Pfizer-BioNTech Releases Early Results from Bivalent Booster Vaccine Trial

This morning, Pfizer Inc. and BioNTech SE released early data from a phase 2/3 trial evaluating the safety and immunogenicity of their Omicron BA.4/BA.5 bivalent COVID-19 vaccine.

“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,” said Albert Bourla, the chairman and CEO of Pfizer. “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.”

Preliminary results suggest one 30-µg dose of the Omicron BA.4/BA.5 bivalent vaccine significantly raised antibody titers above pre-booster levels. Notably, these results were comparable across participants 18-55 years old and participants older than 55 years.

“Together, these data suggest a 30-µg booster dose of the Omicron BA.4/BA.5-adapted bivalent vaccine is anticipated to provide better protection against the Omicron BA.4/BA.5 variants than the original vaccine for younger and older adults,” Pfizer said in a statement.

The multicenter, randomized, controlled phase 2/3 study (NCT05472038) included 900 healthy volunteers 12 years and older in the US. The participants had received at least 3 doses of an authorized COVID-19 vaccine at the time of enrollment.

During the trial, the participants 18 years and older received a booster dose of either 30-µg or 60-µg of Pfizer-BioNTech’s Omicron BA.4/BA.5-adapted COVID-19 vaccine. The participants 12-17 years of age received a 30-µg vaccine dose.

Sera collected 7 days after bivalent booster administration showed a substantial increase in Omicron BA.4/BA.5 neutralizing antibody response. With these data, investigators believe this updated bivalent booster will offer younger and older adults better protection against the Omicron BA.4/BA.5 sublineages than the original COVID-19 vaccine.

A 30-µg booster dose of Pfizer-BioNTech’s Omicron BA.4/BA.5 bivalent vaccine was issued emergency use authorization (EUA) for persons 12 years and older by the US Food and Drug Administration (FDA)

“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,” Bourla said.