WashU Medicine Jun 15 2026 A new study led by researchers at Washington University School of Medicine in St. Louis has found that an investigational mRNA influenza vaccine helps the immune system recognize a wider range of influenza viruses than today's standard flu shot, offering stronger and potentially longer-lasting protection. About 1 billion people worldwide get the flu each year. Flu shots reduce hospitalizations and deaths, but they are less effective when the vaccine strains don't