Assessment of seroprevalence of Mpox virus infection among sex workers in Chiang Mai, Thailand.

OBJECTIVES

The 2022 global Mpox outbreak revealed major surveillance gaps, particularly among marginalized populations such as sex workers, whose role in undetected MPXV transmission remains poorly understood. This study aims to assess the seroprevalence of MPXV IgG antibodies and identify associated risk factors among sex workers in Chiang Mai, Thailand.

METHODS

In this cross-sectional study, 262 sex workers recruited from March to December 2022 were tested for prior MPXV exposure using an in-house indirect ELISA targeting the recombinant MPXV E8L antigen. Logistic regression models were used to identify demographic and behavioral factors associated with seropositivity.

RESULTS

MPXV IgG seroprevalence was 4.6% (12/262). Seropositivity was significantly higher among males than females (5.2% vs 4.0%, P = 0.011). In multivariable analysis, male gender (OR = 3.23, 95% CI: 1.10-9.47, P = 0.032), blood transfusion history (OR = 4.40, 95% CI: 1.35-14.25, P = 0.013) and sharing sharp objects with others (OR = 4.55, 95% CI: 1.12-18.48, P = 0.034) were significantly associated with Mpox seropositivity.

CONCLUSION

Our findings reveal undetected MPXV circulation among Chiang Mai sex workers. The identified risk factors suggest overlapping parenteral and sexual vulnerabilities, emphasizing the need for integrated surveillance and targeted interventions.