The U.S. Food and Drug Administration (FDA) said on Friday it has advised manufacturers that are updating their COVID-19 vaccines to develop monovalent shots to target the XBB.1.5 subvariant.

So-called monovalent, or single-target vaccines, would be a change from the most recent bivalent COVID boosters that targeted both the original and Omicron strains of the coronavirus.

The FDA's advice comes a day after its panel of experts unanimously recommended that the updated COVID shots being developed for a fall vaccination campaign target one of the currently dominant XBB coronavirus variants.

COVID vaccine makers Pfizer/BioNTech, Moderna and Novavax are already developing versions of their respective vaccines to target XBB.1.5 and other currently circulating subvariants.

Novavax's XBB.1.5 COVID vaccine candidate is being manufactured at commercial scale, with plans for it to be in the market for the fall campaign, the company said on Friday.

(Reporting by Raghav Mahobe in Bengaluru; Editing by Pooja Desai)