17dd yellow fever revaccination and heightened long-term immunity in populations of disease-endemic areas, brazil

Abstract

We evaluated the duration of neutralizing antibodies and the status of 17DD vaccine–specific T- and B-cell memory following primary and revaccination regimens for yellow fever (YF) in Brazil. We observed progressive decline of plaquereduction neutralization test (PRNT) seropositivity and of the levels of effector memory CD4+ and CD8+ T cells, as well as interferon-γ+CD8+ T cells, 10 years after primary vaccination. Revaccination restored PRNT seropositivity as well as the levels of effector memory CD4+, CD8+, and interferon- γ+CD8+ T cells. Moreover, secondary or multiple vaccinations guarantee long-term persistence of PRNT positivity and cell-mediated memory 10 years after booster vaccination.