Bivalent COVID-19 booster outperforms original vaccine, Pfizer says
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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, and people older than 55 years 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 original vaccine.
The FDA authorized the bivalent 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, PhD, said in the press release that the updated data “provide 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.
BA.4 and BA.5 sublineages make up nearly two-thirds of the dominant variants circulating in the United States right now, with BA.5 representing just under half at 49.6% of circulating variants, according to the CDC.
Just 26.3 million people aged 5 years or older have received the updated bivalent booster, representing about 8.4% of the U.S. population, CDC data show. Roughly 266 million people in the United States — or 80.2% of the population — have completed a primary COVID-19 vaccine series.
“As we head into the holiday season, we hope these updated data will encourage people to seek out a COVID-19 bivalent booster as soon as they are eligible in order to maintain high levels of protection against the widely circulating omicron BA.4 and BA.5 sublineages,” Bourla said.
References:
- CDC. COVID Data Tracker: COVID-19 vaccinations in the United States. https://covid.cdc.gov/covid-data-tracker/#vaccinations_vacc-people-fully-percent-pop5. Accessed Nov. 4, 2022.
- CDC. COVID Data Tracker: Variant proportions. https://covid.cdc.gov/covid-data-tracker/#variant-proportions. Accessed Nov. 4, 2022.
- Pfizer and BioNTech announce updated clinical data for omicron BA.4/BA.5-adapted bivalent booster demonstrating substantially higher immune response in adults compared to the original COVID-19 vaccine. https://www.pfizer.com/news/press-release/press-release-detail/pfizer-and-biontech-announce-updated-clinical-data-omicron. Published Nov. 4, 2022. Accessed Nov. 4, 2022.
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