Adolescents had a higher incidence of post-vaccine myocarditis and pericarditis than children.

https://www.theepochtimes.com/health/myocarditis-and-pericarditis-only-appear-after-covid-vaccination-nhs-preprint-shows-5659341?

AND

OpenSAFELY: Effectiveness of COVID-19 vaccination in children and adolescents

https://www.medrxiv.org/content/10.1101/2024.05.20.24306810v1