An outbreak of Japanese encephalitis in Southeast Asia: A meta-analysis

Japanese encephalitis (JE) remains a major vector-borne
neurological disease across Asia and the Western Pacific, with
substantial morbidity and mortality, despite the availability of
effective vaccines. This meta-analysis synthesized
seroprevalence data from Southeast Asia to provide an
updated regional estimate and identify key demographic and
environmental risk factors. Following PRISMA guidelines,
eight eligible studies published between 2001 and 2024 were
analyzed. The pooled seroprevalence of Japanese encephalitis
virus (JEV) was 37.11%, with wide geographical variability
across countries. Diagnostic methods included ELISA
(IgM/IgG), neutralization assays, and hemagglutination
inhibition tests. Risk factor assessment showed no significant
differences between young and adult or adult vs. elderly
populations. In contrast, gender- and location-based
variations were observed: males showed a modestly higher
risk in some models, and rural populations exhibited a 35%
higher likelihood of seropositivity than urban communities.
These findings highlight persistent JE transmission in high
risk areas and support the need for strengthened vaccination
coverage, enhanced vector management, and improved
diagnostic capacity, particularly in rural settings. Continued
surveillance and targeted public health strategies are
essential to reduce the burden of JE and to guide future
vaccine implementation efforts in Southeast Asia.

KEYWORDS
Demographic risk factors; Japanese encephalitis; Japanese
encephalitis seroprevalence; meta-analysis; Southeast Asia;
vector-borne disease.