Pfizer and BioNTech offered an updated look at the efficacy of their COVID-19 vaccine, BNT162b2. The overall efficacy figure remained high at 91.3%, and the shot showed it can protect against a notoriously hard-to-tackle variant first identified in South Africa.
The pair’s mRNA vaccine is 91.3% effective against symptomatic COVID-19 disease as measured in people who have been immunized with the second dose of the shot for up to six months, the companies said Thursday.
The new efficacy data, plus a safety analysis comprising data from more than 12,000 people who were fully immunized for at least six months, allow the companies to file a drug application with the FDA to turn the shot’s emergency use authorization into a full approval, Pfizer CEO Albert Bourla, Ph.D., said in a statement.
The efficacy level is slightly down from the 95% number the vaccine first posted in the trial. With those data, Pfizer secured an FDA emergency use authorization in December. Since that initial analysis, more COVID-19 cases have accrued, increasing to 927 as of March 13 from the previous 170.
Of the total cases, investigators recorded 850 in the placebo group compared with 77 in the vaccine cohort. Thirty-two severe COVID-19 cases were recorded, all in the placebo group, translating into a 100% efficacy against severe disease for the vaccine.
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The emergence of new variants of the novel coronavirus, especially one dubbed B.1.351 that was first identified in South Africa, raised concerns over the efficacy of existing vaccines. Previous studies in labs found significantly reduced neutralizing ability of the Pfizer-BioNTech shot against the B.1.351 variant as compared with an earlier virus isolate, though BioNTech CEO Ugur Sahin has said the level is still enough to offer protection.
In the newly released data, the South Africa branch of the trial showed the vaccine to be 100% efficacious in the B.1.351-dominant region. Among the 800 participants enrolled there, nine cases of COVID-19 were observed, all in the placebo group. Six of the nine were confirmed to be caused by B.1.351.
“These data also provide the first clinical results that a vaccine can effectively protect against currently circulating variants, a critical factor to reach herd immunity and end this pandemic for the global population,” Sahin said in a statement Thursday.
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Demand for the Pfizer-BioNTech shot, also known as Comirnaty, has soared thanks to the strong efficacy it has demonstrated thus far. Pfizer expects $15 billion in 2021 sales from existing orders of the vaccine. The companies have so far inked supply deals for 1.4 billion doses.
The companies are working around the clock to try to meet demand. This week, BioNTech said the partners aim to churn out 2.5 billion doses this year.
Meanwhile, Pfizer and BioNTech have recently launched a new study to evaluate the effect of a third, booster shot against circulating and potential new variants. They said it would offer a “flexible solution for rapidly adapting the vaccine” for use against potential new virus strains.
BioNTech management also suggest a potential for a booster every six to 18 months based on observations of declining neutralizing antibody titers after the initial two-dose vaccination schedule. But in an investor note Tuesday, SVB Leerink analyst Daina Graybosch argued the third shot “could be more broadly effective and durable in protection than the initial prime/boost of BNT-162b2—limiting the need for long-term re-boosting.”