New York, Mar 31 (IANS): Pharmaceutical companies Pfizer and BioNTech on Wednesday announced that their Covid-19 vaccine -- BNT162b2 -- demonstrated 100 per cent efficacy and robust antibody responses in a Phase 3 trial in adolescents between 12 to 15 years old.

The Phase 3 clinical trial enrolled 2,260 adolescents aged between 12 to 15 years old in the US.

"We share the urgency to expand the authorisation of our vaccine to use in younger populations and are encouraged by the clinical trial data from adolescents between the ages of 12 and 15," Albert Bourla, Chairman and Chief Executive Officer, Pfizer, said in a statement.

In the trial, 18 cases of Covid-19 were observed in the placebo group (n=1,129) versus none in the vaccinated group (n=1,131).

Vaccination with BNT162b2 elicited SARS-CoV-2-neutralising antibody geometric mean titres (GMTs) of 1,239.5, demonstrating strong immunogenicity in a subset of adolescents one month after the second dose.

This compared well (was non-inferior) to GMTs elicited by participants aged 16 to 25 years old (705.1 GMTs) in an earlier analysis. Further, BNT162b2 administration was well tolerated, with side effects generally consistent with those observed in participants 16 to 25 years of age.

The BNT162b2 has not been approved or licensed by the US Food and Drug Administration (FDA), but has been authorised for emergency use by FDA under an Emergency Use Authorization (EUA) to prevent Covid-19 for use in individuals 16 years of age and older.

"We plan to submit these data to FDA as a proposed amendment to our Emergency Use Authorisation in the coming weeks and to other regulators around the world, with the hope of starting to vaccinate this age group before the start of the next school year," Bourla added.