Moderna Inc, whose vaccine is authorized for adults 18 and older, said it will submit the findings of its adolescent study to the US Food and Drug Administration and other regulators for emergency use authorization in early June.
US regulators took about a month to review a similar study from Pfizer/BioNtech, which was authorized for ages 12-15 on May 10. If Moderna gets the same treatment, its authorization would come in early July.
Most children with COVID-19 develop only mild symptoms or no symptoms. Yet children remain at risk of becoming seriously ill, and they can spread the virus. Widely vaccinating 12- to 18-year-olds could allow US schools and summer camps to relax masking and social distancing measures suggested by the CDC.
“We are encouraged that mRNA-1273 was highly effective at preventing COVID-19 in adolescents," Stéphane Bancel, Moderna's chief executive, said in a statement.
Moderna's trial evaluated the vaccine in 3,732 adolescents aged 12 to 17, two thirds of whom got the vaccine and one third of whom got a placebo. The main goal was to produce an immune response on par with that seen in the company's large, Phase 3 trial in adults, which was 94.1% effective at preventing COVID-19.
Two weeks after the second dose, researchers found no cases of COVID-19 in the vaccine group compared to 4 cases in the placebo group, resulting in a vaccine efficacy of 100%, based on case definitions from the company's adult trial.
Using a case definition from the US Centers for Disease Control and Prevention, which requires only 1 COVID-19 symptom, the vaccine was found to be 93% effective, suggesting the vaccine may be protective against cases with milder symptoms, the company said.
The researchers found no new safety issues. The most common side effects after the second dose were headache, fatigue, body aches and chills.
The company said it is still accumulating safety data. All study participants will be monitored for 12 months after their second dose to determine long-term protection and safety.
Moderna said it plans to submit the data to a peer-reviewed publication. The company is currently testing its vaccine in children as young as 6 months of age.
In addition to the United States, Pfizer's vaccine is also authorized for use in younger teens aged 12 to 15 in Canada and Algeria.