Moderna announced Thursday they have started giving teenagers their COVID-19 vaccine as part of their study on how the vaccine works in those under 18.

Pfizer, the other vaccine maker with an emergency use request for their COVID-19 vaccine in adults before the FDA, started including teens in their trial in October.

In the Moderna’s press release, they say the Phase 2/3 study of the mRNA vaccine is now underway and is being conducted on children between the ages of 12 and 18.

“We are pleased to begin this Phase 2/3 study of mRNA-1273 in healthy adolescents in the U.S. Our goal is to generate data in the spring of 2021 that will support the use of mRNA-1273 in adolescents in advance of the 2021 school year,” said Stéphane Bancel, Chief Executive Officer of Moderna in a company statement. “We hope we will be able to provide a safe vaccine to provide protection to adolescents so they can return to school in a normal setting.”

The Phase 2/3 study from Moderna is being done to test the safety and immunogenicity of the two-dose vaccine they submitted to the FDA for emergency use approval last month.

They plan to enroll about 3,000 teenagers in the U.S. in the trial, with each receiving either a placebo or the vaccine in two doses, 28 days apart.