A comprehensive review of the billions of COVID-19 vaccine doses made with mRNA technology shows that these vaccines are safe and effective.
Vaccine skepticism increased during the COVID-19 pandemic, with some mistrust specifically directed at mRNA vaccines. The global health emergency marked the first time mRNA technology was approved for large-scale use, and people questioned its safety and trustworthiness.
But the new study, published [on June 30, 2026] in The Lancet, reaffirms that serious adverse events, such as anaphylaxis (a severe allergic reaction) or myocarditis (inflammation of heart muscle), are rare after receiving an mRNA COVID shot. Researchers found that the odds of such medical emergencies were “consistently outweighed by the substantial protection” the vaccines provide against severe disease, hospitalization, and death. That includes among people who are pregnant or immunocompromised.
Because mRNA vaccines are faster to produce and easier to customize, the findings have promising implications for influenza, respiratory syncytial virus (RSV), and other infectious diseases, as well as for personalized cancer vaccines and other RNA-based therapeutics.
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“mRNA vaccines have already changed how we respond to global health threats,” said senior author Manish Sadarangani, DPhil, in a University of British Columbia news release. “With sustained innovation, strong safety monitoring, and a commitment to equitable access, they can play a major role in preventing disease and improving health.”
