Waning Measles Immunity and Sustained Rubella Seroprotection Among Adults in Istanbul, Türkiye
A significant measles immunity gap exists among younger adults in Türkiye, with Measles IgG seropositivity declining from 78.4% in 2014–2019 to 62.6% in 2022, consistent with a cohort effect whereby vaccine-era cohorts exhibit lower protection than older adults with naturally acquired immunity.