The expanded EUA is based on data, showing booster dose of Pfizer-BioNTech Covid-19 Vaccine induced superior immune response in kids aged five to 11 years with a favourable safety profile

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A vial of the Pfizer–BioNTech vaccine. (Credit: US Secretary of Defence/Wikipedia)

The US Food and Drug Administration (FDA) has expanded the emergency use authorisation (EUA) for a booster dose of Pfizer and BioNTech’s Covid-19 vaccine, to include children aged five to 11 years.

The third dose of their vaccine was previously granted FDA EUA for use in individuals aged 12 years and above, after completion of the primary series vaccination.

With the current expanded EUA, the children aged below 12 years are allowed to receive the third dose of Pfizer-BioNTech Covid-19 vaccine, marketed as Comirnaty, at least five months after the primary series.

Pfizer has selected the same 10µg dose strength, as in the primary two-dose primary series, for the booster shot in this age group.

The expanded EUA is supported by the data from the Phase 2/3 study, which showed that a booster dose of the Pfizer-BioNTech Covid-19 vaccine induced a strong immune response.

In the study, the third dose of Comirnaty has generated neutralising antibodies against both the Omicron variant and wild-type SARS-CoV-2 virus, regardless of prior infection.

Pfizer said that the booster dose was well tolerated in kids aged five to 11 years, with a safety profile similar to the primary series, and no new safety signals observed.

The Phase 2/3 data builds on efficacy data for the primary two-dose series which showed 90.7% efficacy in children aged five to 11 years, without prior infection.

Pfizer and BioNTech have filed an application with the European Medicines Agency (EMA) seeking approval for Comirnaty booster dose in this age group, with plans to seek approval from other regulatory agencies worldwide.

Furthermore, the companies are studying the safety, tolerability, and immunogenicity of a 3µg formulation of their Covid-19 vaccine in children aged six months to four years, in an ongoing Phase 1/2/3 clinical trial.

The Phase 1/2/3 trial is designed to initially enrol up to 4,500 children in the US, Finland, Poland, and Spain, at more than 90 clinical trial sites.