Aiming to bolster defenses against the still-evolving and prevalent coronavirus, federal health advisers said Thursday that the upcoming COVID-19 vaccine will be updated to target the now-dominant XBB strain. said it should.

The unanimous recommendations of the U.S. Food and Drug Administration’s Vaccine Advisory Committee follow those of agency officials, who wrote in a memo that although older vaccine formulations were effective in preventing serious illness, they were “preventive.” The effect wears off over time, making it less protective against subsequent waves of mutants.” virus. ”

The data suggest the use of a more recent dominant coronavirus strain that more closely matches the currently circulating Omicron sublineage, “justified for the 2023-2024 vaccination campaign,” FDA staff said. added.

“I think we need a better vaccine. Dr. Eric Rubin said:

The committee’s recommendations will be considered by the FDA. The U.S. Centers for Disease Control and Prevention is also expected to consider the matter, and the Advisory Committee on Immunization Practices is set to discuss a new coronavirus vaccine on June 23.

Virtually all versions of the coronavirus currently circulating in the United States are descendants of the original Omicron variant that swept across the country in late 2021 and early 2022. Among them, however, the XBB family, which includes XBB.1.5 and XBB.1.16, informally referred to as “,” dominates to the point where “Kraken” and “Arcturus,” respectively, are near monopoly.

according to latest quote According to the CDC, the XBB substrain accounts for nearly 99% of coronaviruses circulating in the United States, replacing the BA.5 subvariant that dominated the country for much of the last year.

“Accumulating evidence suggests that vaccine formulations that more closely match the circulating virus strain can significantly improve vaccine-induced immunogenicity and protection,” FDA staff said.

“It’s a great idea to develop a vaccine based on what’s currently in circulation,” said Dr. Peter Chinhong, an infectious disease expert at the University of California, San Francisco, in an interview. “And XBB is the main game in town. It’s been around for a while. It will probably continue to dominate.”

Given the recent pattern last year, the coronavirus is evolving in a more gradual manner, Qinghong said. So choosing vaccine regimens based on the currently dominant subvariant may still be useful through the fall and winter, when some officials and experts expect some recovery, he said. Said expensive.

The FDA panel said the latest vaccine, announced in September 2022, will focus on XBB rather than a “bivalent” booster that protects against both the Omicron submutant and ancestral coronavirus strains that were prevalent at the time. agreed that it should be a “monovalent” vaccine.

Scientists say future vaccine iterations won’t need to protect the ancestral strain.World Health Organization Technical Advisory Group said in May The original version of the coronavirus that originated in Wuhan, China, at the end of 2019 is essentially extinct, so there’s no need for that anymore.

In the United States, XBB.1.5 accounted for the majority of circulating viruses in early spring, but is now estimated to account for about 40% of specimens, CDC figures show. The emerging he XBB.1.16 is growing in power and is now estimated to account for 18% of his number infected nationwide.

In Los Angeles County, XBB.1.5 accounted for 66% of samples analyzed as of early May.

While this winter hasn’t been as devastating as the first two winters of the pandemic, the US and California are still seeing rising numbers of coronavirus-positive hospitalizations and significant deaths. From October to early June, about 75,000 deaths from COVID-19 have been reported nationwide. That’s more than double the average annual death toll from flu in the decade before the COVID-19 pandemic.

There is a growing consensus about the value of regular updates of the COVID-19 vaccine.

“New formulations of COVID-19 vaccines should aim to induce neutralizing antibody responses in XBB progeny, especially to improve protection against symptomatic disease,” said a WHO advisory group.

And depending on how the coronavirus continues to evolve, the vaccine may need to be re-prescribed.

“This is not going to be the final formulation of this vaccine,” said Dr. Peter Marks, FDA’s vaccine director. “Maybe we’ll need another update at some point.”

However, in terms of considering vaccine formulations in the near future, the WHO Advisory Group noted that XBB.1.16 has very small genetic and antigenic differences from XBB.1.5. “Both spike antigens in these lineages are genetically and antigenically very closely related, with only two amino acid differences between them.”

Officials say updating vaccination regimens ahead of last fall/winter season helped.

“According to observational data, [last year’s updated] The 2019-nCoV vaccine offers improved protection against 2019-nCoV infections caused by Omicron substrains, including the BA.4/BA.5 substrain, compared to the original vaccine,” FDA staff said in a statement. Stated.