NEW YORK CITY (NewsNation Now) — Pfizer Inc and German partner BioNTech SE said Wednesday its COVID-19 vaccine is safe and strongly protective in kids as young as 12, paving the way for them to seek U.S. emergency use authorization in the coming weeks.

In the trial of 2,260 adolescents aged 12 to 15, there were 18 cases of COVID-19 in the group that got a placebo shot and none in the group that got the vaccine, resulting in 100% efficacy in preventing COVID-19, the companies said in a statement.

It’s a small study, that hasn’t yet been published, so another important piece of evidence is how well the shots revved up the kids’ immune systems. Researchers reported high levels of virus-fighting antibodies in the 12- to 15-year olds.

Most COVID-19 vaccines being rolled out worldwide are for adults, who are at higher risk from the coronavirus. Pfizer’s vaccine is authorized for ages 16 and older. But vaccinating children of all ages will be critical to stopping the pandemic — and helping schools, at least the upper grades, start to look a little more normal after months of disruption.

Kids had side effects similar to young adults, the company said. The main side effects are pain, fever, chills and fatigue, particularly after the second dose. The study will continue to track participants for two years for more information about long-term protection and safety.

This paves the way for the companies in the coming weeks to ask the U.S. Food and Drug Administration and European regulators to allow emergency use of the shots starting at age 12.

Pfizer hopes that vaccinations of the group could begin before the next school year, Albert Bourla, Pfizer’s chairman and chief executive, said in a statement.

“We share the urgency to expand the use of our vaccine,” Bourla said in a statement. He expressed “the hope of starting to vaccinate this age group before the start of the next school year” in the United States.

Pfizer isn’t the only company seeking to lower the age limit for its vaccine. Results also are expected soon from a U.S. study of Moderna’s vaccine in 12- to 17-year-olds.

But in a sign that the findings were promising, the FDA already allowed both companies to begin U.S. studies in children 11 and younger, working their way to as young as 6-month-old.

AstraZeneca last month began a study of its vaccine among 6- to 17-year-olds in Britain. Johnson & Johnson is planning its own pediatric studies. And in China, Sinovac recently announced it has submitted preliminary data to Chinese regulators showing its vaccine is safe in children as young as 3.

While most COVID-19 vaccines being used globally were first tested in tens of thousands of adults, pediatric studies won’t need to be nearly as large. Scientists have safety information from those studies and from subsequent vaccinations in millions more adults.

One key question is the dosage: Pfizer gave the 12-and-older participants the same dose adults receive while testing different doses in younger children.

It’s not clear how quickly the FDA would act on Pfizer’s request to allow vaccination starting at age 12. Another question is when the country would have enough supply of shots — and people to get them into adolescents’ arms — to let kids start getting in line.

Supplies are set to steadily increase over the spring and summer, at the same time states are opening vaccinations to younger, healthier adults who until now haven’t had a turn.

About 53.4 million people, or 16.2% of the U.S. population, have been fully inoculated with COVID-19 vaccines made by Pfizer Inc/ BioNTech SE, Moderna Inc and Johnson & Johnson, according to CDC data. 28.9% of the U.S. population, or 96 million adults had received at least one dose of a COVID-19 vaccine.