U.S. health officials are investigating whether the Moderna coronavirus vaccine causes heart inflammation following reports that the link between the two could be stronger than previously thought.
The Food and Drug Administration and the Centers for Disease Control and Prevention said they are looking into new data from Canada pointing to a higher risk of myocarditis, or inflammation of the heart muscle usually caused by viral infection, in men under 30 who received the Moderna vaccine, according to the Washington Post.
The Canadian data revealed that the Moderna vaccine was 2.5 times more likely to cause heart inflammation than the Pfizer–BioNTech vaccine.
Health officials said the data were not conclusive but that the link was being investigated.
“We have not come to a conclusion on this,” one of the people familiar with the investigation said. “The data are not slam bang.”
The CDC confirmed the investigation is ongoing and said health experts “are actively monitoring these reports, including reviewing data and medical records, to learn more and understand any relationship to COVID-19 mRNA vaccination.”
FDA spokesperson Stephanie Caccomo declined to go into details but said it would be sure to keep concerned members of the public apprised as the research develops.
“We can say that FDA is absolutely committed to reviewing data as it becomes available to us,” she said. “We have previously communicated about myocarditis and COVID-19 vaccines and if new information changes the risk/benefit profile, we will update the public accordingly.”
The FDA had to add a warning label to both the Moderna and Pfizer vaccines in June about the increased risk of myocarditis associated with the shots.
“For the young people who do [experience myocarditis after vaccination], most cases are mild, and individuals recover often on their own or with minimal treatment,” a joint statement co-signed by the Department of Health and Human Services, American Heart Association, and 16 others said.
“In addition, we know that myocarditis and pericarditis are much more common if you get COVID-19, and the risks to the heart from COVID-19 infection can be more severe,” it said.
