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The 2024–2025 influenza season was characterized as having high severity, and in research published in Open Forum Infectious Diseases, researchers found flu shots provided protection not just against hospitalization but also against emergency department (ED) and urgent care (UC) visits during that time. They evaluated influenza vaccine effectiveness using data from 7 healthcare systems in 8 states across 102,854 ED/urgent care visits among children and 233,411 visits among adults. Overall, vaccination was 54% effective against influenza-associated ED/urgent care encounters in children and 49% effective in adults. Among children, effectiveness was higher for those aged 6 months–4 years (61%) than those aged 5–17 years (47%). Among adults, effectiveness was 51% for ages 18–49 years, 48% for ages 50–64 years, and 44% for those 65 years and older. Protection against influenza-associated hospitalization and ED/UC encounters persisted for 120 days or more after vaccination, according to the authors. In general, the seasonal flu vaccine is usually 40%–60% effective.
Parse the numbers: In this study, encounters involving both an ED and UC visit within 7 days were excluded from the ED-only and UC-only analyses. What’s interesting is that of 5,215 influenza-positive encounters that were seen in urgent care, 1,045 (20%) were among patients who were vaccinated. Of the 47,996 influenza-negative urgent care encounters, 15,738 (33%) were vaccinated.