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In a one-day virtual meeting, a panel of experts advising the Food and Drug Administration spoke out in support of efforts to develop new variant-appropriate COVID-19 vaccines.
The committee was not asked to vote on agency-specific recommendations, but rather discussed the decision-making framework when to change the viral strain(s) used for future vaccines, including boosters.
“I think we are in uncharted territory because with SARS-CoV-2 a lot of things have happened that have never happened before,” said Dr. Arnold Monto, professor emeritus at the University of Michigan and chairman. acting committee.
It is likely that the group will meet again in May or June to consider a more specific proposal for the reformulation of COVID-19 vaccines.
The process used to adjust annual flu vaccines to match circulating strains is a model that can shed light on the process for COVID-19, but there are still many unknowns about how the coronavirus may change and stark differences between the influenza virus and SARS-CoV-2.
Fall target for a new booster type
The critical consideration is whether a variant-specific booster should be available this fall. The rise of the omicron variant, and lately of a sub-variant called BA.2, has sharpened the issue. The vaccines currently used in the United States are based on the form of the virus that circulated early in the pandemic and are less effective against some later strains.
“Although we have seen a significant drop in the number of COVID-19 cases in the country, the virus is still circulating and it will continue to do so and potentially cause waves of increased number of cases,” said Dr. To fart. Marks, director of the FDA’s Center for Biologics Evaluation and Research, at the start of the meeting. “This is of particular concern as we head into the fall and winter season.”
Marks also noted that the coronavirus will have had even more time to evolve by the time fall arrives in the United States.
During the morning session, Israeli researchers presented data on declining protection a single booster dose of the Pfizer-BioNTech vaccine and the increased protection of a second booster against infections, which were transient, and serious illnesses, which lasted longer. The rapid spread of the omicron variant contributed to the decline in protection from immunization with a boost.
Israeli authorities approved a second booster in early January for people 60 and older and others at high risk or who worked in the healthcare sector. The Israeli experience has contributed to the The FDA decision at the end of March to authorize a second booster dose for persons aged 50 and over as well as for other immunocompromised persons.
Predicting viral evolution is “quite difficult”
Rapid genetic changes in the coronavirus determine its ability to evade the immune response from vaccination and previous infections. Ongoing changes complicate decisions about which strains to include in new vaccines.
“Generally, from everything we’ve seen, we should expect a lot of evolution in the future, and we should have methods to track that evolution in terms of our vaccine platforms,” Trevor said. Bedford, who studies viral evolution at the Fred Hutchinson Cancer Center in Seattle.
He said it was “quite difficult” to predict where the virus is heading. The coronavirus has evolved faster than the flu. Significant new variants of the coronavirus have emerged in just months instead of the years it takes the flu to make such leaps.
Based on the rate of evolution of the coronavirus so far and the uncertainty about what lies ahead, Bedford estimates that a dangerous new variant like omicron could emerge within about a year and a half or so. -not be for more than a decade.
There’s not a lot of time to make changes to vaccines in time for a vaccination campaign this fall. “If you’re not on your way to a clinical trial in early May, I think it’s going to be very difficult to get enough product from the manufacturers to meet the demand,” said Robert Johnson, deputy undersecretary of the Federal Biomedical Advanced Research and Development Authority.
The FDA brands have acknowledged that there is a compressed timeline to decide on recall makeup, but there may be “some wiggle room” that could allow for a decision in May or June.
There is a lot to be done on the decision. “We just can’t boost people as often as we are,” Marks said, adding that the second booster dose recently authorized by the FDA was “an interim measure” to help protect those most vulnerable.
The goal of a reworded recall later this year, Marks said, would be to “strengthen again to protect against a surge that may come when we are most at risk.”
In his closing remarks, committee chair Monto said, “We would like to see an annual flu-like vaccination, but we realize that the evolution of the virus will dictate how we respond.”
Rob Stein contributed to this report.