The CDC released new guidance July 27 recommending fully vaccinated Americans resume wearing masks indoors in certain regions of the U.S.
The agency's initial guidance in May said Americans who are fully vaccinated against COVID-19 no longer need to wear masks or follow social distancing guidelines in most indoor settings, but still recommended unvaccinated people wear masks.
Now, reports of breakthrough infections among fully vaccinated individuals are increasing — potentially due to the increasing prevalence of the delta variant — and new cases are rising in all 50 states.
In areas with high transmission, the CDC now recommends fully vaccinated Americans wear masks indoors. The agency also suggests everyone in K-12 schools — staff and students alike — wear a mask, regardless of vaccination status and community transmission.
Rochelle Walensky, MD, director of the CDC, said during a July 27 media advisory that the agency's guidance will "continue to follow the science." The guidance was updated after reviewing new science related to the delta variant, Dr. Walensky said.
The delta variant remains the predominant strain in the U.S., accounting for 8 out of every 10 virus samples sequenced nationwide. Recent outbreak investigations find that the delta variant behaves differently than past strains, according to Dr. Walensky. In rare cases, some vaccinated people can get the delta variant and have the same levels of the virus in their bodies as unvaccinated people, meaning they can also spread the infection to others. The vast majority of COVID-19 transmission is still in unvaccinated individuals, Dr. Walensky said.
Americans should look at the CDC's COVID-19 data tracker to determine if they are in a county with high levels of transmission, Dr. Walensky said, adding that community leaders should encourage universal masking and further measures.
"We're still largely in the pandemic of the unvaccinated, which is why we want to double down on people getting vaccinated," Dr. Walensky said.
The CDC director said masking is a temporary measure, while vaccination is the measure that will permanently drive down transmission. The decision was not made lightly, but the data required action, Dr. Walensky concluded.