The study examined the association between vaccination against COVID-19 and sudden death in apparently healthy people aged 12–50 years in Ontario, Canada, from April 1, 2021, to June 30, 2023. Of 6,365,451 eligible individuals, they identified 4,963 cases of sudden death (0.08%), with a mean age of 36 years. Cases were matched to five controls by age, sex, region, and income, adjusting for factors such as SARS-CoV-2 testing, influenza vaccination, and comorbidities. In the primary analysis, vaccination was associated with a lower risk of sudden death (adjusted odds ratio aOR = 0.57; 95% CI [0.53, 0.61]; p < 0.001), including vaccination 6 weeks before death (aOR = 0.63; 95% CI [0.55, 0.72]). The findings were confirmed by sensitivity analyzes for age under 40 years, in-hospital deaths, and after excluding opioids. A self-controlled case series analysis did not show an increased risk after the 1st, 2nd, or 3rd dose. The study's conclusion does not support the hypothesis that COVID-19 vaccines increase the risk of sudden cardiac death in young, healthy adults.