Pfizer and BioNTech have submitted an application seeking Emergency Use Authorization (EUA) from the US Food and Drug Administration (FDA) for a 10µg booster of their Omicron BA.4/BA.5-adapted bivalent Covid-19 vaccine in children.

The companies sought authorisation for booster vaccine usage in children aged five to 11 years.

Their application is based on bivalent Omicron BA.1-adapted vaccine’s safety and immunogenicity findings, non-clinical and manufacturing data of 10µg bivalent Omicron BA.4/BA.5-adapted vaccine, as well as Omicron BA.4/BA.5-adapted vaccine’s pre-clinical findings.

A Phase I/II/III clinical trial of the Omicron BA.4/BA.5-adapted bivalent Covid-19 vaccine was initiated recently in children aged six months to 11 years.

The paediatric trial will assess the safety, tolerability and immunogenicity of varying vaccine doses and dosing schedules.

It will have four substudies. Substudy A will enrol subjects aged six to 23 months who are naïve to the Covid-19 vaccine. 

Substudy B and C will have subjects aged six months to four years who have received two-three and three doses of original vaccine doses, respectively.

Substudy D will enrol subjects aged five to 11 who have received two-three doses of the original vaccine.

This trial comes after a prior Phase I/II/III study, where the original Covid-19 vaccine was demonstrated to be well-tolerated.

Additionally, this vaccine was found to offer greater protection levels against the SARS-CoV-2 virus when its Omicron BA.2 strain was dominant.

The companies also intend to seek marketing authorisation from the European Medicines Agency for the Omicron BA.4/BA.5-adapted bivalent vaccine for use in children of this age group soon.

Earlier this month, the US FDA granted EUA for Pfizer -BioNTech’s bivalent Covid-19 vaccine booster.