A Food and Drug Administration (FDA) advisory committee on Thursday raised questions about the shift to an annual Covid booster for most adults and children, saying too many questions remain about the unresponsive virus.

The FDA convened its Advisory Committee on Vaccines and Related Biologicals to discuss how Covid vaccines may change in the future.

On Monday, the agency published information documents proposing annual covid vaccines that target the latest variants of the virus, a similar approach to the annual flu shot.

But during Thursday’s meeting, several committee members said they were worried about making decisions about when to administer the vaccines, since the virus is still so new.

Unlike the flu, which flourishes in the winter months, the spread of covid has often been erratic, constantly mutating into new variants and failing to establish a predictable seasonal pattern. A common refrain at the meeting was that covid was not like the flu.

«We don’t know what’s going to happen,» said Dr. Eric Rubin, editor-in-chief of the New England Journal of Medicine. «It’s hard to say it’s going to be annual right now.»

The virus may mutate several times a year to become more virulent or more immune to evasion, or it may not.

“We may or may not need an annual vaccination,” said Dr. Cody Meissner, a pediatrician at Tufts University School of Medicine. «It’s too early, I think, in this process to answer that.»

Other committee members said they were concerned about the amount of protection people would have against the virus if the US switched to an annual vaccination schedule, and whether it would be better to wait for more effective vaccines.

Thursday’s meeting included a presentation by the National Institutes of Health on the next generation of Covid vaccines that could provide broad protection against known and unknown strains of the virus, though officials noted a protective vaccine is likely a long way off. wide.

While the effectiveness of Pfizer-BioNTech and Moderna’s Covid vaccines against serious diseases appears to last for months or even years, their protection against infection wanes after only a few months.

“We need broader protection,” said Dr. Pamela McInnes, retired deputy director of the National Center for Advancing Translational Sciences at the National Institutes of Health. «We don’t want to be chasing this virus.»

During Thursday’s meeting, Dr. Peter Marks, the FDA’s top vaccine regulator, acknowledged that it may not be possible to simplify the Covid vaccine schedule to be exactly like the flu.

The FDA had proposed that the committee meet every June to select the strain or strains for the annual vaccine, giving manufacturers enough time to produce enough doses for a fall campaign.

Dr. Jerry Weir, director of the Division of Viral Products at the FDA’s Office of Vaccine Research and Review, said that even if the US took an annual approach, if a dangerous new variant emerged, the agency would likely he would still call an emergency meeting to discuss whether new reinforcements are needed.

Some committee members said they would prefer to make multiple annual meetings about Covid vaccines the norm.

Meeting once a year, they said, can give the public the impression that Covid is only a threat in the fall and winter months, like the flu, which is not the case.

«I think this pattern is not necessarily the flu,» said Dr. Henry Bernstein, a professor of pediatrics at the Hofstra University Zucker School of Medicine in New York. “We need to communicate that there is still value in getting vaccines outside of the typical flu window.”

They also questioned whether offering the boosters in the fall would mean people couldn’t get boosters at any other time of the year, meaning people had a limited amount of time to protect themselves.

While the committee was hesitant about advancing annual boosters, it was certain of the need to simplify vaccine formulation.

Currently, the bivalent vaccine, which targets the omicron BA.4 and BA.5 subvariants, in addition to the parent virus strain first identified in Wuhan, China in 2019, is only available as a booster vaccine. The primary vaccination series, which is given to anyone who is not vaccinated, still only targets the parent strain.

In a unanimous vote, the committee recommended using the bivalent formula in all future Covid vaccines, not just booster shots.

The FDA is not required to accept your committee’s recommendation, although it often does.

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