Relationship between the response to influenza vaccination and the nutritional status in institutionalized elderly subjects.

BACKGROUND Influenza is a major health problem among elderly people in industrialized countries. Nursing homes may be a particularly good setting for outbreaks of influenza. Thus, the aim of the present study was to evaluate some aspects of the nutritional status of institutionalized elderly subjects in relation to their response to influenza vaccination. Certain aspects of the cellular immune response were also investigated. METHODS Twenty-three patients participated in this cross-sectional study. All patients were vaccinated on day 0 with FluviralR, 1994-95 preparation: A/Shangdong/09/93, A/Texas/36/91, B/Panama/45/90. At the same time the prevaccination antibody titer, the nutritional status by the Mini Nutritional Assessment, biochemical parameters, and lymphocyte proliferation were assessed. On day 28, the postvaccination antibody titer was determined. The determination of pre- and postvaccination antibody titers against the various influenza antigens was carried out by the hemagglutination inhibition test. An increase of 4x for any of the virus antigens was considered as a seroconversion. A titer higher than 40 at the prevaccination period was considered as protective. RESULTS Eleven elderly subjects were responsive and 12 were not. We have shown that the nutritional parameters such as hemoglobin, hematocrit, total protein, iron and vitamin E levels, as well as the DHEA level and the cellular immune response were significantly lower in the nonresponsive group as compared to the responsive group. Thus, they might be associated with the influenza vaccine responsiveness of institutionalized elderly subjects. CONCLUSIONS These results will help design intervention studies for improving the immune response by achieving an optimal nutritional status, mainly in the frail elderly population, that could have a great public health impact.