Immunogenicity of an inactivated split influenza vaccine in institutionalized elderly patients.

The immunogenicity of influenza vaccination in elderly institutionalized patients, with a variety of clinical disorders, was tested in an open multicenter study involving 495 people (mean age 80 years). Vaccination with an inactivated split influenza vaccine (Fluarix) was clinically well tolerated. For all age ranges and all strains of virus, the vaccine elicited a humoral response which surpassed the European Community requirements for influenza vaccines in adults over 60 years. The geometric mean titers for all vaccine strains were significantly increased 28 days after vaccination, and remained higher than prevaccination levels after 6 months. These immunological parameters were unaffected by the clinical status of the patients.