Influenza is the fourth leading cause of death among elderly individuals.
In the elderly, however, the diagnosis of influenza can be difficult because typical clinical signs such as fever and cough may not be present. Resolution of the illness typically occurs after several days , but cough and malaise can persist for 2 or more weeks. The effectiveness of this vaccine depends primarily on the age and immunocompetence of the recipient and the degree of similarity between the virus strains contained in the vaccine and those circulating in the environment. The potential benefits of influenza vaccination in preventing serious illness, hospitalization, and death outweigh the possible risks for developing vaccine-associated Guilan Barre syndrome. No evidence indicates that the case fatality ratio for such complication differs among vaccinated and not vaccinated elderly.