Prevalence and factors associated with hepatitis B and D virus infections among migrant sex workers in Chiangmai, Thailand : a cross-sectional study in 2019 Hongjaisee, S. Khamduang, W. Sripan, P. Choyrum, S. Thepbundit, V. /Ngo-Giang-Huong, Nicole Tangmunkongvorakul, A. Migrants Sex workers HBV HDV Prevalence Thailand Objectives: To determine the prevalence of hepatitis B surface antigen (HBsAg) and antibody to hepatitis delta virus (anti-HDV) and associated factors among migrant sex workers in Chiangmai, Thailand. Methods: This cross-sectional study was conducted at various sexual entertainment venues in Chiangmai, Thailand, in 2019. Consenting participants were interviewed using a questionnaire, and plasma was tested for hepatitis B virus (HBV) markers (DiaSorin, Italy) and anti-HDV antibody (DIA.PRO Diagnostic Bioprobes, Italy), if HBsAg-positive. Associations between HBsAg positivity or HDV antibody and potential factors were examined using univariable and multivariable logistic regression analysis. Results: A total of 396 migrant sex workers, half of them female, were recruited between February and September 2019. Their median age was 25 years (interquartile range 22-30 years) and 95% were Burmese. Overall, HBsAg prevalence was 11.4%; 8.1% in females and 14.7% in males (Chi-square, p = 0.040). One-third were still susceptible to HBV. No HBsAg-positive participants had anti-HDV antibodies. HBsAg positivity was associated with being male (adjusted odds ratio (aOR) 3.01, 95% confidence interval (CI) 1.25-7.68, p = 0.014), having attended school (aOR 4.50, 95% CI 1.26-15.98, p = 0.020), being separated/divorced/widowed (aOR 5.77, 95% CI 1.48-22.52, p = 0.012), and having unprotected sex (aOR 3.38, 95% CI 1.31-8.71, p = 0.012). Conclusions: In this young population, higher HBsAg prevalence in males may be related to sexual transmission, indicating the need for HBV screening programs linked with HBV prevention and care. 2020 text https://www.documentation.ird.fr/hor/fdi:010080898 fdi:010080898 Hongjaisee S., Khamduang W., Sripan P., Choyrum S., Thepbundit V., Ngo-Giang-Huong Nicole, Tangmunkongvorakul A.. Prevalence and factors associated with hepatitis B and D virus infections among migrant sex workers in Chiangmai, Thailand : a cross-sectional study in 2019. 2020, 100, 247-254 EN THAILANDE CHIANG MAI