Adolescents had a higher incidence of post-vaccine myocarditis and pericarditis than children.
Myocarditis and pericarditis only occur after vaccination and not after COVID-19 infection, according to a recent preprint led by researchers at Oxford University, which compared health outcomes among COVID-vaccinated and unvaccinated children.
“Whilst rare, all myocarditis and pericarditis events during the study period occurred in vaccinated individuals,” the authors wrote. There were no deaths from myocarditis or pericarditis.
The study evaluated over 1 million English children aged 5 to 11 and adolescents aged 12 to 15. Vaccinated minors were compared to an equal number of unvaccinated, and children who took one dose were also compared to those who took two doses.
Despite having higher chances of heart inflammation, vaccinated adolescents had significantly lower chances of testing positive for COVID-19 and needing COVID-related hospitalization and critical care compared to their unvaccinated counterparts. Vaccinated children, however, were not substantially different from unvaccinated children in terms of COVID-19 infection and hospitalization.
Additionally, “COVID-19-related hospitalisation, and critical care attendance were rare in both adolescents and children and there were no COVID-19 related deaths,” the authors observed.
18 Cases
The study analyzed data from the National Health Service (NHS) England’s OpenSAFELY-TPP database, which covers 40 percent of English primary care practices.
Vaccinated adolescents and children were matched to unvaccinated cohorts and followed for 20 weeks to compare positive COVID-19 tests, hospitalizations, COVID-19 critical care, adverse events, and non-COVID hospitalizations.
England’s data showed that myocarditis and pericarditis were only documented in the vaccinated. These results contradict data from other studies that showed a higher incidence of myocarditis after COVID-19 infection.
Adolescents had a higher incidence of post-vaccine myocarditis and pericarditis than children.
There were 15 cases of pericarditis and three cases of myocarditis among more than 839,000 vaccinated children and adolescents. All of the myocarditis and 12 pericarditis cases appeared in the adolescent cohort.
Except for three pericarditis cases, all other cases occurred after the first vaccine dose. More than half of the adolescents with pericarditis and myocarditis were hospitalized or went to the emergency room. It is unknown how many adolescents needed critical care, though the maximum length of stay for myocarditis treatment was one day.
By Marina Zhang
