Serological surveillance for malaria elimination in Southeast Asia: a scoping review.

BACKGROUND: As Southeast Asian countries advance toward malaria elimination, challenges such as residual transmission reservoirs and zoonotic spill-over require high-resolution micro-surveillance. While conventional diagnostics often miss hidden transmission foci in low transmission settings, serological assays provide an essential supplement by measuring both historical and recent exposure. This scoping review assesses the implementation of antibody surveillance across Southeast Asian countries and highlights its potential in the concerted effort towards regional malaria elimination. METHODS: This review adhered to the PRISMA-ScR guidelines to identify peer-reviewed studies on malaria serology in Southeast Asian countries. Systematic searches of PubMed, Web of Science and Scopus were conducted for articles published between January 2000 and May 2025. Multiple independent reviewers screened titles, abstracts and full texts against predefined eligibility criteria, focusing on English-language primary studies involving human samples. Extracted data including study location, population, serological assay type, serological markers and key findings were synthesised to provide a comprehensive overview of malaria antibody surveillance. RESULTS: Of 6,849 records identified, 33 studies across seven Southeast Asian countries met the inclusion criteria. Study designs consisted of 26 cross-sectional, five longitudinal and one each of a prospective cohort and a control trial. Over time, research focuses have shifted from high-transmission assessments to low-transmission and elimination contexts, increasingly utilising multiplex assays and protein microarrays. While Plasmodium falciparum and Plasmodium vivax markers predominated, recent studies have incorporated Plasmodium knowlesi and vector exposure antigens. Furthermore, seroconversion rate estimation and machine learning approaches effectively identified historical transmission declines and residual hotspots missed by conventional microscopy or molecular methods. CONCLUSION: Serological surveillance offers a transformative supplement to the diagnostic gaps prevalent in Southeast Asia's low-transmission settings. By generating a high-resolution exposure profile, advanced seroepidemiological tools enable precise micro-stratification of transmission foci, the differentiation of recent from historical exposure and the targeted management of zoonotic spill-over. Ultimately, integrating these methods provides a robust, cost-effective framework for identifying high-risk populations, verifying transmission interruption and achieving regional malaria-free certification.