A US Food and Drug Administration (FDA) panel of advisors has unanimously recommended that updated COVID-19 vaccines being developed for the autumn vaccination campaign target one of the currently circulating XBB variants.
The Vaccines and Related Biological Products advisory committee (VRBPAC) voted 21 to zero in favour of the monovalent XBB-lineage vaccines, and generally agreed that vaccines targeting the XBB.1.5 subvariant would be preferred.
XBB.1.5, which is another descendant of the Omicron variant, has previously been described as the ‘most transmissible’ subvariant because the mutations it contains allow it to adhere to cells and replicate easily.
The variant accounted for nearly 40% of all COVID-19 cases in the US at the beginning June, according to data from the Centers for Disease Control and Prevention (CDC), with the related XBB.1.16 and XBB.2.3 variants on the rise.
Pfizer/BioNTech, Moderna and Novavax have already started to develop vaccines targeting XBB.1.5 and other currently circulating subvariants.
Kena Swanson, Pfizer’s vice president for viral vaccines, outlined during the advisory meeting that the partners could produce COVID-19 vaccines that target the XBB.1.5 strain by the end of July, pending regulatory sign-off, while Moderna said it was prepared to supply a new variant-containing vaccine in time for autumn.
“The 1.5 looks good. It seems like it’s the most feasible to get across the finish line early without resulting in delays and availability,” said Melinda Wharton, vaccine policy official at the CDC. “The vaccine we can use is the vaccine that we can get. And so it feels like this would be a good choice.”
Selecting XBB.1.5 as the target strain would be particularly beneficial for Novavax as the biotech’s protein-based vaccine takes longer to manufacture than its rivals’ mRNA vaccines.
In a statement published after the meeting, Novavax’s president and chief executive officer, John Jacobs, said: “[The company] expects to be ready for the commercial delivery of a protein-based monovalent XBB COVID-19 vaccine this autumn in line with today’s VRBPAC recommendation.”
The FDA will now consider the panel’s advice as it works towards a final decision on strain selection.