Mask guidelines are confusing if you're vaccinated against COVID-19. Experts break down the details.
In the USA, masks are becoming a far less common accessory under federal guidance that once a person is vaccinated, they're largely unnecessary.
But the World Health Organization recommended even vaccinated people continue to wear masks, and Los Angeles health officials suggested this week that all people – vaccinated or not – should wear them inside because of concerns about the delta variant of the virus that causes COVID-19.
So who's right?
It depends on individual circumstances, experts told USA TODAY.
A vaccinated person who isn't immunocompromised is safe going without a mask in the USA, said Dr. Eric Topol, founder and director of the Scripps Research Translational Institute in La Jolla, California.
Vaccines available here are effective against known variants, including delta, said Dr. Monica Gandhi, an infectious disease epidemiologist at the University of California, San Francisco.
The Centers for Disease Control and Prevention said vaccinated people need not mask except when on airplanes, buses or mass transit or in medical settings. Gandhi said that guidance "should not change and is unlikely to change in this country where our cases are still on the decline."
The WHO made a different decision, because its audience is different, she said. It makes recommendations for a planet where less than 10% of the population in many countries has had a single shot.
In places with large outbreaks and few vaccinations, she said, "The vaccinated are more likely to encounter virus and have a breakthrough infection." In some countries, available vaccines may not be as effective as ones here.
"Here in the United States, we're fortunate. We have three vaccines that we know are safe and effective. We have two-thirds of the adult population that is fully vaccinated and really quite protected from the variants that we have circulating here," CDC Director Rochelle Walensky said Wednesday morning on NBC News' Today show.
There may be contexts in which local officials need to make decisions different from national ones, she said.
"There are areas of this country where about a third of people are vaccinated. They have low vaccination rates. And there are areas that have more disease," Walensky said.
"Those masking policies are not to protect the vaccinated, they're to protect the unvaccinated," she said.
In Los Angeles County, officials recommended people mask even after getting their shots, out of concern for the fast-spreading delta variant, which accounts for half the cases there.
"Until we better understand how and to who the delta variant is spreading, everyone should focus on maximum protection," the Los Angeles County of Department Public Health said Monday.
An unvaccinated person is at a higher risk for catching COVID-19 anywhere, but particularly in an environment where infection rates are high, Topol said.
Vaccine effectiveness against hospitalization with delta was similar to that seen with alpha, Gandhi said: 94% after the first dose and 96% after the second with the Pfizer-BioNTech vaccine, which is nearly identical to Moderna's. The Johnson & Johnson vaccine also is quite effective.
“We have every reason to believe … J&J will perform against the delta variant,” Walensky said.
Virtually everyone now hospitalized with COVID-19 in the USA has not been vaccinated.
In a study released Tuesday by the Epic Health Research Network, of more than 8.6 million vaccinated people, 4,260 – or .049% – became infected with COVID-19 and 1,594 were hospitalized with the virus.
Masks reduce COVID-19's spread by about 20% while vaccinations cut it by 90%, said Dr. Roger Chou, an epidemiologist at Oregon Health Sciences University in Portland, who has studied the effectiveness of face masks.
"The more people who get vaccinated, the less likely we're going to have to have people wear masks again," he said
Vaccines are "brilliantly successful" at preventing hospitalization, but they're not as perfect at preventing disease transmission, said Dr. William Schaffner, an infectious disease expert at the Vanderbilt University School of Medicine in Nashville, Tennessee.
People who are vaccinated have a low risk of getting sick themselves and can cut down on the risk of transmitting the virus to someone else by wearing a mask.
"I think that's what LA and WHO are focused on" by recommending mask-wearing, Schaffner said, particularly in light of the delta variant, which is more contagious than other variants.
The USA is not in enough of a crisis situation right now for the CDC to recommend the entire country mask up again, he said.
"They're trying to keep society functioning and don't want revolts," he said.
It may be ironic, he admitted, but most Americans still wearing masks have been vaccinated – like him.
"I don't think there's anything oppressive about wearing a mask," said Schaffner, who wears one routinely as a doctor, but he sees that some people are deeply uncomfortable with them.
People with children too young to be vaccinated might also reasonably decide to keep wearing a mask, said Dr. Clare Rock, a hospital epidemiologist and infectious disease expert at Johns Hopkins School of Medicine.
She has a 6- and a 7-year-old and always masks inside public place with them, both to set an example and to help reduce their risk of catching or passing on an infection.
And if people are particularly anxious about getting infected, there's no reason they shouldn't keep wearing a mask to reduce their anxiety, Rock said. "It's not required for people to remove their masks, it's just that if they're fully vaccinated they have that option."
Schaffner said he will continue to wear a mask in public and avoid large events as a "belt and suspenders" approach to further reducing his own risk of infection and transmission.
Contact Karen Weintraub at firstname.lastname@example.org.
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