Spatial Heterogeneity and Correlates of Reported Mpox Incidence in Thailand: Implications for Targeted Surveillance and Control

Mpox emerged as a global public health concern following the 2022 multi-country outbreak, and reported cases in Thailand varied markedly across provinces. This cross-sectional ecological study examined the spatial distribution of reported mpox incidence and its provincial-level correlates. Surveillance data for 2023 were analysed for all 77 provinces, with expected counts obtained by indirect standardisation on provincial population. A Bayesian hierarchical spatial model was implemented using the integrated nested Laplace approximation (INLA). Observed counts of mpox cases were modelled using a zero-inflated Poisson likelihood. Covariates were standardised, and results are reported as relative risk (RR) per standard deviation. Reported incidence was highly concentrated: four provinces were classified as high-risk areas. Night-time light intensity (RR 1.83, 95% credible interval 1.14–2.97) and gonorrhoea notification rate (1.70, 1.16–2.49) were positively associated with reported incidence. The night-time light association persisted in all sensitivity analyses, whereas the gonorrhoea association was attenuated after adjustment for health-facility density and when cases were assigned by province of onset. Mpox associations with tourism, population density, education, male age structure and poverty were not statistically significant. These are provincial-level associations, not individual-level risks or transmission mechanisms. Sexually transmitted infection notification rates, considered together with diagnostic capacity, may help to indicate where mpox surveillance should be strengthened.