It's safe to unmask in many places, says the CDC. These experts aren't quite ready

Friday's change in masking guidance from the Centers for Disease Control and Prevention comes as many states and cities across the U.S. are starting to — or already have — ease up on mask mandates.

According to the new CDC metrics, about 70% of the U.S. population lives in a place where they no longer need to wear a mask to protect themselves and others. Their calculation is based on three variables: rates of new cases, new hospital admissions and hospital capacity.

But infectious disease specialists surveyed by NPR say they're not ditching their masks just yet. Many still plan to wear them because they live in a part of the country where the coronavirus is still spreading widely — at least for the time being.

When would they feel comfortable dining in, teaching and grocery shopping sans masks? They shared their personal risk calculations with NPR.

Look for low community transmission — but how low?

The CDC's new emphasis on hospitalization rates is warranted, but that metric isn't necessarily the best guide when considering your individual risk, says Dr. David Dowdy, an epidemiologist at Johns Hopkins University. He and other experts still look at local infection rates when they weigh their personal precautions.

Dowdy says he's vaccinated and boosted and feels well-protected from hospitalization, but he's still trying to avoid catching COVID.

"I just don't want to be out of work. I don't want to be spreading it to my family and making them have to miss work and school," he says. "And so from that perspective, cases actually matter more than hospitalizations"

Dr. Robert Wachter says he's waiting for daily case rates in his community to drop to 10 cases per 100,000 people per day.

"There's nothing magic about the number 10," says Wachter, chair of the department of medicine at University of California, San Francisco. "If someone else prefers 15 or 20, that's fine." He's looking for a number that "implies a lower amount of virus in the community."

In California, where Wachter lives, the rates are currently around 24 per 100,000 people per day and falling. And he is starting to make exceptions to masking up when there is a big enough benefit, which, for him, includes eating at a restaurant indoors.

The number of new cases per capita is also guiding Dr. Ali Khan, dean of the school of public health at the University of Nebraska, in deciding to mask or not.

Khan would like to see about 5 to 10 cases per 100,000 people per day before going mask-free. "My desire was never to have individuals wearing masks forever – it was really to get levels of transmission in the community low enough so that we could be safe," he says. "I don't have a high-risk condition, so I'll be taking off my mask in about two to three weeks when cases get down in my community."

Dr. Lisa Maragakis, senior director of infection prevention at the Johns Hopkins Health System, agrees that she would like to see the case rate "in single digits" before she's comfortable without a mask. She's watching for a daily case rate of 1 to 5 per 100,000 in the rolling 7- to 14-day average.

Daily COVID-19 case rates are not a perfect guideline for taking (or giving up) precautions, Wachter acknowledges, especially as more people use home tests that don't get reported in the national numbers. Still, he says, decreased levels of community transmission are a good signal that "that the system is not being super-stressed; that hospitals are not overwhelmed; that I'll have access to a test and that I might have access to therapies [if needed]."

A trend sustained over time

It's not just about how many cases are being reported, though.

Dr. Abraar Karan, an infectious disease physician at Stanford University, looks at how many tests are coming back positive, what's known as the test positivity rate.

If there is a sustained test positivity rate below 1% — without an uptick — Karan says, "the chance of resurgence or community outbreaks is much, much lower." Test positivity can be found for many counties in the government's Community Profile dataset or on a state health department's COVID-19 dashboard.

"With high community incidence right now, I would not be removing my mask in indoor settings," says Karan of his community.

Cases are falling where Karan lives in California, as they are in much of the U.S. If people start taking off their masks in response and case counts stay low, he says that's an encouraging sign. "We may very well buy ourselves a good spring."

Other health mavens don't have a strict number in mind. "There will come a time where the transmission rate [reaches a plateau] and it's not budging. At that point, I'll just make a decision," says Dr. José Romero, health secretary for the state of Arkansas. Factors he'll consider at that point include how well the vaccines are holding up and whether COVID-19 treatments are widely available.

A permanent accessory — as part of a layered risk strategy

Masking doesn't have to be an all-or-nothing choice.

Even when Romero of Arkansas feels comfortable grocery shopping without a mask, "I'm not sure I'm going to abandon it completely," he says. Like the bottle of hand sanitizer in his backpack, he considers masks just another measure to protect himself, especially during times when the risks are higher.

Masks have become a permanent accessory for Seema Lakdawala, a virologist at the University of Pittsburgh. "It's a really nice complement to the vaccines," she reasons. "If I'm wearing a mask and somebody else in my environment is infected, I'm going to breathe in less virus. Even if I do become infected, the infectious dose would perhaps be low enough that my immunity from vaccination can provide a strong enough barrier and help me recover."

Practically speaking, "If cases are low, maybe I'll go and pop into a store without a mask on," she says, "But I'll keep a mask in my car or in my jacket pocket. And if I want to, I'll just pull it out and put it on."

Consideration for high-risk people and their households

Of course, decisions about masking are personal. They will differ for certain groups, including those at high risk of severe COVID-19, unable to be vaccinated or living with someone who falls into either of those two previous categories.

Though her youngest child is now 6 and vaccinated, Lakdawala says it makes sense for families with young kids to continue to be more conservative about COVID-19 risks. "I do think if I had kids under 5, I would still be very concerned about some of the environments that we would go [to]," says Lakdawala.

For those who are similarly cautious during this transitional period, a high-quality, properly fitted N95 or KN95 mask can provide a substantial amount of protection to the wearer, even if others in a public setting are not wearing a mask. Still, there are places where Maragakis thinks mask requirements for everyone should remain in place.

"We need to understand and take care of the people who are most vulnerable among us by not forcing everyone into situations where they must be in close contact with maskless people."

Maragakis says requiring masks for a while longer would make sense in some settings, including on public transit.

Yuki Noguchi contributed to this report.

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