Evaluation of Cell-mediated Immunity and Antibody Response to Influenza Vaccination and Correlates of Protection in Seniors

During the 2010-2011 influenza season, approximately 100 adults ≥65 years of age will be enrolled. After consent, blood and serum will be collected and then subjects will be randomized to either standard or high dose influenza vaccine (both FDA approved vaccines). Vaccination will be done by an unblinded nurse. All further evaluations and analysis will be done by a blinded staff member. Medical history, relevant medications, and functional/nutritional status will be assessed at the first visit. Subjects will return (Table 3) for blood and serum draws on days 7, 14, 28 and for a serum blood draw after influenza season. No micronutrient samples will be drawn, but serum will be kept for possible vitamin D testing. During influenza season, subjects will answer a questionnaire about influenza-like illness (ILI) every two weeks (either by email or telephone) and will be asked to return for a nasal swab if an ILI is present. Comparisons will be made of the cell-mediated response of those vaccinated with standard versus high dose vaccines. Analyses will be done accounting for age, use of immunomodulating agents, and underlying medical conditions.