Taiwan's Strategy Toward Measles Elimination

Sustaining measles elimination in the post-elimination era presents increasing challenges due to global resurgence and waning vaccine-induced immunity. We aimed to evaluate epidemiological trends, vaccination strategies, and population immunity associated with achieving and maintaining measles elimination in Taiwan.

We conducted a comprehensive analysis of national surveillance data from 1991 to 2024, including case notifications, viral genotypes, vaccination coverage rates, and surveillance performance indicators. Three population-based seroprevalence surveys conducted between 2002 and 2020 were reviewed to assess age-specific immunity. Descriptive analyses were performed to characterize long-term epidemiological and immunological trends.

From 1993 to 2024, the annual number of measles cases remained consistently below 50, except in 2019. Vaccination coverage for both MMR1 and MMR2 has exceeded 95% since 1998, with MMR1 coverage remaining above 97% between 2009 and 2024. Genotyping evidence confirms the interruption of endemic transmission since 2006; furthermore, as of 2024, no continuous chains of transmission lasting longer than 12 months have been recorded. National seroprevalence surveys monitoring measles-specific IgG antibodies revealed declining antibody levels among adolescents and young adults, with seropositivity as low as 36.7% in specific cohorts. Despite this, transmission following importations has remained limited, with minimal secondary spread.

Taiwan has successfully sustained measles elimination through high vaccination coverage, robust surveillance, and targeted interventions. Although serological evidence indicates waning immunity, epidemiological data suggest preserved population-level protection, likely mediated by immunological memory. Targeted booster strategies for high-risk groups may be more appropriate than universal additional dosing in post-elimination settings.