Why some people may need a booster shot, especially if they got Johnson and Johnson’s single dose

The CDC is expected to meet on Friday to discuss whether or not a booster shot is necessary. Meanwhile, the San Francisco Department of Public Health will allow people who’ve received the Johnson & Johnson single-dose vaccine to receive the Pfizer or Moderna vaccine. This move has not been approved federally or even locally. 

Other countries are already giving boosters. Israel, Germany, and Russia have approved a third shot for the elderly. Should the U.S. be doing it too?



  • John P. Moore - professor of microbiology and immunology at Weill Cornell Medicine
  • Dr. Christopher Colwell - chief of emergency medicine at Zuckerberg San Francisco General Hospital