Pfizer and BioNTech’s Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine demonstrated a ‘substantial increase’ in antibody response above pre-booster levels after one week, according to early data from a phase 2/3 clinical trial in individuals ages 18 years and older.
A 30µg booster dose of the Omicron BA.4/BA.5-adapted bivalent vaccine has already been authorised for emergency use by the US Food and Drug Administration (FDA) for ages 12 years and older and granted marketing authorisation in the EU by the European Medicines Agency (EMA) for the same age group.
Most recently, a 10µg dose of BA.4/BA.5-adapted booster in children aged five to 11 years was granted emergency use authorisation EUA by the FDA.
The multi-centre, randomised, controlled phase 2/3 trial evaluating the safety, tolerability and immunogenicity of the booster showed similar responses across individuals aged 18 to 55 years and in those older than 55 years.
Moreover, when comparing responses in individuals older than 55 years who received either the bivalent vaccine, or the original vaccine, a 30µg booster dose of the original Pfizer/BioNTech COVID-19 vaccine elicited more limited increases in the neutralising antibody response against the Omicron BA.4/BA.5 variants.
This suggests that a booster dose of the bivalent vaccine provides better protection against the BA.4/BA.5 variants than the original vaccine for younger and older adults.
In terms of safety, the BA.4/BA.5-adapted booster was well tolerated, with early data indicating a favourable safety profile, similar to that of the original vaccine.
Commenting on the positive results, Albert Bourla, chairman and chief executive officer, Pfizer, said: “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.”
The bivalent vaccine contains mRNA encoding the original SARS-CoV-2 spike protein – present in the original Pfizer/BioNTech COVID-19 vaccine – together with mRNA encoding the spike protein of the Omicron BA.4/BA.5 subvariants.
“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,” said Professor Ugur Sahin, chief executive officer and co-founder of BioNTech.