In less than two weeks, you could walk out of a pharmacy with a next-generation COVID booster in your arm. Just a few days ago, the Biden administration indicated that the first updated COVID-19 vaccines would be available shortly after Labor Day to Americans 12 and older who have already had their primary series. Unlike the shots the U.S. has now, the new doses from Pfizer and Moderna will be bivalent, which means they’ll contain genetic material based both on the ancestral strain of the coronavirus and on two newer Omicron subvariants that are circulating in the U.S.
These shots’ new formulation promises some level of protection that simply hasn’t been possible with the original vaccines. “A bivalent vaccine will have some benefit for almost everybody who gets it,” Rishi Goel, an immunologist at the University of Pennsylvania, told me. “How much benefit that is, we’re still not exactly sure.” People who aren’t at high risk could end up only marginally more protected against severe outcomes, and no one thinks the shots will banish COVID infections for good. There is, however, a simple rule of thumb that nearly everyone can follow to maximize the uncertain gains from a shot: Wait three to six months from your last COVID infection or vaccination.