published Tuesday in the CDC's Morbidity and Mortality Weekly Report, sharing an analysis of responses from more than 12,500 Americans who received an additional dose of either the Pfizer or Moderna vaccine.
At the time of the study, which encompassed data from Aug. 12 to Sept. 19, only a third dose of Pfizer or Moderna’s vaccine was authorized in the U.S.
for people with severely weakened immune systems. On Sept. 23, the CDC endorsed just Pfizer’s booster shot for millions of older and otherwise vulnerable Americans.
The agency looked at responses from 12,591 Americans who had completed the CDC's "V-safe" survey after receiving the third dose.