In addition to revising its mask guidance on Tuesday, the Centers for Disease Control and Prevention also quietly updated its testing recommendations for people who are fully vaccinated against the coronavirus.
The agency now advises that vaccinated people be tested for the virus if they come into contact with someone with Covid-19, even if they have no symptoms. Previously, the health agency had said that fully vaccinated people did not need to be tested after exposure to the virus unless they were experiencing symptoms.
“Our updated guidance recommends vaccinated people get tested upon exposure regardless of symptoms,” Dr. Rochelle P. Walensky, the agency’s director, said in an email to The New York Times. “Testing is widely available.”
Fully vaccinated people should wear a mask in public indoor spaces after exposure, the agency said. Three to five days later, they should be tested for the virus.
If the results come back negative, they can stop wearing masks indoors. If results are positive, the infected should isolate at home for 10 days.
The new recommendation came on the same day that the agency recommended that fully vaccinated people return to wearing masks indoors under some circumstances. When levels of community transmission are high, everyone, regardless of vaccination status, should wear masks indoors when they are in public, the agency now says.
The agency also recommended that vaccinated people in close contact with unvaccinated people, including children under age 12, consider wearing masks in public indoor spaces whatever the transmission rates in the local community. In a shift, the agency also recommended universal masking in schools.
For months, the C.D.C. had resisted recommending masks for vaccinated people, even as the highly contagious Delta variant spread and the World Health Organization recommended continued mask wearing.
The change was prompted by new data suggesting that even vaccinated people who are infected by Delta may carry large amounts of the virus and transmit it to others, Dr. Walensky said at a news briefing on Tuesday.
The vaccines provide strong protection against the worst outcomes, however, including severe disease, hospitalization and death.
Apoorva Mandavilli contributed reporting.