Concerns about the long-term effects of mRNA COVID-19 vaccines have persisted even as uptake decreased globally throughout 2024. Now, a large-scale study from France offers renewed evidence supporting the vaccines’ safety profile, adding to a growing body of research on the subject. Published in JAMA Network Open on December 4, 2025, the analysis of nearly 29 million individuals provides critical data for public health officials as they navigate ongoing vaccination strategies and prepare for future variants.
A comprehensive French study has reinforced the long-term safety of mRNA COVID-19 vaccines, offering crucial data as public health officials continue to monitor vaccine impacts globally. The research, published December 4, 2025, in JAMA Network Open, provides robust scientific evidence addressing ongoing discussions about the long-term effects of these widely used vaccines.
The study, based on data from the French National Health Data System, compared mortality rates among vaccinated and unvaccinated adults aged 18 to 59. Researchers found that receiving the Pfizer-BioNTech or Moderna mRNA vaccines did not increase the risk of death from all causes – in fact, it significantly lowered it.
Study Included Over 28 Million Individuals
The research team analyzed data from 22,767,546 individuals who received their first dose of an mRNA vaccine between May 1 and October 31, 2021. This vaccinated group was compared to 5,932,443 unvaccinated individuals as of November 1, 2021. Participants were followed for an average of 45 months, or approximately 4 years. The findings revealed a higher survival rate among those who received the vaccine.
Key Findings
The risk of death from all causes was 25% lower in the vaccinated group.
COVID-19-related deaths were reduced by 74% among vaccinated individuals.
Even when examining deaths not related to COVID-19, the vaccinated group experienced a roughly 24% lower risk of mortality.
No Increase in Cancer or Cardiovascular Deaths
The study found no evidence suggesting that mRNA vaccines increased deaths related to cancer or cardiovascular disease. In fact, death rates from these causes were also lower in the vaccinated group. This research is particularly noteworthy as it focused on the 18–59 age group, where COVID-19 illness is often milder and vaccine necessity has been frequently debated. The four-year follow-up period demonstrates that the vaccines did not create an additional mortality risk in this age group, and instead offered a protective effect.
These findings offer valuable long-term data that can inform public health strategies and address lingering concerns about vaccine safety, particularly as booster recommendations evolve.
