Hepatitis B Virus Exposure, Seroprotection Status, and Susceptibility in Health Care Workers From Lao People's Democratic Republic: Cross-Sectional Study.

Background: Despite the high prevalence of chronic hepatitis B virus (HBV) infection in adults in Lao People's Democratic Republic (Lao PDR), Lao health care workers (HCWs) have previously been shown to have low levels of protection against infection. Furthermore, the prevalence of hepatitis D virus (HDV), which increases disease severity in individuals infected with HBV, is not known in Lao PDR. Objective: This study aimed to estimate the exposure and seroprotection against HBV, as well as exposure to HDV, in Lao HCWs from 5 provinces. Methods: In 2020, a total of 666 HCWs aged 20 to 65 years from 5 provinces of Lao PDR were recruited, and their sera were tested by enzyme-linked immunosorbent assay to determine their HBV and HDV coinfection status. Results: HBV exposure, as indicated by the presence of anti-hepatitis B core antibodies, was 40.1% (267/666) overall and significantly higher for HCWs from Oudomxay province (21/31, 67.7%; adjusted odds ratio 3.69, 95% CI 1.68-8.12; P=.001). The prevalence of hepatitis B surface antigen was 5.4% (36/666) overall and increased with age, from 3.6% (9/248) in those aged ≤30 years to 6.8% (8/118) in those aged ≥50 years. Only 28.7% (191/666) of participants had serological indication of immunization. We could find no evidence for HDV exposure in this study. Conclusions: The study found intermediate hepatitis B surface antigen prevalence among HCWs in Lao PDR, with no evidence of HDV coinfection. Notably, a significant proportion of HCWs remains susceptible to HBV, indicating a substantial gap in seroprotection against the disease.