A preprint study linked heart inflammation in children to the COVID-19 vaccine.

Only children who received the vaccine suffered from heart inflammation, not those who had the virus and remained unvaccinated.

Researchers compared the medical data of those between the ages of 5-11 in the United Kingdom. More than 1 million records were assessed.

“Among both adolescents and children, myocarditis and pericarditis were documented only in the vaccinated groups,” the study found.

While only COVID-vaccinated children had heart issues, such as myocarditis and pericarditis, they were less likely to be hospitalized from the virus.

The efficacy of the vaccine, however, was low.

“BNT162b2 vaccination in adolescents reduced COVID-19 A&E attendance and hospitalisation, although these outcomes were rare,” the researchers wrote. “Protection against positive SARS-CoV-2 tests was transient.”