CureusJan 5, 2026

Rates of Heart Inflammation and Nerve Disorder in Teenagers After COVID-19 mRNA Vaccination

mRNA Technology Weekly Brief ↗PubMed ↗DOI ↗

Updated Jan 6, 2026

Abstract

Myocarditis incidence is elevated in adolescent males after the second dose of COVID-19 mRNA vaccination, with a pooled risk approximately 3.9 times higher following mRNA-1273 compared to BNT162b2.

Ten studies were included in the analysis, focusing on myocarditis and Guillain-Barré syndrome (GBS) outcomes in adolescents aged 12-19 years.
The risk of myocarditis was particularly notable in adolescent and young adult males following the second dose of the vaccine.
Global data indicated a modest association between GBS and mRNA vaccines, but this risk was substantially weaker than that associated with adenoviral vector or influenza vaccines.
No consistent evidence suggested an increased risk of GBS with mRNA vaccines in adolescents.
Overall, absolute risks of these adverse events remain low, and the outcomes of vaccination are generally favorable compared to the risks of SARS-CoV-2 infection.

Simplified

This study aimed to evaluate the incidence and risk of rare long-term adverse events, specifically myocarditis and Guillain-Barré syndrome (GBS), in adolescents (12-19 years) following COVID-19 mRNA vaccination. We systematically searched MEDLINE, Embase, Cochrane CENTRAL, and Scopus, supplemented by trial registries and reference lists (PROSPERO: CRD420251045173). Eligible studies included randomized controlled trials (RCTs), cohort studies, case-control studies, self-controlled case series, and pharmacovigilance database analyses reporting myocarditis or GBS outcomes in adolescents receiving BNT162b2 or mRNA-1273. The search was conducted in June 2025, and all published studies were included. Risk of bias was assessed using the Cochrane RoB-2 tool, Newcastle-Ottawa Scale, or adapted criteria for pharmacovigilance studies. Effect measures were expressed as incidence rate or incidence rate ratios (IRRs) with 95% confidence intervals (CIs). Meta-analyses were conducted using random-effects models. Ten studies met the inclusion criteria. Myocarditis incidence was elevated in adolescent and young adult males, particularly after the second dose. Pooled analyses indicated a higher risk with mRNA-1273 compared to BNT162b2 (pooled IRR ≈ 3.9), although heterogeneity was very high (I² > 95%). For GBS, global pharmacovigilance data suggested only a modest association with mRNA vaccines (ROR 9.66), substantially weaker than for adenoviral vector or influenza vaccines. COVID-19 mRNA vaccination in adolescents is associated with a small but measurable increased risk of myocarditis, particularly in males, after the second dose, with a higher incidence following mRNA-1273. No consistent evidence of increased GBS risk was observed. Absolute risks remain low, and outcomes are generally favorable compared to SARS-CoV-2 infection. Continued surveillance and long-term follow-up are warranted.

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Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work.

PubMed

Rates of Heart Inflammation and Nerve Disorder in Teenagers After COVID-19 mRNA Vaccination

Abstract

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