Influenza causes substantial mortality and morbidity in elderly people, particularly those with chronic diseases. Excess deaths during influenza epidemics are not limited to obvious causes such as influenza and pneumonia but also include circulatory and other respiratory causes.^w1 People in elderly care homes and hospital wards are at particular risk, because high risk individuals are concentrated in an environment susceptible to the spread of respiratory pathogens. In this week's BMJ, Hayward and colleagues report the impact of vaccinating healthcare workers in elderly peoples homes on mortality in residents.1

Most developed countries offer elderly people vaccination against predicted influenza strains for the next season.2 However, the age related decline of immune function reduces the ability of elderly patients to respond to the influenza vaccine,3 and the vaccine is less effective in patients with chronic diseases.4 Also, as most of the evidence in elderly people comes from database cohort studies, effects may have been overestimated because healthier people are more likely to be vaccinated and the reported estimates may not have been fully adjusted for …