Three Factors to Consider When Deciding Whether to Mask

Who you are, where you are, and what you’re doing

Dr. Tom Frieden


Photo: Arturo Rey/Unsplash

In the United States, most adults are now fully vaccinated, and hundreds of thousands more people are getting vaccinated every day. Covid case counts are falling, often dramatically, in communities with high rates of vaccination. The risk-level tracker that our group, Resolve to Save Lives, developed with the New York Times now shows many areas of the country in yellow or green — low or moderate risk of Covid — for the first time since the pandemic started.

People have started traveling again, many businesses, schools, and offices have reopened, and large gatherings are being held. In New York City, the Foo Fighters performed for a full-capacity crowd at Madison Square Garden, the first big indoor concert event in the city since March 2020. Along with crowds at baseball games and bars, a semblance of normality is returning.

But as we resume many pre-pandemic activities we’ve sorely missed over the past year, there’s debate about the speed with which public health measures have been loosened and to what extent some — particularly masking — might still need to be followed in our “new normal.” The rapid spread of dangerous variants such as Delta has made the answers to these questions even more complex.

When the CDC loosened its mask guidance — saying that fully vaccinated people can safely remove masks in most places, including indoors and in large groups — many people heralded the move as the beginning of the end of the pandemic. But for others, it’s been confusing. There are conflicting rules at federal, state, and local levels. CDC still recommends that fully vaccinated people wear masks on public transportation and in healthcare facilities. And despite CDC guidance, many businesses still enforce their own mask mandates.

Am I really safe if unmasked and vaccinated? How do I know those around me are all vaccinated? What about the Delta variant? Should I still wear a mask even if the CDC says I don’t have to?

The answer to all of these questions is: It depends. The pandemic is an ongoing threat, and variants remain a risk. Wearing masks significantly reduces spread of Covid, even of variant strains, and different types of masks offer different levels of protection. Here are three factors to consider about masking: who you are, where you are, and what you’re doing.

Who you are

Different people have different risk profiles when it comes to transmitting the virus, getting infected, and getting severely ill.

Are you fully vaccinated?

Once you’re fully vaccinated, you have powerful protection against Covid, including against the Delta variant, and you’re much less likely to spread it to others. But if you’re unvaccinated for whatever reason — you haven’t had the opportunity, you aren’t eligible (children), or you’ve chosen not to — you’re still at risk of getting and spreading infection. And if you’ve only received your first shot of an mRNA vaccine, or got your second shot less than two weeks ago, you’re not yet fully protected.

As I mentioned in a previous Medium piece, one dose of an mRNA vaccine provides 33 percent protection against developing symptomatic Covid disease caused by the Delta variant, compared with 88 percent effectiveness after both doses. Unvaccinated and partially vaccinated people should still wear masks in all public indoor settings.

Are you immunosuppressed?

Based on experience from other vaccines and preliminary data on the effects of immunosuppression and response to Covid vaccines, some people who are immunosuppressed may not be as well protected from infection. These people may want to wear masks to limit risk of infection, particularly when in high-risk settings such as indoor locations with many people present.

The spectrum of immunosuppression is vast, and if you have immunosuppressive conditions or are on immunosuppressive medications, consult with your doctor about whether you may need to take additional precautions to prevent Covid even after being vaccinated. Also, stay tuned to the possibility of better blood tests to check immunity (none are proven to be accurate now) and additional doses of vaccine for immunosuppressed people.

Ironically, with masking becoming much less common, those with immunosuppression may choose to upgrade their mask in crowded indoor settings, using N-95, KN-95, or tightly fitting multilayer masks to provide increased protection.

Do you live with someone at high risk of severe illness?

Those who live, or regularly interact, with people who are immunosuppressed may also need to be especially careful to not get infected and transmit the infection. People living with those who are immunosuppressed should be vaccinated, and, even after vaccination, may wish to be extra careful to avoid even the small chance of breakthrough infection by wearing a mask in high-risk settings. This is one reason the CDC still recommends that staff, patients, residents, and visitors should continue to wear masks in all healthcare facilities.

Where you are

Not all communities have the same level of vaccination coverage. Places that continue to have higher rates of Covid transmission present risks, and travel to or from these areas can lead to spread of disease.

Are you in a setting with high risk of transmission?

In public settings it is difficult to know who is vaccinated. That is why in indoor congregate settings such as hospitals, public transportation, and group homes, the CDC continues to recommend masking, regardless of vaccination status.

Are you in a high incidence area?

In areas where there are high levels of Covid transmission, even fully vaccinated individuals may want to consider wearing a mask in certain situations to prevent the slight chance of breakthrough infection and transmission. This also applies to those who are travelling to places where Covid incidence data may not be reliable or available. To keep yourself and those around you safe and healthy, it’s important to follow CDC and U.S. State Department travel guidance when considering travel, particularly overseas.

Are you in an area with a low vaccination rate?

There is increased risk of Covid spread in counties where vaccination rates are low, but even where vaccination rates appear high, there may be pockets where a number of people are not vaccinated.

When in public settings where people of unknown vaccine status gather indoors, the likelihood of coming into contact with unvaccinated people is higher in communities with lower vaccination rates. Low rates of vaccination will also be found in many international travel destinations outside of the United States and Europe, and in some of those places, data on case rates may not be reliable.

What you’re doing

Different activities bring different risks.

Are you doing an indoor activity that generates a lot of aerosols?

When participating in indoor activities that generate more aerosols through shouting, singing, or hard breathing, consider wearing a mask. This may include time spent inside crowded gyms, at choir practices, or at an indoor sporting event. Wearing a mask in such cases can reduce the small risk of breakthrough infection, especially when the venue is crowded and ventilation is poor. These instances may also include indoor concerts, graduation ceremonies, or religious gatherings.

What’s next?

Masking can help control the spread of other infectious diseases. In the fall and winter months, it’s likely that we’ll encounter others with symptoms due to flu, Covid, or another disease. Wearing a mask doesn’t just have to be a pandemic practice — in many East Asian countries, mask wearing was the social norm even before Covid.

During flu season, it would be quite reasonable for people, especially those who have (or live with people who have) weakened immune systems and pregnant women to wear a mask while on the subway or other crowded places. And let’s hope that there is no stigma against people who choose to do so.

When I was CDC director, I publicly hoped that the culture of wearing masks while sick or when flu or other diseases are in the air might spread to the United States. It’s unfortunate that it took a pandemic to make this possible. But I am glad more people now understand we can use many of the healthy practices that we’ve learned, developed, and normalized during the pandemic to control the spread of diseases ongoing and keep the world healthier.



Dr. Tom Frieden

President and CEO, Resolve to Save Lives | Former CDC Director and NYC Health Commissioner | Focused on saving lives.