COVID vaccines not tied to risk of sudden death, study shows

Data show that young, healthy people have no additional risk of sudden death if they are vaccinated against COVID-19, contrary to myths that continue to circulate widely on social media.

In fact, healthy adolescents and young adults vaccinated against COVID-19 were 43% less likely to experience sudden death than non-vaccinated people, according to a Canadian case-control study published last week in PLOS Medicine.

Researchers focused on Ontario residents ages 12 years to 50 years old. None had chronic conditions that increase the risk of death from COVID-19.

Sudden death in this population was incredibly rare, occurring in 4,806 people––or 0.08%––of the nearly 6.4 million people whose medical records were included in the study.

The study authors matched each person who died to five living people based on age, sex, region, and neighborhood income. Researchers defined a death as one that occurred outside the hospital or within 24 hours of arriving at a hospital with a final diagnosis of cardiac arrest from April 1, 2021, to June 30, 2023.

The researchers found no increased rate of sudden death in people within six week of the first, second, or third vaccine dose.

Findings add to growing evidence of vaccine safety

The new research confirms earlier studies that also have found no link between COVID vaccinations and sudden death in young people.

A study published in JAMA Network Open in 2025, for example, found no increased risk of sudden cardiac arrest or sudden death in young athletes during or after the pandemic.

Research published in 2024 also found no link between mRNA COVID-19 vaccination and sudden cardiac death. The study, which appeared in the US Centers for Disease Control and Prevention’s flagship publication, Morbidity and Mortality Weekly Report, examined death certificates and immunization records of previously healthy young adults in Oregon.