Influenza vaccination and mortality from bronchopneumonia in the elderly.

In a three-year influenza vaccination programme carried out among elderly patients these were found to have a lower haemagglutination-inhibiting antibody level and a poorer serological response to vaccination than younger persons in the same city. Although there was little difference in overall respiratory illness between the vaccinated and unvaccinated groups until the third year of observation, those who received vaccine showed a substantially smaller incidence of bronchopneumonia and a significantly lower mortality than those not so protected. The observations are believed to justify the giving of influenza vaccine in this age-group.