A 21-winter seasons retrospective study of antibody response after influenza vaccination in elderly (60–85 years old) and very elderly (>85 years old) institutionalized subjects

ABSTRACTInfluenza vaccination is considered the best mean for preventing the higher rates of mortality associated with influenza virus infection in the elderly as compared with younger people. Since the number of very elderly subjects, aged >85 years, is rapidly increasing, and some authors reported increments in influenza-associated mortality with age, the aim of this study was to increase the limited information available on the immunogenicity of the influenza vaccines in this age group. This was a retrospective study which analyzed the antibody response induced by commercially available trivalent inactivated influenza vaccines in 1491 elderly subjects (60–85 years old) and 1139 very elderly subjects (>85 years old) during 21 winter seasons included between 1993–1994 and 2014–2015. The antibody response of the two age groups was, in most instances, acceptable according to the Committee for Medical Products for Human Use and comparable. In accordance with previous data obtained in the elderly, the use of...