AILSA CHANG, HOST:
Today, Pfizer released preliminary data showing that a third dose of its COVID-19 vaccine does boost a person's immunity, at least as far as can be measured in the lab. As NPR's Joe Palca reports, this news comes as evidence begins to show that the efficacy of the vaccine may be waning over time.
JOE PALCA, BYLINE: The preliminary data come from a small group of subjects who had already received two doses of the Pfizer-BioNTech vaccine. Mikael Dolsten is Pfizer's chief scientific officer. He gave the news in a conference call with investors.
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MIKAEL DOLSTEN: We observed a significant boost in neutralizing antibodies following a third dose of the current vaccine for both wild type and the beta variant.
PALCA: The wild type is the strain of the virus that originated in China. The beta variant first showed up in South Africa and has been of particular concern because it's the variant the vaccines are least effective against. Dolsten also said another laboratory study shows that a third shot boosted immunity to the delta variant.
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DOLSTEN: These preliminary data are very encouraging as delta continues to spread.
PALCA: These results come from using a boost with the original Pfizer-BioNTech vaccine. The company said it will also start testing a modified vaccine specifically targeting the delta variant. The unanswered question is when or whether to give a booster. Both laboratory studies and data from vaccinated people show the vaccine's efficacy appears to be waning over time. But federal health officials say the current vaccines still work well enough, although they have begun to say certain populations, such as those with weakened immune systems, may need a third dose of the vaccine. Pfizer CEO Albert Bourla said on the investor call that Pfizer believes the need is broader than that.
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ALBERT BOURLA: What we have said is not - you know, I - for months, I'm saying that we believe, based on the data that we received or at least the early data, we will need a booster 8 to 12 months and - from the second dose. But we haven't submitted data yet.
PALCA: If it's still an open question about how good a vaccine will be for people, it's bound to be good for Pfizer's bottom line. Bourla told investors the company had second-quarter revenue of nearly $8 billion from the vaccine.
Joe Palca, NPR News. Transcript provided by NPR, Copyright NPR.
