thing in droves. And when unvaccinated people stop wearing masks, that will likely drive up the rates of infection among that group. This is also now against the backdrop of the British variant being the dominant strain. So we should expect a possible surge coming – hopefully not huge.”

Sweat said everyone who can get vaccinated should go ahead and get the shots, citing several reasons:

  • Vaccines reduce the severity of, hospitalization rates related to, and mortality from COVID-19. 
  • Vaccines are highly effective against the current variants in circulation.
  • Vaccines work well for all age groups, while natural immunity from a coronavirus infection has been shown to be much less effective among people 65 and older.
  • Many people mistakenly think they had COVID-19 in the past. If they avoid vaccination because of this, it’s very risky.

Sweat’s team will keep an eye on the coronavirus’ trajectory as restrictions ease. It posts daily updates on COVID-19 cases in the Charleston area and weekly updates on everything from the weekly change in reported infections to hospitals’ capacity to treat critically ill patients.

The latest weekly update shows the number of reported infections in Berkeley, Charleston and Dorchester counties combined dropped a whopping 44% compared with the previous week.

“These very large declines in the case rate we are seeing signals that vaccination is driving down the number of people getting infected, and that is something we have all been waiting for,” Sweat said.

“However, people who have not been vaccinated should be aware that these rates we report on are for the entire population, including the majority who now are immune to COVID-19. Virtually all of the new infections are occurring among those without immunity, so it’s still not so safe for those who have not gotten a vaccination.”

Get the Latest MUSC News

Get more stories about what's happening at MUSC, delivered straight to your inbox.