Effect of a complete nutritional supplement on antibody response to influenza vaccine in elderly people

Background. The impact of influenza infection on morbidity and mortality in the elderly population can be severe. Influenza vaccination is not very effective in this age group, which is potentially related to impaired nutritional status. We investigated the effect of a 7-month nutritional supplementation on antibody response to influenza vaccine in elderly people. Methods. Nineteen subjects aged 65 years and older with a body mass index of 25 kg/m(2) or less were studied. Subjects received a complete liquid nutrition supplement containing energy, vitamins, and minerals, including enhanced levels of antioxidants or noncaloric placebo drink for 7 months. Antibody titers to influenza strains. A/Sydney/5/97 (SY), A/Beijing/262/95 (BE), and B/Yamanashi/166/98 (YA) before and 28 days after vaccination were measured. Age. gender, weight, height. serum albumin, serum prealbumin, hemoglobin, and serum vitamin E at baseline were registered. Results. Mean fold increase upon vaccination for SY was significantly larger in the supplement group (2.76 +/- 0.66) compared to the placebo group (0.91 +/- 0.66). These differences were not observed for YA (1.73 +/- 0.31 vs 1.19 +/- 0.18) and BE (4.40 +/- 2.63 vs 5.76 +/- 3.34). For all three strains, there was no significant difference between groups in protective antibody levels (HI titer greater than or equal to40) after vaccination. Conclusions. We conclude that provision of a complete liquid nutrition supplement including enhanced levels of antioxidants may have a beneficial effect on antibody response to influenza vaccination in the elderly Population. Further confirmation of these findings and their clinical consequences should be the subject of a larger study.