Moderna COVID-19 Vaccine Unlikely to Be Authorized for Adolescents in 2021

Moderna_Maddie Meyer/Getty Images

Maddie Meyer/Getty Images

On Friday, October 29, the U.S.Food and Drug Administration (FDA) informed Moderna that it would need more time to evaluate the company’s Emergency Use Authorization (EUA) submission for its COVID-19 vaccine for adolescents 12 to 17 years of age. The agency needs more time to look at recent international data on the risk of myocarditis as a serious side effect of the vaccine.

Myocarditis is inflammation of the heart muscle. An unpublished study by Sweden’s Public Health Agency recently found a slightly increased risk of myocarditis in young men and boys. This resulted in four countries halting vaccinations in this age group: Finland, Sweden, Denmark and Norway.

Sweden’s Public Health Agency indicated the data signaled “an increased risk of side effects such as inflammation of the heart muscle or the pericardium…. The risk of being affected is very small.”

Moderna said it didn’t have access to that data yet and estimated that more than 1.5 million adolescents had also had their COVID-19 shot and they saw no signs of increased risk of myocarditis in people under the age of 18. Moderna indicated it will “delay filing a request for EUA of mRNA-1273 at the 50-microgram dose level in the pediatric population (6-11 years of age) while the FDA completes its review of the adolescent EUA request.”

Some cases of myocarditis have been observed with both the Pfizer-BioNTech and Moderna vaccines. However, myocarditis can be caused by viral infections, including COVID-19. Incidents of myocarditis associated with COVID-19 vaccines are rare and generally mild.

Moderna filed for the EUA in June. In May, it had announced results from the Phase II/III TeenCOVE trial in adolescents. The study hit its primary immunogenicity endpoint. In almost 2,500 adolescents who received the vaccine, efficacy was 100%, meaning none were diagnosed with COVID-19.

In August, an Israeli study published in the New England Journal of Medicine reported the Pfizer-BioNTech vaccine was associated with a threefold higher risk of myocarditis, although COVID-19 infection was also linked with an even higher risk of myocarditis. In that study, myocarditis was connected to five events per 100,000 people.

The study authors wrote, “We estimated that the BNT162b2 (Pfizer-BioNTech) vaccine resulted in an increased incidence of a few adverse events over a 42-day follow-up period. Although most of these events were mild, some of them, such as myocarditis, could be potentially serious. However, our results indicate that SARS-CoV-2 infection is itself a very strong risk factor for myocarditis, and it also substantially increases the risk of multiple other serious adverse events.”

Studies seem to suggest the risk is slightly higher with the Moderna vaccine. Paul Offit, director of the Vaccine Education Center at Children’s Hospital of Philadelphia and a member of the FDA’s vaccines advisory committee, noted that COVID-19 is more likely to cause myocarditis. “That would be the decision point I would make for my child,” he said.

Currently, the Moderna vaccine is authorized for people 18 and older. The Pfizer-BioNTech vaccine is fully approved for people 16 and older, authorized for people 12 to 15, and on October 29, granted EUA for the vaccine in children ages 5 to 11. For the 5-to-11 age group, it is being reviewed by the U.S. Centers for Disease Control and Prevention (CDC)’s vaccine committee on November 2 and 3.

The European Medicines Agency (EMA) approved the Moderna vaccine for adolescents in July.

U.S. and Israel studies have observed the incidence of myocarditis to be highest in males aged 16 to 29 years. It seems to drop in the 12-to-15 age group, and likely even lower in younger children.

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