The Pfizer-BioNTech COVID-19 vaccine was 100% effective in teens ages 12 to 15, the company said Wednesday, providing hope there will be an option for people under age 16 before the next school year.

Pfizer said it found 18 cases within a placebo group but none in the vaccine arm of a trial involving over 2,200 participants. The antibody response also exceeded levels detected in an earlier trial of people ages 16 to 25.

The company said it will amend its emergency-use filing with the Food and Drug Administration in the coming weeks, as they target a rollout before fall.

New clinical trials showed that Pfizer's COVID-19 vaccine elicits "100% efficacy and robust antibody responses" in adolescents from 12-15 years old, the drug company announced Wednesday. The trial included 2,260 trial participants; the results are even better than earlier responses from participants ages 16-25.

Pfizer and its vaccine partner BioNTech say they will submit the results "as soon as possible" to the U.S. Food and Drug Administration and the European Medicines Agency, asking regulators to expand their authorizations for the vaccine's use in young people.

Pfizer says its Covid-19 vaccine is safe and 100 percent effective in preventing the illness in teenagers ages 12 to 15.

"This is exactly the news that we hoped to hear," said Dr. Buddy Creech, a pediatric infectious disease expert at the Vanderbilt University Medical Center in Nashville, Tennessee. Creech was not involved in the Pfizer research.

The vaccine, given in two doses three weeks apart, is already cleared for emergency use in people ages 16 and up.