Moderna has started dosing adolescent participants in a phase 2/3 trial evaluating vaccine candidate mRNA-1273, planning to enroll 3,000 U.S. volunteers aged 12 to 17.

The randomized, controlled study, conducted in partnership with the Biomedical Advanced Research and Development Authority, will evaluate the vaccine’s safety, efficacy and reactogenicity in healthy adolescents via a two-dose regimen administered 28 days apart.

The Cambridge, Mass., drugmaker will follow up with participants for 12 months after they receive the second dose and said it plans to have data available in spring to support the vaccine’s use ahead of the 2021 school year.