Pfizer/BioNTech’s Omicron-adapted booster approved by FDA for young children

Pfizer and BioNTech’s Omicron BA.4/BA.5-adapted bivalent COVID-19 vaccine has been authorised by the US Food and Drug Administration (FDA) for emergency use as a single booster dose for certain young children.

With this latest approval, children aged six months to four years who have completed their primary series with three doses of the companies’ original vaccine will be able to receive a 3µg booster dose of the bivalent vaccine after at least two months.

The vaccine is already authorised as the third dose of the three-dose primary series in this age group, but a booster dose is not authorised for these children at this time.

The partners have previously maintained that a fourth dose would ‘give families the option to further protect their young children against more recently circulating Omicron sublineages’.

The FDA’s expanded authorisation was supported by data showing a fourth dose of the bivalent booster elicited a higher Omicron BA.4/BA.5 neutralising response in children aged six months to four years, compared to those who received three doses of the companies’ original vaccine.

The safety and tolerability profile of the bivalent vaccine was similar to that of the original vaccine, the companies said.

Recent real-world evidence has also shown the bivalent vaccine to be protective against symptomatic COVID-19 disease in adults caused by XBB Omicron sublineages, which currently account for more than 85% of COVID-19 cases in the US.

Pfizer and BioNTech said that, in addition to their US application, they have made a submission to the European Medicines Agency (EMA) for use of the bivalent vaccine as both primary series and as a booster dose for children under five. The adapted vaccine is already authorised as a booster dose for those aged five years and older in the EU.

The announcement comes just days after Pfizer agreed to acquire oncology-focused biotech Seagen for a total enterprise value of $43bn, a deal fuelled by sales of the company’s COVID-19 products.

Under the terms of the agreement, which marks the biggest pharma deal since AbbVie agreed to acquire Allergan for $63bn in 2019, Pfizer will pay $229 in cash per Seagen share, a 32.7% premium to last Friday's closing price.