The Centers for Disease Control and Prevention on Tuesday advised vaccinated Americans to wear masks in schools and public indoor spaces with high or substantial transmission of the coronavirus, a major reversal of guidance issued two months ago as fears around the delta variant grow.
Officials said they received data that show fully vaccinated people may, in some instances, be able to spread the virus.
They are particularly concerned that children who aren’t eligible for the shots and immunocompromised people who don’t benefit from vaccines will catch the virus and become sick.
Dr. Rochelle Walensky, the CDC director, said the “vast majority” of transmission is emanating from people who are unvaccinated but, “in rare occasions, some vaccinated people infected with the delta variant after vaccination may be contagious and spread the virus to others.”
“This new science is worrisome and unfortunately warrants an update to our recommendations,” Dr. Walensky said.
The CDC recommended that all students return to K-12 school in the fall but said students, teachers, staff and visitors should wear masks. People younger than 12 are not eligible for the COVID-19 vaccines, though clinical trials are underway. Adolescents and teens are eligible for the Pfizer-BioNTech vaccine but the rollout is still ramping up.
It will be up to local districts whether to follow CDC guidance. It’s also unclear whether governors, businesses or local leaders will put teeth behind the mask guidance with new rules or mandates or ignore it, now that most places are promoting vaccination instead of nonpharmacological measures.
High or substantial transmission equates to 50 cases per 100,000 people or more, a standard that 63% of counties in the U.S. meet.
Many states in the South and West have poor vaccination rates and are coded red or orange, meaning the guidance would apply, while places in New England with high vaccination rates tend to have lower transmission, according to the CDC map.
The CDC made waves in May by declaring that fully vaccinated people did not need to wear a mask outdoors or indoors in most settings, enthusing people who got their shots while surprising state officials who were caught off-guard or thought the relaxation was premature.
The new guidance could spark whiplash and confusion among everyday Americans.
“This is not a decision that was taken lightly,” Dr. Walensky said.
Tuesday’s turnabout is also a setback for President Biden, who celebrated the pandemic-recovery effort on July 4 and is now contending with a delta-driven outbreak. Average daily case counts have risen from about 13,000 at the start of the month to over 55,000, the highest levels since April.
The president emphasized the evolving nature of the pandemic and the geographic nature of the new guidance.
“Today’s announcement by the CDC — that new research and concerns about the delta variant leads CDC to recommend a return to masking in parts of the country — is another step on our journey to defeating this virus,” he said. “I hope all Americans who live in the areas covered by the CDC guidance will follow it; I certainly will when I travel to these areas.”
He emphasized that vaccination remains the best way to avoid COVID-19 infection and spread.
The CDC has recorded only 5,914 hospitalizations and 1,141 deaths among the roughly 160 million people who’ve been vaccinated, and many states report that unvaccinated persons account for over 95% of their hospitalizations.
A breakthrough infection becomes more likely, statistically, in places where the virus is swirling at high rates, so federal officials are trying to rein in the spread while promoting vaccination in states where far less than half of the population is protected.
The CDC’s change drew applause from experts who fear the delta variant will spread exponentially in the coming weeks.
“The CDC is right to change its guidance. Sound pandemic management requires tailoring measures to the local situation on the ground,” said Dr. Gavin Yamey, a professor of the practice of global health and public policy at the Duke Global Health Institute.
He said a variety of virus-control measures should be in place until the U.S. can improve its 49% vaccination rate.
“There are a huge number of vulnerable people, including children under 12 who can’t yet get vaccinated and those who are immunocompromised, and the new CDC guidance will help to protect them,” Dr. Yamey said.
But others said officials should focus on promoting vaccination while accepting that there will be mild cases.
“The CDC director and the president have said this is a pandemic of the unvaccinated but yet the vaccinated are being asked to wear masks — both can’t be true. And to what end are we wearing masks for? COVID is not a disease that can be eradicated or limited and we will always have cases,” said Amesh Adalja, a senior scholar at the Johns Hopkins Center for Health Security.
New York Mayor Bill de Blasio, who is resisting a widespread mask mandate, said the city already requires masks in select locations and he’ll have to review the fine print of the guidance.
“The number one tool, the number one weapon, the number one savior is vaccination,” said Mr. de Blasio, a Democrat. “So, we can talk about masks and figure out what makes sense to make — to do about masks. But the thing that will save us is vaccination. The thing that will change the entire environment is vaccination.”
The White House recently said 40% of cases are from three states with relatively low vaccination rates — Florida, Missouri and Texas. Those are Republican-run states that have generally tried to avoid heavy-handed mandates during the pandemic.
Dr. Adalja said “the places where you want people to wear masks, or where vaccination rates are low, are comprised of those individuals unlikely to wear a mask. The solution is the vaccine, not masks.”
The White House said it planned to practice what it preached and use masks on campus, given the level of transmission in the nation’s capital.
“We follow CDC guidance and this afternoon Washington, D.C. was classified as having a substantial level of community transmission,” an official said.
Rep. Cathy McMorris Rodgers of Washington, the top Republican on the House Energy and Commerce Committee, said mask mandates will only breed resentment amid the vaccine push.
She also said the guidance for schoolchildren will be harmful.
“They’ve suffered enough and need to be back in school, in-person, five days a week. Before masks are mandated, public health officials must listen to parents like me who are concerned about the harms of masks to our kids’ mental health and their emotional and social development, especially the harms to young children and those with developmental disabilities,” she said.
The Convention of States Action, a conservative group, released a Trafalgar Group poll on Tuesday that says 63% of Americans do not want the government to take action to address the delta variant, including over 8 in 10 Republicans, half of Democrats and 55% of independents.
Yet federal officials are skittish about viral levels that are starting to tax health systems in places, including a hospital in southwestern Missouri that had to add more COVID-19 wards than it deployed last year.
The average number of hospitalized patients in the U.S. has doubled from about 16,000 at the start of July to 32,000 now.
Previously, the U.S. saw an average of around 58,000 patients during the spring 2020 wave, 73,000 in the Sun Belt summer wave and 136,000 during the peak in January.
The average daily death toll stands at around 275, far less than in previous waves of the pandemic but higher than the 175 reported three weeks ago.
Officials are hopeful the vaccines will keep the country from returning to the darkest days of last year despite the delta challenge.
“Getting vaccinated continues to prevent severe illness, hospitalization and death,” Dr. Walensky said.