Myopericarditis incidence related to COVID-19 vaccination remains low in young people
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The incidence of myopericarditis among adolescents and young adults who received mRNA COVID-19 vaccines is very low, according to a systemic review and meta-analysis published in JAMA Pediatrics.
The study, which pooled evidence from a large international cohort, is the latest to examine cardiac injury in young people following vaccination.
“Despite the lack of severe complications commonly associated with COVID-19 mRNA vaccination, vaccine hesitancy remains high, and some parents still hesitate to vaccinate their children against COVID-19,” Jun Yasuhara, MD, post-doctoral scientist and pediatric cardiologist at the Center for Cardiovascular Research at the Abigail Wexner Research Institute at Nationwide Children’s Hospital in Columbus, Ohio, told Healio.
“One of their biggest concerns is myocarditis,” Yasuhara continued. “We know the risk of developing myocarditis after SARS-CoV-2 infection is higher than after COVID-19 mRNA vaccination, but the clinical pictures of COVID-19 vaccine-associated myopericarditis, such as the incidence rate and early outcomes, remain unclear, which inspired us to examine this issue.”
Yasuhara and colleagues searched PubMed and Embase databases through August 2022 and identified 23 observational studies, including 12 retrospective or prospective cohort studies and 11 case series. There were 854 patients (mean age, 15.9 years; age range, 12-20 years; 90.3% male) across all studies who had received a diagnosis of COVID-19 vaccine-associated myopericarditis.
“The primary outcomes of this study were the clinical features and early outcomes of myopericarditis in adolescents and young adults following COVID-19 vaccination, including incidence, cardiac findings, in-hospital mortality, hospitalization, ICU admission and treatments,” Yasuhara said.
The researchers found that myopericarditis occurred more often after the second dose than the first.
Most patients — 84.4% (95% CI, 80.5%-88.3%) — had preserved left ventricular (LV) function. Of the 15.6% (95% CI, 11.7%-19.5%) of patients with left ventricular (LV) systolic dysfunction, “most (14.1% [95% CI, 10.2%-18.1%]) were mild, and only 1.3% (95% CI, 0%-2.6%) of patients had severe LV systolic dysfunction,” according to Yasuhara. Severe LV systolic dysfunction was defined as having a left ventricle ejection fraction of less than 35%.
Additionally, cardiac magnetic resonance (CMR) imaging revealed late gadolinium enhancement (LGE) in 87.2% (95% CI, 79.8%-94.7%) of patients, which Yasuhara said was “surprising.”
“The persistence of LGE indicates the potential myocardial fibrosis and could be a risk factor for adverse cardiac events in patients with myocarditis, but further studies are needed to investigate the association of CMR findings and long-term outcomes,” Yasuhara said.
Ultimately, the review showed a low incidence rate of 0.6 to 10 per million persons after the first dose, and 12.7 to 118.7 per million persons after the second dose. It also found largely favorable early outcomes of COVID-19 mRNA vaccine-associated myopericarditis in adolescents and young adults, “demonstrating that most patients had no left ventricular systolic dysfunction or mild left ventricular systolic dysfunction with recovery,” Yasuhara said.
“Our findings could help improve understanding of myopericarditis among adolescents and young adults and decision-making for parents,” Yasuhara said. “Further studies are needed to investigate the long-term outcomes of association of myopericarditis after COVID-19 vaccination in adolescents and young adults, the significance of CMR findings such as LGE, the influence of interdose interval, and the findings from other types of vaccines such as [Moderna’s] mRNA-1273.”
Editor’s note: The risk for myocarditis associated with COVID-19 vaccination is addressed in our vaccine discussion guide, available here .
Reference:
Yasuhara J, et al. JAMA Pediatr. 2022;doi:10.1001/jamapediatrics.2022.4768.