Seroprevalence of IgG antibodies against measles in adolescents and adults from Metropolitan Lima and Callao, Peru, 2024-2025.

Abstract

Objectives: To estimate the seroprevalence of measles IgG antibodies in people aged 15 years or older residing in Lima Metropolitan and Callao, Peru, through secondary analysis of serum samples obtained from the National Institute of Health's Non-Communicable Diseases Surveillance between 2024 and 2025.

Materials and methods: A descriptive, population-based, cross-sectional study that included 770 serum samples, in which the presence of measles IgG antibodies was determined using a commercial ELISA assay. Global seroprevalence was estimated and stratified by sex, age group, and origin.

Results: After data expansion, 53.6% of the studied population corresponded to women. The global seroprevalence was 82.1% (95% CI: 78.6%-85.1%). Adults aged 20 to 29 years showed the lowest seroprevalence (55.6%), followed by adolescents aged 15 to 19 years (72.0%). Seroprevalence progressively increased with age and exceeded 95% in people aged 50 years or older. No significant differences were observed by sex or area of origin.

Conclusions: Immunity gaps against measles are evident mainly in young adults, in a context of disease resurgence in the Americas and an ongoing outbreak in Peru. These findings highlight the value of seroprevalence studies to identify susceptible groups and guide public health interventions, such as targeted vaccination strategies, strengthening epidemiological surveillance, and information campaigns to reduce immunity gaps and contribute to maintaining measles elimination in Peru.