Antibody response to 1995-1996 influenza vaccine in institutionalized and non-institutionalized elderly women

Background: Concern about poor responsiveness to influenza vaccination by i nstitutionalized elderly people. Objective: To determine whether institutio nalized elderly volunteers develop a significant antibody response followin g influenza vaccine and to compare this response with that of non-instituti onalized subjects. Methods: The haemagglutination-inhibiting antibody respo nse after 1995-1996 influenza vaccination [A/Shangdong/9/93 (H3N2), A/Taiwa n/1/86 (H1N1), B/Panama/45/90] was estimated in 80 elderly women living in a nursing home and com pa red with that of 51 non-institutionalized women. Results: No differences were found in the prevaccination status, and, after vaccination, a significant humoral response was elicited both in instituti onalized and noninstitutionalized elderly subjects against all th ree influ enza strains tested. The immune response of institutionalized patients was satisfactory and significantly higher than that observed in non-institution alized women. These results were confirmed both by a separate analysis of h omogeneous subgroups stratified according to the presence in the two cohort s of potential causes of differential antibody response (prevaccination ant ibody titre, age, long-term drug treatment, risk factors for influenza infe ction, and physical disability) and by logistic regression analysis in orde r to adjust immune responses for the different variables. Conclusion: Influ enza vaccination is effective in elderly people living in nursing homes. Ho wever, the postvaccination antibody response to influenza vaccine is influe nced by different factors directly or indirectly related to residence.