ANNUALLY REPEATED INFLUENZA VACCINATION IMPROVES HUMORAL RESPONSES TOSEVERAL INFLUENZA-VIRUS STRAINS IN HEALTHY ELDERLY

The benefit of annually repeated influenza vaccination on antibody for mation is still under debate. In this study the effect of annually rep eated influenza vaccination on haemagglutination inhibiting (HI) antib ody formation in the elderly is investigated. Between 1990 and 1993 he althy young and elderly, both selected by the SENIEUR protocol, were v accinated consecutively with commercially available influenza vaccines . The elderly had a lower HI antibody response after one vaccination a s compared to the young against the A/Taiwan/1/86 (H1N1), B/Yamagata/1 6/88 and B/Panama/45/90 strains. Annually repeated vaccination did not result in a decrease of the HI antibody titres against the A and B va ccine strains in both age groups. Moreover, the elderly had a signific antly higher HI titre against the B strains after the second vaccinati on as compared to the first, resulting in comparable HI titres for you ng and elderly. Thus, annually repeated vaccination has a beneficial e ffect on the antibody titre against influenza virus and can contribute to a better antibody-response in the elderly. (C) 1997 Elsevier Scien ce Ltd.