US FDA advisers back updated Covid-19 vaccine targeting dominant variant

WASHINGTON - Advisers to the United States Food and Drug Administration (FDA) on Thursday unanimously recommended that updated Covid-19 shots being developed for a vaccination campaign in autumn target one of the currently

dominant XBB coronavirus variants.

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

FDA official Peter Marks indicated the agency was likely to settle on XBB.1.5, which manufacturers suggested could be ready for inoculations soonest.

Covid-19 vaccine makers Pfizer-BioNTech, Moderna and Novavax are already developing versions of their respective vaccines targeting XBB.1.5 and other currently circulating subvariants.

Pre-clinical data from all three was presented at the meeting.

“It seems like it’s the most feasible to get across the finish line early without resulting in delays in availability,” Dr Melinda Wharton, vaccine policy official at the US Centres for Disease Control and Prevention (CDC), said of a shot aimed at XBB.1.5.

If XBB.1.5 is chosen as the target for this year’s campaign, it would be especially helpful to Novavax, as its 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.

“The fact that most of the manufacturers are ready to work on XBB.1.5 is an added reason to select this strain or this variant given the immunologic data,” said meeting chair Arnold Monto.

After the meeting, Novavax issued a release saying it expects to be able to deliver its XBB-targeted Covid-19 shot this autumn.

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 US infections, are descendants of the Omicron variant that caused Covid-19 cases to surge to record levels early in 2022.

US health regulators are looking to bring the next Covid-19 shots more closely in line with the circulating virus.

Pfizer, in its presentation, said it could supply its monovalent shots targeting the XBB.1.5 subvariant by the end of July, while Moderna said it was prepared to supply a new variant-containing shot for autumn.

A so-called monovalent, or single target, vaccine would be a change from the most recent bivalent Covid-19 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.

Thursday’s proceedings come after an advisory group to the World Health Organisation in May recommended the next wave of Covid-19 booster shots be updated to target XBB subvariants. Europe’s medicine regulators have also backed that recommendation.

The CDC recommended booster shots broadly in 2022.

But panel member Paul Offit questioned whether the shots needed to be recommended for “everybody every season”, noting that the highest risk groups are those most likely to benefit from an annual booster.

Only about 17 per cent of the US population – some 56.5 million people – received a Covid-19 booster during the 2022 to 2023 vaccination season, according to government data through early May.

Older Americans were boosted at a higher rate than the general population.

Between Moderna and Pfizer, Morningstar analyst Karen Andersen expects 75 million doses to be sold in the US during the 2023 to 2024 campaign.

Moderna in May said it continues to expect the US annual Covid-19 market to be 100 million doses, largely in line with Pfizer’s view of 102 million.

Covid-19 deaths and hospitalisations have declined in 2023, and the US government in May ended its Covid-19 public health emergency, which had allowed millions of Americans to receive vaccines, tests and treatments at no cost. REUTERS