The spread of Delta and rising reports of breakthrough infections raise questions about whether the vaccinated might need a “booster” dose. For Americans who received the Pfizer or Moderna mRNA vaccines, that may mean a third shot. For people who got the Johnson & Johnson vaccine, that could mean a second dose of the same vaccine or even an mRNA shot instead.
Some places are already providing additional doses. The San Francisco Department of Public Health is allowing people who got the Johnson & Johnson vaccine to get another dose. Countries like Britain, France, Israel and Germany are giving additional doses to certain groups, like older people and those who have compromised immune systems.
We think “booster” isn’t the right terminology to describe these additional doses because, for many people, the word might imply yearly booster shots, as are given for the flu. We do not believe that everyone will need yearly Covid-19 vaccinations. The crucial questions are whether people are getting the right dosage of vaccine for the best protection and whether multiple doses are better than one.