FDA advisers recommend updating Covid-19 vaccines for fall boosters.

The FDA's independent advisory panel has recommended that the next round of COVID-19 shots should target the XBB variants, a branch of the omicron variant that has become dominant in the United States. The currently available vaccine is bivalent, targeting both the original strain and the more recent BA.4 and BA.5 omicron variants. The newly chosen target, XBB, is a recombinant virus, and the hope is that a new shot based on one version will provide cross-protection against whichever virus circulates this fall. The potential timeline for distributing the shots varies depending on which strain is chosen by the FDA, with companies able to provide XBB.1.5 vaccines earlier than other options.