Trial results show 100% efficacy of Pfizer-BioNTech Covid-19 vaccine in people ages 12 to 15

Of the 2,228 people taking part in the trial, only 30 were confirmed to have contracted symptomatic cases of Covid-19 and all were among the group who had been administered a placebo, instead of the actual vaccine.

"As the global health community works to increase the number of vaccinated people around the world, these additional data provide further confidence in our vaccine's safety and effectiveness profile in adolescents," said Albert Bourla, chairman and chief executive officer, Pfizer.

"This is especially important as we see rates of COVID-19 climbing in this age group in some regions, while vaccine uptake has slowed."

The trial results demonstrated the vaccine's efficacy seven days through over four months after the second dose.

However, the safety profile was assessed through at least six months of follow-up after the second dose had been given.

BioNTech said the data would support admission for full regulatory approval of the vaccine for use in people ages 12 to 15.