Influenza vaccination mitigates severe complications in hospitalized patients: A ten-year observational study, Spain, 2009-2019

•Influenza Vaccination Lowers Complication Risk: Spanish study finds vaccination reduces severe complications in flu patients.•Effective Defense Against Respiratory Issues: Vaccination lowers pneumonia, ARDS, and organ failure risk.•Substantial Decrease in ICU Admissions: Influenza vaccination linked to fewer ICU admissions, easing health care strain.•Strengthening Influenza Prevention Strategies: Research emphasizes enhancing vaccination coverage for maximum effectiveness.•Age and Comorbidities Impact Disease Severity: Advanced age and specific comorbidities contribute to severe influenza cases, requiring tailored prevention.