A Deep Longitudinal Analysis of Next Generation Influenza Vaccines in Older Adults

This is a prospective, single-arm study designed to understand the mechanisms that lead to a loss of response to influenza vaccine in older adults. The investigators will recruit and longitudinally follow a cohort of 75 older adults (65 years and older) who will receive three different influenza vaccines over three annual influenza seasons. Blood samples will be collected from the participants at sixteen study visits over three years. Nasal swab and stool samples will also be collected from participants at seven time-points across the study period. After completion of study visits other than the End of Study visit around vaccination in Year 3, participants will be offered the opportunity to be vaccinated with a different FDA approved influenza vaccine and participate in study visits for Year 4. The study is not designed to assess safety or tolerability of the influenza vaccines administered as part of this study.