Early data show Pfizer’s omicron booster ‘substantially’ boosted antibodies against BA.5
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Early data from trials assessing the new Pfizer and BioNTech omicron-adapted booster vaccine show that the vaccine substantially increased protective antibodies against the BA.5 subvariant in adults.
“While we expect more mature immune response data from the clinical trial of our omicron BA.4/BA.5-adapted bivalent vaccine in the coming weeks, we are pleased to see encouraging responses just 1 week after vaccination in younger and older adults,” Pfizer chairman and CEO Albert Bourla, DVM, PhD, said in a press release. “These early data suggest that our bivalent vaccine is anticipated to provide better protection against currently circulating variants than the original vaccine and potentially help to curb future surges in cases this winter.”
According to the press release, the early data come from a phase 2/3 clinical trial that evaluated the safety, tolerability and immunogenicity of the omicron BA.4/BA.5-adapted vaccine. The trial assessed blood samples taken from 40 people aged 18 to 55 years and 40 people older than 55 years who received the omicron booster. Overall, the data showed a “substantial increase” in antibodies that block the BA.5 subvariant in both age groups based on sera taken 7 days after administration.
The companies also compared 40 people older than 55 who received the omicron booster with 40 people in the same age group who received a fourth dose of the original vaccine. According to the companies, the participants who received initial vaccine saw a limited increase in antibodies against BA.5. They added that the time between administration of the third dose and the omicron booster was approximately 11 months, whereas the time between the third dose and fourth dose of the original vaccine was 6 months.
The companies plan to release more data on the omicron-adapted vaccines at 1-month after administration in the coming weeks. They say these data will be used to support potential full licensure and global registration of the BA.4/BA.5-adapted vaccines.
The Pfizer and BioNTech omicron-adapted booster is authorized for everyone aged 5 years and older as of October 12.
The FDA authorized the omicron-adapted vaccines without direct human data on how they perform against omicron BA.5. During the vote to recommend the adapted vaccines, numerous Advisory Committee on Immunization Practices members voiced concerns over not having available human clinical data, although most members agreed the advantages of recommending the vaccines would outweigh risks.
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