Why Fully Vaccinated People Everywhere Still Need Masks Indoors

The CDC now recommends that vaccinated people almost everywhere wear masks in indoor public places. Here's why it's a good idea.

Keeping up with Covid-19 updates

Thanks to the rapidly spreading Delta variant, and waning immunity from earlier vaccines, it’s still mask season in the United States—even for fully vaccinated people located in just about any part of the country.

“The guidance in this situation and evidence that we have about mask-wearing has really evolved as the Delta variant has taken off,” says Jennifer Balkus, PhD, assistant professor of epidemiology at the University of Washington School of Public Health. “[Masks are] an incredibly important and easy and accessible tool to use. There’s no doubt about their efficacy.”

The Centers for Disease Control and Prevention (CDC)  recommends that fully vaccinated people wear masks in public, indoor settings only in areas of the country with “substantial or high transmission” rates.

However, 97 percent of the country is now considered to have a substantial or high transmission rate, according to the CDC’s Covid Data Tracker (as of September 10, 2021). That means that effectively, if you are fully vaccinated, you should be wearing a mask in indoor public places no matter where you are located.

The mask recommendation never went away for people who are unvaccinated, so if you are not vaccinated and age 2 or older, you should be wearing a mask in indoor public places.

Here’s what we know right now about mask-wearing for fully vaccinated people.

CDC Covid Transmission Rates 9 10 2021
CDC COVID Data Tracker: County by country transmission rate of Covid-19 as of September 10, 2021

Covid-19 cases are soaring

Covid cases are surging, especially in areas with higher percentages of unvaccinated people like Florida, Mississippi, and Tennessee.

More Covid-19 hospitalizations occurred this Labor Day than last year. The healthcare system in Idaho is so overburdened that officials are now rationing care.

To date, about 40 million people in the U.S. have been infected with SARS-CoV-2, the virus that causes Covid-19.

Even vaccinated people can get infected

The three existing Covid-19 vaccines are still effective against the Delta variant, but not quite as effective as they are against the original strain of the virus.

That means you can get infected and sick even if you’ve had your one Johnson & Johnson shot or your two Pfizer or Moderna shots. These are called breakthrough infections. (You’re considered fully vaccinated two weeks after your last Covid-19 inoculation.)

And while breakthrough infections are usually relatively mild in vaccinated people compared to infections in unvaccinated people, they can be serious.

“Breakthroughs are still a concern,” says Ravina Kullar, PharmD, a fellow of the Infectious Diseases Society of America and adjunct faculty at UCLA David Geffen School of Medicine. “I’ve seen breakthrough infections where people have been hospitalized, and we still don’t know the risk of post-Covid complications.”

Infected vaccinated people can spread the virus

Anyone who tests positive for Covid-19, vaccinated or unvaccinated, can still transmit the virus.

This is true whether or not you have symptoms, says Dr. Kullar. And Delta is way, way more infectious than the earlier strain.

The number of viral particles in an infected person’s nose and throat is more than 1,000 times higher with Delta. Higher viral load means easy spreading.

By one estimate, you only have to be in contact with a Covid-19 infected person for one second to get infected yourself, says Dr. Kullar.

Man at doorway with a sign requesting to wear protective face mask on reopening of shop during coronavirus outbreakmixetto/Getty Images

The vaccine doesn’t fully protect some people

The vaccines don’t work equally well for everybody.

People who have weakened immune systems because they take immunosuppressive drugs after an organ transplant, are undergoing chemotherapy, have HIV/AIDS, or another condition don’t get as much protection.

That’s why the Food and Drug Administration authorized in August a third dose of Pfizer or Moderna for people in this category.

If you are positive for SARS-CoV-2, no matter vaccination status, you could infect someone who has a higher chance of becoming severely ill.

The vaccines become less effective over time

Emerging evidence also indicates that vaccine effectiveness is waning as time passes, says Dr. Kullar.

This is why the White House announced that it would like to start boosters in September on a rolling basis eight months after the first round. That initiative is waiting for a green light from the FDA and the CDC’s Advisory Committee on Immunization Practices.

And don’t forget, the vaccine is not authorized for anyone under the age of 12.

(Here are 7 things you need to know about Covid-19 boosters shots.)

Masks are effective

Multiple studies confirm that masks work to slow Covid-19 infections. No one knows exactly how much, but research indicates the reduction could be as high as 70 percent, 80 percent, or higher.

But you have to have the right mask and wear it correctly.

“The fit of the mask is key, even with a cloth mask,” says Dr. Balkus. That means “ensuring that it’s fitting snugly on the bridge of your nose and under the chin. Not having big gaps is important.”

Surgical and N95 or KN95 masks are good but aim to have at least two layers of fabric cotton or cotton blend, says Dr. Balkius.

“It should be breathable without gaps around the nose and chin,” she says. “What’s comfortable for you is the biggest thing.” You may have to wear them for more than a few minutes.

While surgical masks are disposable, cloth masks are washable, says Dr. Balkus. Ideally, you would wear a new surgical mask in every new mask setting and wash cloth masks after each use. The reality may not be that simple.

“Trying to find that practice balance is the key thing and making sure you’re wearing it,” says Dr. Balkus.

Sources

Amanda Gardner
Amanda Gardner is a freelance health reporter whose stories have appeared in cnn.com, health.com, cnn.com, WebMD, HealthDay, Self Magazine, the New York Daily News, Teachers & Writers Magazine, the Foreign Service Journal, AmeriQuests (Vanderbilt University) and others. In 2009, she served as writer-in-residence at the University of Wisconsin School of Medicine and Public Health. She is also a community artist and recipient or partner in five National Endowment for the Arts grants.