Imported dengue fever in South Korea, 2020-2024: Epidemiological trends and serotype distribution from national...

South Korea remains at risk for dengue virus (DENV) importation, primarily due to the widespread presence of Aedes albopictus and increasing international travel. This study investigated diagnostic trends, serotype distribution, and geographic origins of imported dengue cases in South Korea from 2020 to 2024.

Laboratory-confirmed dengue cases reported from January 2020 to December 2024 were retrospectively analyzed using data from public institutions and selected private laboratories. Diagnostic confirmation utilized IgM ELISA and RT-PCR. Serotyping of DENV-1-4 was performed in public institutions. Travel history information aided the analysis of temporal and geographic trends. Fisher's exact test was used for statistical evaluation.

A total of 551 dengue cases were confirmed, with only one nosocomial infection and no local vector-borne transmission. Public laboratories identified most cases (89.1 %). RT-PCR confirmed 279 (50.6 %) and IgM ELISA 270 (49.0 %) cases. Serotype analysis of 221 cases detected all four DENV serotypes, with DENV-1 and DENV-2 predominant. Most exposures occurred in Vietnam, Indonesia, the Philippines, and Thailand, highlighting key importation sources.

Nationwide public laboratory surveillance is vital for timely detection and characterization of imported dengue. These findings underscore the influence of international travel and the need for sustained vector monitoring, vaccine preparedness where appropriate, and traveler-targeted prevention in non-endemic regions.