The findings stem from a U.S. study involving over 3,700 kids, called TeenCOVE. Moderna intends to submit the findings to regulators around the world in early June.
"We are encouraged that mRNA-1273 was highly effective at preventing COVID-19 in adolescents. It is particularly exciting to see that the Moderna COVID-19 vaccine can prevent SARS-CoV-2 infection," said Stéphane Bancel, CEO of Moderna, in a statement posted Tuesday. "We will submit these results to the U.S. FDA and regulators globally in early June and request authorization. We remain committed to doing our part to help end the COVID-19 pandemic."
In the late-stage study, 3,732 kids were randomized to receive 100 microgram doses of the previously authorized vaccine or placebo. After two doses, there were no cases of COVID-19 in the vaccine group, compared to four cases in the placebo group, translating to a vaccine efficacy of 100% beginning 14 days following the second dose.
Moderna said the jab was "generally well tolerated" with a safety and tolerability profile "generally consistent" with that seen in a prior clinical trial with adults. Most side effects were mild or moderate in severity, and injection site pain was reported as the most common local side effect. Fully vaccinated participants experienced headache, fatigue, myalgia and chills.
The company continues to collect safety data, and an independent safety committee is monitoring the data. Study participants will be followed for 12 months post-second dose to determine long-term protection and safety, Moderna said.
The news comes after Pfizer announced in late March that its COVID-19 vaccine was safe and 100% effective in kids aged 12-15. Pfizer's jab received expanded FDA emergency approval on May 10.