Pfizer Inc. said its Covid-19 vaccine was 100% effective in a final-stage trial in kids ages 12 to 15, a finding that could pave the way for teens and pre-teens to get shots before the next school year.

The vaccine is already authorized in the U.S. for people ages 16 and up. Pfizer and its partner BioNTech SE said they planned to submit the data to regulators in the U.S and Europe as soon as possible, seeking to amend their vaccine authorizations to include the younger age group.

In the study of 2,260 adolescents, the vaccine produced antibodies against the Covid-19 that exceeded the level seen in vaccinated young adults, Pfizer and BioNTech said in a statement. All 18 cases of Covid-19 in the study were in adolescents who were administered a placebo, the companies said. Side effects were consistent with those experienced by people ages 16 to 25.

A Pfizer spokesperson, meanwhile, said the company is in conversations with the U.S. Food and Drug Administration on what the next steps may be. The FDA declined to comment on how quickly it might act on the data.

“We share the urgency to expand the authorization 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,” Pfizer Chief Executive Officer Albert Bourla said in the statement.

Pfizer’s shares rose 0.2% at 10:17 a.m. in New York while BioNTech gained 5.7%. The companies said they planned to submit more detailed results from the study to a scientific journal for publication.

Speaking on MSNBC this morning, White House Press Secretary Jen Psaki said the administration will “let the FDA work through the approval process, but there’s no question that this announcement this morning is good news.”

In people 16 and older, Pfizer’s and BioNTech’s messenger RNA vaccine was 95% effective at preventing symptomatic cases in a final-stage trial, leading to its emergency authorization late last year. The other messenger RNA vaccine on the market, from Moderna Inc., is currently authorized for people 18 and up and was 94% effective in its final-stage trial. Both vaccines require people to get two shots.

Earlier this month, both Pfizer and Moderna began trials of their vaccines in kids under 12. Meanwhile, Moderna is also studying its vaccine in adolescents ages 12 to 17. That trial is fully enrolled, and is on track to yield updated data around mid-year 2021, Moderna said.

This article was provided by Bloomberg News.