Global pharma major Pfizer and BioNTech SE on Monday said trial results of COVID-19 vaccine showed that it is safe and produced robust neutralizing antibody response in children aged five to 11 years, and they plan to seek regulatory approvals as soon as possible.

Children aged five to 11 years were given a two-dose regimen of 10 microgrammes (g) administered 21 days apart, a smaller dose than the 30 g dose used for people 12 years and older, the companies said in a joint statement.

"In participants 5 to 11 years of age, the vaccine was safe, well tolerated and showed robust neutralizing antibody responses," the statement said.

The companies plan to submit these data to the US Food and Drug Administration (FDA), European Medicines Agency (EMA) and other regulators as soon as possible, the statement said.

"Since July, paediatric cases of COVID-19 have risen by about 240 percent 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 5 to 11 years old, and we plan to submit them to the FDA and other regulators with urgency," Pfizer Chairman and Chief Executive Officer Albert Bourla said.

For the United States, the companies expect to include the data in a near-term submission for Emergency Use Authorization (EUA) as they continue to accumulate the safety and efficacy data required to file for full FDA approval in this age group, the companies said.

A request to the EMA to update the EU Conditional Marketing Authorization is also planned, they added.

"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," BioNTech CEO and co-founder Ugur Sahin said.

Topline readouts for the other two age cohorts from the trial children 2-5 years of age and children 6 months to 2 years of age are expected as soon as the fourth quarter of this year, the statement said.

The Phase 1/2/3 trial initially enrolled up to 4,500 children ages 6 months to 11 years of age in the United States, Finland, Poland, and Spain from more than 90 clinical trial sites, it added.

"It was designed to evaluate the safety, tolerability, and immunogenicity of the Pfizer-BioNTech vaccine on a two-dose schedule (approximately 21 days apart) in three age groups: ages 5 to 11 years; ages 2 to 5 years; and ages 6 months to 2 years," the statement said.

Based on the Phase 1 dose-escalation portion of the trial, children aged 5 to 11 years received two-dose schedule of 10 g each while children under age 5 received a lower 3 g dose for each injection in the Phase 2/3 study. The trial enrolled children with or without prior evidence of SARS-CoV-2 infection, it added.