Vaccination is linked to a 41% reduced risk of being hospitalized for influenza, according to a multi-hospital study of older U.S. adults.
The researchers evaluated the effectiveness of the 2019-2020 influenza vaccine in a group of 3,000 adults with a median age of 63. Among them, 67% had received a flu vaccination. Along with apparently lowering the odds of hospitalization, vaccination also was 40% effective against influenza type A (H1N1) viruses (although not in one subgroup), and it was 33% protective against type B viruses, reported Manish M. Patel, M.D., of the Centers for Disease Control and Prevention, and colleagues.
The study population included patients with acute respiratory illness admitted to 14 hospitals. These participants were tested for influenza viruses by reverse transcription polymerase chain reaction tests. Investigators estimated vaccine effectiveness by comparing the odds of current-season influenza vaccination in participants who tested positive for influenza with vaccine effectiveness in controls who tested negative.
Full findings were published in the Journal of Infectious Diseases.