New fall Covid vaccines should goal XBB variants, FDA officers say

Syringe with Covid-19 vaccine against XBB variant. Fight against the virus Covid-19 coronavirus, vaccination and immunization.

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U.S. Food and Drug Administration officials said Monday that updated Covid boosters for the upcoming fall-winter vaccination campaign should target XBB-omicron subvariants.

The US should recommend a monovalent vaccine against XBB.1.5, XBB.1.16 or

FDA staff came to that conclusion ahead of a meeting Thursday where a panel of outside advisers to the agency will recommend a strain for new Covid vaccines to be targeted later this year. There is no fixed date for the start of the vaccination campaign.

Vaccine manufacturers are expected to update their vaccinations once this strain is selected.

Pfizer, Modern And Novavax are already developing versions of their respective vaccines against XBB.1.5 and other circulating variants.

Upcoming strain selection will be critical to these companies’ competitiveness in the fall, when the US is expected to shift vaccine distribution to the private sector. That means all three companies will start selling their updated Covid vaccinations directly to healthcare providers.

The FDA officials’ decision comes weeks after a World Health Organization advisory group recommended that Covid booster shots target XBB variants.

Scientists have said that to date, XBB strains are among the highest immune evasion subvariants.

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According to the FDA, these strains accounted for more than 95% of Covid cases in the US in early June.

They found that the proportion of XBB.1.5 cases is declining, but both XBB.1.16 and XBB.2.3 are “on the rise”.

Last year’s Covid boosters were bivalent, meaning they targeted the original strain of the virus and the Omicron variants BA.4 and BA.5. These variants dominated cases nationwide this past fall and winter.

The recording was slow. Only about 17% of the US population has received the Pfizer and Moderna bivalent booster vaccines since their approval in September, according to the Centers for Disease Control and Prevention.