Vaccine response in aging

Vaccines work less well as you age, and several immune changes pile up to cause it. You have fewer fresh (naive) T and B cells, weaker germinal-center reactions, shorter-lived antibody factories (plasma cells), and a jumpier innate immune system. Together these lower how strong, precise, and lasting your vaccine protection is. So vaccines for older adults are often reformulated to push harder. High-dose or adjuvanted flu shots (like Fluzone High-Dose, or Fluad with the MF59 adjuvant) raise protection rates well above standard shots in people over 65. The shingles vaccine Shingrix, which uses the AS01B adjuvant to drive a strong T-cell and antibody response, is about 90 to 97% effective depending on age (around 91% in adults 70+, from the pooled ZOE-50/ZOE-70 analysis). Compare that to roughly 50% for the older live Zostavax, which the US dropped in 2020. It is a clear example of how clever adjuvants can partly make up for age-related immune decline (immunosenescence).

Last reviewed: June 22, 2026

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