Why do flu shots weaken with age? new study aims to find out

This study follows 75 adults aged 65 and older over three to four flu seasons to learn why the flu vaccine becomes less effective as people age. Participants will receive a different FDA-approved flu vaccine each year, and researchers will collect blood, nasal swab, and stool samples to measure immune responses. The goal is to understand the biological changes behind reduced vaccine response, not to test safety or effectiveness of the vaccines.