Pfizer says Israeli data shows that third shot restores 95% efficiency

A man receives his third dose of COVID19 vaccine at Sheba Medical Center on July 14, 2021 in Ramat Gan, Israel.

Amir Levy | Getty Images

A third dose of Pfizer‘s Covid vaccine six months after a second shot restores protection against infection to 95% in reality in Israel, according to data from the company to the Food and Drug Administration.

While the effectiveness of the mRNA vaccine declines over time, a booster shot was found to provide an immune response similar to the protection generated after a second dose, Pfizer said in a 52-page presentation from the agency on Wednesday.

Pfizer said data from Israel Covid vaccination programs that administer boosters to the entire population show that a third shot “has a reactogenicity profile similar to that seen after receiving the second primary series dose and restores high levels of protection against Covid-19 failure (back to approximately 95% protection).” Data were collected from 1 July to 30 August when the delta variant rose throughout the country.

The FDA released the information when the agency is under pressure from the Biden administration to approve booster shots for the general population as early as next week. But agency staff refused to take a position on the need for a third shot, citing the lack of verified data in a 23-page report released later Wednesday.

Staff said they were reviewing other “potentially relevant” studies on declining immunity from Pfizer’s vaccine, but the studies have yielded mixed results and some of these data may be more reliable than others. The Israeli data came from an observational study, which does not follow the same standards for a formal clinical trial.

“It should be recognized that while observational studies may allow for an understanding of true effectiveness, there are known and unknown prejudices that may affect their reliability. Because of these prejudices, some studies may be more reliable than others,” the FDA staff wrote in their analysis.

Pfizer’s report is intended to inform the FDA’s Advisory Committee on Vaccines and Related Biological Products, which meets on Friday to review requests from Pfizer and its coronavirus vaccine partners. BioNTech, to approve covid booster doses for the general public. The published documents provide a glimpse of the FDA’s view of third shots.

Based on the data, Pfizer said it “requests licensing of a booster dose of [the Pfizer vaccine] administered intramuscularly approximately 6 months after dose 2 to persons over 16 years of age. “

The company also included data from a phase 3 study involving approximately 300 people aged 19 to 55 years. One third of the participants were overweight and one third were overweight, according to the documents.

Pfizer and BioNTech are looking for the agency’s OK to distribute booster doses to people 16 and older in the United States


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