Bivalent COVID-19 booster elicits a stronger response than the original vaccine, Pfizer says

person holding injection

Pfizer and BioNTech said Friday that their bivalent covid-19 booster, which targets the original strain of sars-cov-2 and the omicron ba.4 and ba.5 sublineages, elicits stronger immune responses than their original vaccine.

Adults aged 18 to 55 years experienced a 9.5-fold increase in neutralizing antibody titers against the omicron sublineages compared with pre-booster levels. People older than 55 saw a 13.2-fold rise, according to data reported in a press release.

In adults aged older than 55 years, neutralizing antibodies were fourfold higher after receiving the bivalent booster compared with the original vaccine.

The FDA authorized the bivalent covid-19 booster for people aged 12 years or older on Aug. 31 and for children aged 5 to 11 years on Oct. 12.

Pfizer chairman and chief executive officer Albert Bourla, DVM, Ph.D., said in the press release that the updated data “provides confidence in the adaptability of our [messenger rna] platform and our ability to rapidly update the vaccine to match the most prevalent strains. ”

“These data demonstrate that our ba.4/ba.5-adapted bivalent vaccine works as conceptually planned in providing strong protection against the omicron ba.4 and ba.5 sublineages, ” Ugur Sahin, MD, CEO and co-founder of BioNTech, said in the release.

The results are from a phase 2/3 clinical trial of the bivalent booster that included 114 people who were tested 30 days after receiving either the bivalent booster or a booster dose of the original vaccine. Participants who received the bivalent vaccine had received a booster 10 to 11 months earlier, and those administered the original vaccine had received a booster about 7 months earlier.

Among the 38 participants aged 18 to 55 years, the geometric mean titer (GMT) against the omicron sublineages was 606 — a 9.5-fold rise over pre-booster levels. Among the 36 participants aged 55 years or older, the GMT was 896 — a 13.2-fold rise over their pre-booster levels.

Among 40 participants aged 55 years or older who received a booster of the original vaccine, the GMT was 236 — which is a 2.9-fold rise, meaning the neutralizing antibody titers were about fourfold higher for the bivalent booster over the original vaccine in this age group.

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Author: Stephen Feller

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