The Centers for Disease Control and Prevention on Tuesday updated its face mask guidance for those who are fully vaccinated against COVID-19.
CDC Director Rochelle Walensky said during a news briefing that the agency now recommends that, in areas with “substantial and high transmission” of the virus, fully vaccinated people should wear masks in public indoor settings, including schools, to help prevent the spread of the highly-contagious delta variant.
She said the new data shows that the delta variant behaves differently than other strains of the virus and that in “rare occasions” some vaccinated people infected with it may be able to spread the virus to others.
“This new science is worrisome and unfortunately warrants an update to our recommendations,” Walensky said.
Health officials define substantial transmission as when between 50 and 99.99 new COVID-19 cases per 100,000 people have been reported in the past seven days, while high transmission indicates 100 or more new cases per 100,000 people have been reported in the past seven days.
The CDC breaks down transmission levels by county. You can check your area’s level here. Counties with substantial transmission are marked in orange and counties with high transmission are marked in red.
The CDC guidance says fully vaccinated people may choose to wear a mask regardless of their area’s transmission level, especially if they’re immunocompromised or at “increased risk for severe disease from COVID-19” or if they live with someone who is immunocompromised, at an increased risk or not fully vaccinated.
Fully vaccinated people who know they were exposed to someone with “suspected or confirmed COVID-19” should be tested for the virus three to five days after they were exposed and should wear a mask in public indoor settings for 14 days or until they get a negative test result.
The updated guidance marks a reversal from the recommendations the agency made two months ago that said fully vaccinated Americans could resume their pre-pandemic activities without wearing a face mask or social distancing except where it is required by law.
The CDC recommended that unvaccinated people continue to wear masks and take precautions against the virus.
A person is considered fully vaccinated two weeks after receiving their second dose of the Pfizer or Moderna COVID-19 vaccines or two weeks after receiving the single-dose Johnson & Johnson vaccine.
The updates on Tuesday come as the highly-contagious delta coronavirus variant has been spreading throughout the United States and sparking COVID-19 outbreaks.
Officials met Sunday night to review data on the variant and on COVID-19 cases among fully vaccinated people, or breakthrough cases, a person familiar with the discussion told CNN.
The World Health Organization last month recommended that fully vaccinated people continue to wear face masks when possible because of the delta variant’s increased transmissibility and the risk of serious COVID-19 infection.
Walensky said at the time, however, that those who are vaccinated are safe from the variants, saying that the WHO takes into account countries with very low or nonexistent vaccination rates and that the CDC will leave mask requirements up to individual states.
But Dr. Anthony Fauci, the nation’s top infectious disease expert, told CNN’s “State of the Union” on Sunday that the country is now going “in the wrong direction” in terms of COVID-19 spread and that the number of Americans who are unvaccinated is a “problem.”
The CDC says about 49% of the total U.S. population are fully vaccinated against COVID-19 and about 57% have received at least one dose of a vaccine.
Fauci said recommending that vaccinated Americans wear masks again was under “active consideration” and that local guidelines that already urged mask use among the fully vaccinated were not “incompatible” with CDC recommendations, which leave such decisions up to local authorities.
He has said in the past that any changes in recommendations are based on changing science.
“As a scientist, as a health official, when those data change, when you get more information, it’s essential that you change your position because you’ve got to be guided by the science and current data,” he said on MSNBC last month in response to attacks on changing guidance throughout the pandemic.
Dr. Gavin Yamey, a global health and public policy professor at the Duke Global Health Institute in North Carolina, said in a statement that the CDC is “right to change its guidance.”
“Sound pandemic management requires tailoring measures to the local situation on the ground,” Yamey said. “The U.S. is now experiencing a fourth wave of COVID-19, driven by the delta variant, which is estimated to be twice as transmissible as the original strain of SARS-CoV-2. Communities with low rates of vaccination are seeing major surges in cases and, in these places, wearing masks in indoor public spaces can help to prevent spread of the virus.”