NBC The updated shots are expected to be distributed as early as September as part of a fall booster campaign.
The Food and Drug Administration said Friday that it was advising drugmakers to update the Covid booster shots to target XBB.1.5, the predominant coronavirus strain in the United States.
The announcement came a day after an advisory committee recommended updating the Covid vaccines to target a circulating strain of the virus.
The FDA’s Vaccines and Related Biological Products Advisory Committee on Thursday voted unanimously in support of tweaking the shots to target an XBB strain, as well as dropping the original coronavirus strain from the formulation. During the meeting, the committee did not make a formal recommendation about which specific XBB lineage to include, though in a discussion after the vote, members expressed a preference for XBB.1.5.
“Based on the totality of the evidence, FDA has advised manufacturers who will be updating their Covid-19 vaccines, that they should develop vaccines with a monovalent XBB 1.5 composition,” the FDA wrote in a release published online Friday.
Drugmakers need enough time to produce and distribute the new shots, which are expected to be used as early as September as part of a fall booster campaign.
Pfizer said it could distribute reformulated doses as early as the end of July, depending on the strain selected. Moderna said it expects to begin shipping updated doses, pending FDA approval, “by the end of the summer.” Novavax said it could have updated doses available in the fall.
It’s still unclear whether the fall is the best time to offer boosters. Covid’s spread has often been erratic over the past three years, without the clear seasonality seen with viruses like the flu.
“This season will be very telling whether Covid settles into a seasonal pattern or not,” Ruth Link-Gelles, a senior epidemiologist at the CDC, said during Thursday’s meeting.
XBB.1.5 accounts for about 40% of all new Covid cases as of Saturday, according to the CDC. It’s followed by XBB.1.16 (also called “Arcturus” on social media) and XBB.1.9.1. While the CDC no longer tracks levels of Covid spreading in communities, data from the agency shows hospitalizations have been trending downward since March.