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Importation-Driven Measles Resurgence and the Fragility of Elimination, Japan, 2024–2026

Year: 2026

Type: review

Abstract: As measles elimination unravels across the Americas, Europe, and the Western Pacific, Japan is experiencing a resurgence of measles; the World Health Organization had verified elimination of measles in Japan in 2015. By epidemiologic week 20 of 2026, a total of 498 cases had been reported, exceeding every full-year total since 2020. Median case-patient age has fallen to 26 years, shifting the burden from a generation who received single-dose measles vaccinations to younger cohorts caught between successive vaccination-policy transitions. Among case-patients with a documented 2-dose vaccination history, more than half experienced modified measles, an attenuated, easily missed illness that delays diagnosis and isolation. As mass gatherings concentrate global travel, Japan has become a sentinel for the fragility of measles elimination, including in countries that consider elimination status secure. Surveillance shows importation-driven resurgence; the shift in genotype profile from D8 to B3 predominance back to D8 enabled tracking of source countries.

Source: Emerging infectious diseases

DOI: 10.3201/eid3211.261187

Authors: Koichiro Yuji, Wakako Yuji, Eisuke Adachi

Institutions: Kitasato Institute Hospital, Institute of Medical Science, The University of Tokyo, The University of Tokyo

Language: English

Topic: Virology and Viral Diseases

Subfield: Epidemiology

Field: Medicine

Domain: Health Sciences

SDG: Good health and well-being

Open Access status: diamond

OpenAlex ID: W7214713227

FWCI:

Cites: 17

Cited by:

Related to: 10