Background: Advanced age is accompanied by a decline of immune functions, which may play a role in increased vulnerability to emerging pathogens and low efficacy of primary vaccinations in elderly people. The capacity to mount immune responses against new antigens is particularly affected in this population. However, its precise determinants are not fully understood. We aimed here at establishing the influence of persistent viral infections on the naive T-cell compartment and primary immune responsiveness in older adults. Methods: We assessed immunological parameters, related to CD8+ and CD4+ T-cell responsiveness, according to the serological status for common latent herpesviruses in two independent cohorts: 1) healthy individuals aged 19y to 95y. Findings: We demonstrate a prevalent effect of age and CMV infection on CD8 T-cell and antibody responses to primary vaccination. Interpretation: These data provide insights on the changes in adaptive immunity over time and the associated decline in vaccine efficacy with ageing. This knowledge is important for the management of emerging infectious diseases in elderly populations.
Volume 76, February 2022, 103852