Cardiac Safety Signals Following COVID-19 Vaccination in Children and Adolescents: A Nationwide VAERS Analysis,...

Although COVID-19 is generally mild in children and adolescents, vaccination remains essential to reduce infection and transmission. However, real-world evidence regarding reported cardiac adverse events (AEs) followingCOVID-19 vaccination in pediatric populations remains limited.

Using the Vaccine Adverse Event Reporting System (VAERS, 2020-2025), we analyzed reports of cardiac AEs following COVID-19 vaccination in children and adolescents. Disproportionality analyses were conducted at the system organ class and preferred term levels to detect signal strength. Univariate and multivariate logistic regression was employed to explore influencing factors of COVID-19 vaccine-relate cardiac AEs, and time-to-onset (TTO) patterns were assessed. Disproportionality metrics, including the reporting odds ratio (ROR), proportional reporting ratio (PRR), and information component (IC), were interpreted as measures of reporting disproportionality rather than incidence, absolute risk, or causality, because VAERS lacks denominator vaccination counts.

From December 2020 to August 2025, 72,922 vaccine-related AE reports were identified, including 4266 cardiac events. Cardiac AE reports were more likely to involve serious outcomes than non-cardiac AE reports. Disproportionate reporting signals were observed for cardiac disorders overall (ROR: 3.57; PRR: 3.52; IC: 0.45). At the preferred term level, myocarditis, pericarditis, palpitations, and tachycardia consistently showed significant signals. Cardiac AE reports were predominantly observed in adolescents aged 12 to 17 years and were more frequent in males. Older age (12-17 years), male sex, underlying comorbidities, a history of allergies, receipt of a two-dose vaccination series, and the Pfizer-BioNTech vaccine were independently associated with increased odds of cardiac adverse events. Cardiac AEs had a longer median TTO than non-cardiac AEs (1 versus 0 day); however, this 1-day absolute difference should be interpreted as statistically detectable but clinically modest.

The VAERS-based pharmacovigilance analysis identified disproportionate reporting signals for cardiac AEs following COVID-19 vaccination in children and adolescents, particularly myocarditis and pericarditis, with disproportionate reporting most pronounced among adolescent males. These findings should be interpreted as signal detection rather than confirmation of increased incidence, absolute risk, or causality. Enhanced post-vaccination monitoring and further validation using denominator-based active surveillance systems are warranted.