On Oct. 13, 2022, Pfizer and BioNTech announced early data from a Phase 2/3 clinical trial (NCT05472038) evaluating 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-ﾵg 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 pre-booster levels based on sera taken 7 days after administration, with similar responses seen across individuals aged 18 to 55 years of age and those older than 55 years of age.