Advisers to the U.S. Food and Drug Administration on Thursday unanimously recommended that updated COVID-19 shots being developed for a fall vaccination campaign target one of the currently dominant XBB coronavirus variants. 

The panel voted 21-0 in favor of XBB-targeted shots and the committee’s discussion indicated that the XBB.1.5 omicron subvariant would be preferred. 

COVID vaccine makers Pfizer, BioNTech, Moderna and Novavax are developing versions of their respective vaccines targeting XBB.1.5 and other currently circulating subvariants. Preclinical data was presented at the meeting.  

If XBB.1.5 is chosen as the target for this year’s campaign, it would be especially helpful to Novavax, as their protein-based vaccine takes longer to manufacture than rival mRNA-based shots. If the FDA chose a different target, Novavax could again find itself playing catch up to rivals. 

FDA staff reviewers in documents released this week said available evidence suggests this year’s shots should target an XBB subvariant. XBB and its offshoots, which now account for most U.S. infections, are descendants of the omicron variant that caused COVID cases to surge to record levels early last year. 

U.S. regulators are looking to bring the next COVID shots more closely in line with the circulating virus.  

A so-called monovalent vaccine would be a change from the most recent bivalent COVID boosters that targeted both the original strain of the coronavirus and omicron.  

The FDA takes recommendations from its outside experts into consideration before making a final decision on composition of the shots. 
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