Pfizer, BioNTech seek US okay for Omicron BA.4/BA.5 booster

Pfizer and BioNTech have asked the FDA for emergency authorisation of an Omicron-targeted COVID-19 booster vaccine ahead of the planned autumn immunisation campaign in the US.

The new version of their Comirnaty vaccine includes mRNA for the spike protein of the wild-type SARS-CoV-2 that first emerged in late 2019, as well as for the BA.4 and BA.5 subvariants of the now-dominant Omicron variant. It will also be filed in the EU within the next few days, said Pfizer.

"Having rapidly scaled up production, we are positioned to immediately begin distribution of the bivalent Omicron BA.4/BA.5 boosters, if authorised, to help protect individuals and families as we prepare for potential fall and winter surges," said Pfizer chief executive Albert Bourla.

The company already has a $3.2 billion order from the federal government in place for 105 million doses of a booster vaccine.

The application is based on clinical data from the two companies' version of the booster jab based on Omicron's BA.1 subvariant, and preclinical and manufacturing data on the BA.4/BA.5 vaccine.

Experts at an FDA advisory committee meeting in June recommended the use of updated Omicron-directed vaccines for the upcoming booster campaign, and said they would prefer the autumn boosters to target BA.4 and BA.5 directly, as these now account for substantially all COVID-19 cases in the US.

However, the rapid emergence of the latest variants has meant there is not enough time to carry out clinical assessments before dosing is due to start next month.

According to Pfizer/BioNTech, preclinical data has shown that a booster dose with the BA.4/BA.5-adapted bivalent vaccine generated a strong neutralising antibody response against Omicron BA.1, BA.2 and BA.4/BA.5 variants, as well as the original wild-type strain.

Pfizer and Moderna have both filed a bivalent COVID-19 vaccine based on wild-type SARS-CoV-2, as well as the BA.1 subvariant in Europe, and earlier this month, Moderna secured the first approval for its bivalent shot in the UK.

Pfizer said the EMA and International Coalition of Medicines Regulatory Authorities (ICMRA) had given guidance to file for approval of a BA.1-based vaccine.

COVID-19 cases in the US are have averaged around 93,000 a day over the seven days to 22 August, but are expected to rise sharply as the colder weather approaches.