An expert committee on Tuesday recommended that the Food and Drug Administration plan an updated booster shot of coronavirus vaccines that targets a form of the Omicron variant that has dominated for months.
The panel The vote clears the way for FDA regulators to push for a new vaccine formulation that the Biden administration hopes to come up with later this year, ahead of an expected winter resurgence of the virus.
The committee debated but did not specify which wording might work best. The FDA appeared to be strongly leaning towards a combination of the existing vaccine and two subvariants of Omicron, known as BA.4 and BA.5. According to new estimates from the Centers for Disease Control and Prevention, these two subvariants together now account for more than half of new cases in the country.
Dr. Peter Marks, who oversees the FDA’s vaccines division, said regulators need to recommend a specific formulation “very quickly” if new vaccines are to be rolled out in the fall. Makers of the mRNA vaccines, made by Moderna and Pfizer-BioNTech, need about three months to produce doses of a redesigned vaccine.
The results of clinical trials on a combination of the so-called “prototypes”, or existing vaccines, and Omicron itself have so far received mixed reviews. In briefing documents, regulators have suggested that such a design is “already somewhat outdated.”
The panel struggled with what one member called “trying to predict the future” of the direction the virus is taking. Another panelist called the data “uncomfortably sparse”. Some have said the most impressive booster may be the one offered by Novavax, a company whose vaccine isn’t even available in initial doses yet in the United States.
Dr. Adam C. Berger, a National Institutes of Health official, said that while he supported an updated recall in theory, “I’m not sure we have evidence to support a change necessarily today. “.
But despite much hesitation, 19 of the 21 panel members ultimately voted in favor of an updated recall. “We are all troubled by the steady erosion of immune protection,” said Dr. Mark Sawyer, infectious disease specialist at Rady Children’s Hospital in San Diego. “We’re going to be behind the eight ball if we wait any longer.”
The panel seemed generally against changing the formulation of the vaccine for people who have not yet been fully vaccinated.
“I don’t think we should lose the prototype. I think it’s a known entity and it’s doing very well in its current job,” said Dr. Amanda Cohn, a senior CDC official.
Little has been said of a variant other than Omicron, which has proven to be a global game changer, mitigating vaccine-induced protection and spawning even more cunning forms of the virus with the power to re-infect people. Dr Marks said figuring out how to counter the virus’ changes was “science at its hardest”.
Dr. Jerry Weir, an FDA official, said the Omicron forms have been dominant for about six months now and any virus form circulating in the fall is more likely to be related to the Omicron family than the versions. antecedents of the virus.
Overall, he said, the data indicate that a booster that incorporates an Omicron component produces a better antibody response against this family and offers “the potential for improved vaccine efficacy.”
Several committee members cautioned against waiting for more definitive data. CDC vaccine specialist Dr Melinda Wharton said she was confident a booster targeting some form of Omicron would increase the extent of immunity, as suggested by an adviser to the World Organization. of health.
Panel members largely bypassed the question of who should receive a further recall. Some have suggested that a fall booster will be badly needed, while others argue that because current vaccine protection has held up against serious illnesses, the next round of vaccines should be limited to the elderly and high. risk.
Although the overall death rate is low now compared to the start of the pandemic, CDC officials said Americans 70 and older have led to increased hospitalizations. Heather Scobie, an epidemiologist with the agency, said that despite “rather poor” uptake, second boosters reduced the risk of death in older people.
Federal health officials have suggested for months that more advanced vaccines may be needed to combat the rapidly evolving virus, warning that vaccine-induced protection against infection has waned, allowing some Americans to be reinfected even within several months.
In briefing documents, FDA officials said the risk of another major outbreak would increase later this year “due to the combination of waning immunity, new variant evolution, and increased inner activity”.
Moderna and Pfizer, the makers of the two most widely used vaccines in the United States, have both studied vaccines that target the first version of Omicron, expecting them to be seriously considered as the booster option. ‘fall. But the search was complicated by the sub-variants, for which neither company has yet developed plans. If the FDA chooses a vaccine that targets BA.4 or BA.5, it’s unclear whether either company will be able to study it and manufacture doses in time for a campaign. fall reminder.
Pfizer presented the only data on such a formulation – preliminary data from a mouse trial – suggesting it worked better against all subvariants of Omicron than the existing vaccine. But a company official said researchers don’t yet have a side-by-side comparison with a version targeting Omicron itself.
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