Pfizer injection
Pfizer injectionFlash 90

Pfizer and BioNTech said on Monday that the COVID-19 vaccine they developed together was 100 percent effective in protecting adolescents between the ages of 12 and 15.

In a statement quoted by The Hill, the two companies said the results from a long-term trial of 2,228 youth, measured from seven days through more than four months after the second dose, will form the basis for a planned supplemental application to the Food and Drug Administration (FDA) to expand approval of the vaccine for use in individuals in that age group.

The data were collected from November 2020 to September 2021, during the period when the delta variant began infecting large swaths of the US population.

The Pfizer vaccine is available for individuals ages 12 through 15 under emergency use, which was granted in May.

"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" Pfizer CEO Albert Bourla said in a statement quoted by The Hill.

Efficacy was consistently high across gender, race and ethnicity demographics, obesity and comorbidity status, the companies said.

Additionally, there were no serious safety concerns over a follow-up period of at least six months after the second dose of the vaccine.

There were 30 symptomatic infections in the trial, all in the placebo arm.

In addition to Pfizer, Moderna is also seeking FDA approval of its COVID-19 vaccine for adolescents.

Moderna said earlier this month it has been told that the US Food and Drug Administration will require additional time to complete its assessment of the company's COVID-19 vaccine for use in adolescents.

The FDA informed Moderna that the review may not be completed before January 2022, the company said in a statement.

The UK's health regulator approved Moderna's COVID-19 vaccine for use in children aged 12 to 17 years in August.