Walensky also approved booster shots for older Americans over age 65, and adults with underlying medical conditions at least six months after their first series of shots — in line with the advisory panel.

“It is worrisome to me that anybody less than 30 is going to be getting a third dose without any clear evidence that that’s beneficial to them, and with more than theoretical evidence that it could be harmful to them,” said Dr. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and member of the CDC’s Advisory Committee on Immunization Practices (ACIP).

Offit also expressed concern that in overruling the ACIP, Walensky may have damaged efforts to persuade more unvaccinated adults to be vaccinated against COVID.

“It’s not hard to scare people who’ve already gotten two doses that they should get another dose,” Offit said. “I’m sure that you can get them to get 10 more doses.”