H1N1 vaccine 50% effective at preventing hospitalization

A single dose of monovalent non-adjuvanted influenza A (H1N1) pdm09 vaccine was 50% effective at preventing hospitalization related to the infection, researchers from the CDC have found. According to the report in Clinical Infectious Diseases, recent data have suggested that such vaccines were 69% effective at preventing influenza during the 2009 pandemic. Studies on vaccine effectiveness against hospitalization have ranged from 49% to 90%. The researchers used CDC’s Influenza Surveillance Network to identify patients with laboratory-confirmed H1N1 infections who were matched with two community controls. The patients and the controls underwent structured telephone interviews, which the researchers used, along with medical and hospital records, to determine patient characteristics, vaccination status and the presence of medical conditions associated with increased risk for influenza complications. The study included 217 patients who were hospitalized with influenza from Dec. 5, 2009, to April 30, 2010. Among these patients, 14% were immunized compared with 22% of the 413...