A small number of teen and young adult recipients of mRNA-based coronavirus vaccines have developed a heart issue, per the New York Times. The incidence of myocarditis, or inflammation of the heart muscle, has occurred frequently enough to get the attention of the CDC, though. In a statement, the CDC Advisory Committee said such incidents, mostly seen in male adolescents and young adults, were not found in more cases than would be expected in the population and the condition frequently goes away on its own, per Reuters. However, the statement said the committee believes healthcare providers should be aware of the "potential adverse event."
The CDC did not offer how many patients experienced myocarditis, nor did they reveal which mRNA vaccine was administered to those patients. However, only the Moderna and Pfizer/BioNTech mRNA vaccines have been given emergency use authorization. Of those, only Pfizer's is authorized for use in children 12 and up. The CDC said the condition typically appears within four days of receiving the vaccine. As the Guardian notes, this is not the first time we've heard of such potential complications. An Israeli investigation back in April noted a small number of myocarditis incidents in people who'd received the Pfizer vaccine. Their report found it occurred in patients up to the age of 30. The CDC responded at the time, saying it did not see a link between the vaccine and the heart issue. (Read more coronavirus vaccine stories.)