Pfizer and BioNTech announced early data from a phase II/III clinical trial assessing the safety, tolerability, and immunogenicity of the companies' Omicron BA.4/BA.5–adapted bivalent COVID-19 vaccine (Pfizer-BioNTech COVID-19 Vaccine, Bivalent [original and Omicron BA.4/BA.5]).
A 30-mcg booster dose of the Omicron BA.4/BA.5–adapted bivalent vaccine demonstrated a substantial increase in the Omicron BA.4/BA.5 neutralizing antibody response above prebooster levels based on sera taken 7 days after administration, with comparable responses observed across individuals aged 18 to 55 years and those aged older than 55 years (40 participants in each age group).
When comparing responses in individuals aged older than 55 years who received either the bivalent vaccine, or the original vaccine, a 30-mcg booster dose of the original Pfizer-BioNTech COVID-19 Vaccine (also referred to as BNT162b2 Wild-Type) provoked more limited increases in the neutralizing antibody response against the Omicron BA.4/BA.5 variants.
COVID-19 vaccine responses to date have reliably shown consistent trends across age groups and are further supported by these early data on the bivalent vaccine. Collectively, these data suggested a 30-mcg booster dose of the Omicron BA.4/BA.5Ðadapted bivalent vaccine is anticipated to provide better protection against the Omicron BA.4 and BA.5 variants than the original vaccine for younger and older adults. The Omicron BA.4 and BA.5–adapted bivalent vaccine was well tolerated, with early data indicating a favorable safety profile comparable to that of the original vaccine.
Albert Bourla, chairman and CEO of Pfizer, stated, "Since the earliest days of the pandemic, we have strived to transparently share data regarding our COVID-19 vaccines in the interest of public health. 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 one week after vaccination in younger and older adults. 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."
"These preliminary findings are consistent with our preclinical data showing a substantial increase in the neutralizing antibody response against the Omicron sublineages BA.4 and BA.5," stated Ugur Sahin, MD, CEO and cofounder of BioNTech. "The current dominance of BA.4/BA.5 and related sublineages, underscores the importance of our data and science-based approach to develop a vaccine which is adapted to these prevalent strains of the virus and make it available in a timely manner."
Immunogenicity was assessed using a SARS-CoV-2 live virus fluorescent focus reduction neutralization test assay. Sera were collected 7 days post second booster dose from participants aged older than 55 years (40 participants in each age group) and compared with 7-day post sera from 40 participants aged older than 55 years who had received three prior doses of BNT162b2 encoding the wild-type spike protein of SARS-CoV-2 and a second booster with BNT162b2 Wild-Type.
Sera were also collected at 7 days post second booster dose from participants aged 18 to 55 years who received the Omicron BA.4/BA.5–adapted bivalent booster (n = 40) to compare bivalent vaccine responses in younger and older adults. The time between third and fourth doses for the bivalent vaccine recipients was nearly 11 months compared with approximately 6 months for the original vaccine. Despite this difference, baseline neutralizing antibody titers were generally analogous across groups. Among the participants, samples were equally stratified at baseline in each group between those who had a prior or current history of SARS-CoV-2 and those with no prior or current history of SARS-CoV-2.
Additional data measuring responses at 1 month post administration of the Omicron BA.4/BA.5 bivalent vaccine booster are anticipated in the coming weeks. These data will be utilized to support potential full licensure and global registration of the companies' Omicron BA.4/BA.5–adapted bivalent COVID-19 vaccine. Additionally, the companies have initiated a parallel phase I/II/III trial examining the Omicron BA.4/BA.5Ðadapted bivalent vaccine among children aged 6 months through 11 years.
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Published October 24, 2022