Teenage recipients of mRNA-based COVID-19 vaccines faced an elevated risk of serious adverse events, when having more than one shot of the vaccine.
Teenage recipients of mRNA-based COVID-19 vaccines faced an elevated risk of serious adverse events, including heart inflammation, appendicitis, and allergic reactions starting with the second dose of the vaccine, according to a Norwegian study of approximately 496,432 adolescents aged 12 to 19, published in Scientific Reports on March 27, 2026.
No significant increase in adverse events was observed after the first dose, but the second dose was linked to higher incidences of myocarditis (primarily in 18- to 19-year-olds), swollen lymph nodes, allergic reactions, and, among those without prior SARS-CoV-2 infection, an elevated risk of epilepsy and convulsions.
Age-specific patterns were observed: 16- to 17-year-olds showed more cases of acute appendicitis, while heart inflammation was concentrated in older teens.
The study (1), funded by the Norwegian Institute of Public Health, noted that most statistically significant associations were low in number and called for further research on age-specific effects of mRNA vaccines.
While organizations like the Vaccine Safety Research Foundation urged regulatory action, experts such as Jeffrey Morris of the University of Pennsylvania stated the findings align with existing evidence and the benefits of vaccination continue to outweigh the risks.
In a previous meta study (2), using data from five retrospective studies on adolescents, the pooled estimated proportion of participants who developed myocarditis and/or pericarditis was 2.33 per 100,000 of the population. This could rise to 12.2 per 100,000 depending upon the subgroup.
Sub-group analysis with sex and vaccine doses showed that male (5.35 per 100,000) and the second dose (9.71 per 100,000) had significantly higher incidence of myocarditis and/or pericarditis than female (1.09 per 100,000) and the first dose (1.61 per 100,000), respectively.
Go to: Ivermectin repeatedly linked to lower Covid levels and lower Covid deaths
*******
References
- Adverse events following SARS-CoV-2 mRNA vaccination in norwegian adolescents; Vilde Bergstad Larsen et al; Sci Rep 16, 10878 (2026)
- Efficacy and Safety of COVID-19 Vaccines in Adolescents: Systematic Review of Randomized Controlled Studies and Observational Studies; Soo-Han Choi et al; Pediatr Infect Vaccine. 2024 Apr;31(1):12-24. English; Published online Apr 04, 2024.
