Pfizer and BioNTech unveiled top-line results from a Phase 2/3 trial, in which their Covid-19 vaccine Comirnaty elicited superior immune responses in children aged five to 11 years, with a favourable safety profile.

The study used a two-dose regimen of 10µg administered 21 days apart, a smaller dose compared to the 30µg used for individuals aged 12 years and above.

Antibody responses in the study participants, who received 10µg doses were comparable to those in people aged 16 to 25 years, immunised with 30µg doses.

Pfizer and BioNTech said that the 10µg dose was selected as the preferred dose, considering safety, tolerability and immunogenicity in children five to 11 years of age.

Pfizer chairman and CEO Albert Bourla said: “Over the past nine months, hundreds of millions of people ages 12 and older from around the world have received our Covid-19 vaccine.

“We are eager to extend the protection afforded by the vaccine to this younger population, subject to regulatory authorization, especially as we track the spread of the Delta variant and the substantial threat it poses to children.

“Since July, paediatric cases of Covid-19 have risen by about 240 per cent in the US – underscoring the public health need for vaccination.

“These trial results provide a strong foundation for seeking authorization of our vaccine for children five to 11 years old, and we plan to submit them to the FDA and other regulators with urgency.”

The Phase 1/2/3 trial was designed to evaluate the safety, tolerability, and immunogenicity of their Covid-19 vaccine in 4,500 children, aged below 12 years.

In the trial, Comirnaty showed a neutralising antibody geometric mean titre (GMT) of 1,197.6 in children aged five to 11 years, with a high immune response one month after the second dose.

The vaccine was well tolerated in the age group, with side effects generally comparable to those observed in participants aged 16 to 25 years.

Pfizer and BioNTech intend to submit the data to the US Food and Drug Administration (FDA), European Medicines Agency (EMA) and other regulators.

BioNTech CEO and co-founder Ugur Sahin said: “We are pleased to be able to submit data to regulatory authorities for this group of school-aged children before the start of the winter season.

“The safety profile and immunogenicity data in children aged 5 to 11 years vaccinated at a lower dose are consistent with those we have observed with our vaccine in other older populations at a higher dose.”