A booster dose of the Pfizer-BioNTech Covid-19 vaccine appears to provide strong protection against the omicron variant, the companies announced Wednesday.
They said lab study results show a third dose of their vaccine provides a similar level of neutralizing antibodies to omicron, comparable to two doses against the original coronavirus and other variants that have emerged.
Blood samples from those who received only the primary series of the vaccine, on average, did see a 25-fold drop in antibodies against the new variant. That may indicate that two doses of the vaccine may not be sufficient to protect against infection with omicron, although they may still prevent severe disease, the companies said.
"If these data hold then these are good signs," said Ali Ellebedy, an associate professor of pathology and immunology at Washington University School of Medicine in St. Louis. "It means that on the very least fully vaccinated individuals ... will likely be protected from severe disease."
As the highly mutated omicron variant, first identified in South Africa, spreads around the globe, scientists are racing to determine how the available vaccines will work against it.
"Three doses against omicron are almost equivalent to the two doses effectiveness we had against the ... original variant," Pfizer CEO Albert Bourla said Wednesday on NBC's "TODAY" show.
"You may need to go get the third booster faster, and that’s something that the health authorities should consider very carefully and make their recommendations," he added. "But clearly having two doses compared to nothing protects you way better than having nothing."
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Currently, the Centers for Disease Control and Prevention urges all adults ages 18 and older to get a booster shot 6 months after their initial Pfizer or Moderna series or two months after the single-dose Johnson & Johnson vaccine shot.
The vaccine companies said the results are preliminary. The findings were detailed in a news release, and the full data has not yet been made available for other scientists to scrutinize.
But lab studies are only one piece of the puzzle. Other data is also needed to determine whether a new vaccine is needed. Scientists need to understand how transmissible the omicron variant is as well as how sick it makes people (early data suggests it’s more contagious than the delta variant, but causes milder illness).
The results from Pfizer-BioNTech are the first announced by vaccine makers.
According to the news release, blood samples were tested from people who had received either two or three doses of the vaccine. The samples were collected three weeks after the second dose or one month after the booster.
Tuesday, a South Africa research institute also released lab results on how the Pfizer vaccine fared against omicron, showing about a fortyfold reduction in vaccine-induced antibodies that could neutralize the new variant. That study didn't look at booster shots, however.
On Nov. 25, the vaccine companies started to develop an omicron-specific vaccine. First batches of the vaccine can be produced and ready for delivery in about 100 days, depending on authorization from federal regulators, Pfizer has said.
"If we need a new vaccine, those tests are telling me we will be able to have a very good one if we need one against omicron, because really we’re able with some tweaks to produce way higher results," Bourla said.
"The current booster will maintain protection, but if we need one, we will make one and we will have it by March," he said.
Moderna and Johnson & Johnson are expected to release lab results from the omicron variant in the coming days. Academic research institutions are also looking into how well the vaccine works against omicron.
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Elisha Fieldstadt contributed.
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