COVID-19 Vaccination Continues to Be Effective in Preventing COVID-19–Associated Clinical Outcomes for U.S. Veterans

Background: Given public uncertainty about the continued value of annual COVID-19 vaccines, and declining vaccine uptake, real-world data regarding vaccine effectiveness are needed. Objective: To evaluate the effectiveness of the combination of COVID-19 and influenza vaccination, versus influenza vaccination alone, on clinical outcomes. Design: Observational study. Methods: Veterans Affairs health care databases were used to compare clinical outcomes in patients receiving the 2024–2025 COVID-19 vaccine and the seasonal influenza vaccine on the same day with outcomes in those who received only the influenza vaccine. Patients were included if they had a clinical encounter for vaccination between September 3 and December 31, 2024, and had a primary care visit within the prior 18 months. The 3 primary outcomes included: COVID-19 emergency department (ED) visit (within 24 hours of a positive test), COVID-19–associated hospitalization (within 2 to 7 days of a positive test), and COVID-19–a more...