With the Delta variant of COVID-19 spiraling out of control, the Centers for Disease Control and Prevention on Tuesday recommended that people fully vaccinated against the coronavirus resume wearing face masks in public indoor spaces in COVID-19 hotspots. Everyone in K-12 schools, including teachers, staff and students, are urged to wear masks regardless of vaccination status.
The new guidance is a dramatic reversal from the CDC’s position just two month ago that immunized people don’t need to wear masks indoors. The agency had no plans to change the guidance as recently as last week. But as cases of the Delta variant surged across the country, federal health officials met over the weekend, CNN reported, to review new evidence and discuss revising the guidance.
A key finding that prompted the guidance reversal is that people who are fully vaccinated can still transmit the coronavirus in some cases, CDC Director Rochelle P. Walensky said in a media briefing Tuesday.
“The delta variant is showing every day its willingness to outsmart us,” Walensky told reporters. “In recent days I have seen new scientific data from recent outbreak investigations showing that the Delta variant behaves uniquely differently from past strains of the virus that cause COVID-19…This new science is worrisome and unfortunately warrants an update to our recommendations.”
The Delta variant, first detected in India, has dominated the latest wave of COVID-19 infections globally. In the U.S., 63 percent of counties now have high or substantial transmission of COVID-19, according to CDC data. The number of counties with high transmission rate increased 17 percent over the past week. Nevada, Arizona, Wyoming and a number of Southern states are among the hardest-hit regions.
Meanwhile, vaccination efforts stagnate. As of Monday, only 49 percent of the U.S. population (age 12 and up) were fully vaccinated, according to according to federal data. Sixty nine percent of adults have received at least one dose of COVID-19 vaccine, slightly missing President Joe Biden’s goal to vaccinate 70 percent of American adults by July 4.
The New York Times reported that vaccine providers are currently administering an average 566,000 doses per day. That’s a sharp 83 percent decrease from the peak rate of 3.38 million doses per day in April.
Walensky stressed that the vast majority of transmission is happening among unvaccinated people and that the CDC strong encourages those unprotected to get vaccinated as soon as possible.
Multiple studies have found that the delta variant could escape protection of authorized COVID-19 vaccines. The mRNA-based Pfizer/BioNTech vaccine, for example, is less than 40 percent effective against the delta variant after the first dose, two separate real-world studies in the U.K. and Israel have found. A single dose of the Oxford/AstraZeneca vaccine was only 30 percent effective against delta, the U.K. study found.
However, both studies show that existing vaccines are highly effective (around 90 percent) at preventing severe illness and death inflicted by the Delta variant.