Pfizer and BioNTech announced positive findings from a study evaluating 2 Omicron-adapted COVID-19 vaccine candidates.

The phase 2/3 trial assessed the safety, tolerability, and immunogenicity of a booster (fourth) dose of an Omicron-adapted monovalent vaccine candidate and a bivalent vaccine candidate (combination of the Pfizer-BioNTech COVID-19 Vaccine and a vaccine candidate targeting the spike protein of the Omicron BA.1 variant of concern). The trial included 1234 adults 56 years of age and older; 2 dose levels (30µg and 60µg) were investigated.

Findings showed that 1 month after administration, the monovalent 30µg and 60µg vaccine candidates increased neutralizing geometric mean titers (GMT) against Omicron BA.1 by 13.5- and 19.6-fold, respectively, above prebooster dose levels, while the bivalent vaccine candidates (30µg and 60µg) increased neutralizing GMT by 9.1- and 10.9-fold. Neutralizing GMTs against Omicron BA.4 and BA.5 were also observed though to a lesser extent than against BA.1 (3-fold lower).

When compared with the current Pfizer-BioNTech COVID-19 Vaccine, the Omicron-adapted vaccine candidates elicited higher neutralizing antibody responses against Omicorn BA.1. Findings showed geometric mean ratios for Omicron neutralizing antibody response consistent with the regulatory requirement of superiority. Both vaccine candidates also demonstrated a favorable safety and tolerability profile.

“Based on these data, we believe we have 2 very strong Omicron-adapted candidates that elicit a substantially higher immune response against Omicron than we’ve seen to date,” said Albert Bourla, Chairman and CEO, Pfizer. “We look forward to discussing these data with the scientific community and health authorities so we may rapidly introduce an Omicron-adapted booster as soon as possible if authorized by regulators.”


Pfizer and BioNTech announce Omicron-adapted COVID-19 vaccine candidates demonstrate high immune response against Omicron. News release. Pfizer Inc. and BioNTech SE. June 25, 2022. Accessed June 27, 2022.