The Food and Drug Administration is reviewing reports that suggest the coronavirus vaccine made by Moderna may cause heart problems in some teens, the company said Sunday.
Moderna requested FDA approval for the use of its vaccine in children aged 12 to 17 years in June. Adolescents would receive 100 micrograms of the vaccine – the same dose given to adults 18 years of age and older. However, the agency has not yet decided on the application, which has given rise to speculation about the reasons for the delay.
In a statement Sunday, Moderna said the FDA “requires additional time to evaluate recent international analyzes of the risk of myocarditis after vaccination.”
The European Medicines Agency approved the vaccine for use in adolescents in July. But since then, several European countries have stopped using the vaccine in people aged 30 and under, citing concerns about myocarditis – an inflammation of the heart muscle.
Moderna said more than 1.5 million young people worldwide have received their coronavirus vaccine, and the data so far do not suggest an increased risk of myocarditis. However, studies from Israel and the United States have linked both the Pfizer-BioNTech and Moderna vaccines to rare and transient cases of myocarditis, with a higher risk from the Moderna vaccine.
The FDA informed Moderna on Friday that it would need more time to assess the safety of the vaccine and possibly not make a decision before January 2022, the company said in a statement Sunday. The agency took about a month to approve the Pfizer BioNTech vaccine for children aged 12 to 15 years. This vaccine has been available to adolescents in the United States and Europe since May.
Even with the increased risk, myocarditis due to the vaccine is rare, mild and disappears quickly, noted Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia and a member of the FDA’s Vaccine Advisory Committee.
Covid-19 is much more likely to cause myocarditis, noted Dr. Offit, because the virus can infect and damage the heart mucosa. “That would be the decision point I would make for my child,” he said.
In studies from Israel and the USA, the incidence of heart problems among people who had received the Pfizer-BioNTech or Moderna vaccine is highest in men aged 16 to 29 years. The risk appears to decrease in children 12 to 15 and is expected to be even lower in younger children, said Dr. Offit.
In July, the FDA asked Pfizer-BioNTech and Moderna to enroll more children in their clinical trials to detect less common side effects. Last week, after reviewing data from a clinical trial of the Pfizer-BioNTech vaccine in children aged 5 to 11 years, the FDA approved the vaccine for that age group.
Results from Pfizer’s vaccine trials in children under 5 years of age are not expected until the fourth quarter of this year at the earliest. Last week, Moderna said its vaccine produced a strong immune response in children aged 6 to 11, who received half the adult dose. The company plans to request FDA approval for the use of the vaccine in this age group.