Cross-sectional study of chronic hepatitis B virus infection in Rwandan high-risk groups: unexpected findings on prevalence and its determinants

Objectives Using secondary data from 208 079 Rwandans, we determined the prevalence of chronic hepatitis B virus (HBV) infection among high-risk groups and its demographic, geographical and health-related determinants. Design In this cross-sectional study, we obtained and analysed data from a national hepatitis B vaccination and screening campaign conducted in Rwanda in 2017. We performed logistic regression to examine associations between chronic HBV infection and related factors such as risk status and geographical characteristics. Setting Individuals were sampled nationally in all 30 districts across 4 provinces and the city of Kigali and all prisons in Rwanda. Participants The study involves 208 079 individuals at high risk including prisoners and other high-risk groups (oHRG). Main outcome The primary outcome for our study was hepatitis B surface antigens (HBsAg) prevalence. Findings From 208 079 adults participants, 206 517 (99.2%) had valid HBsAg results, 4.3% of 64 944 prisoners and 4.0% of 140 985 oHRG were HBV positive. The prevalence was higher in Northern Province 5.1%, (95% CI 4.8 to 5.4). In multivariate analysis, the odds of infection decreased with increasing age, and hepatitis C antibody positivity reduced the odds for chronic HBV (OR 0.58, 95% CI 0.52 to 0.66 and OR 0.74, 95% CI 0.62 to 0.89 among oHRG and prisoners, respectively). In addition, being female was associated with lower odds of HBV (OR 0.70, 95% CI 0.66 to 0.74 and OR 0.80, 95% CI 0.65 to 0.98 among oHRG and prisoners, respectively). Conclusion We found that individuals below 55 years of age and individuals who belong to high-risk groups (ie, sex workers, injection drug users, men who have sex with men, etc) have a higher probability of chronic HBV infection. Infection with chronic hepatitis C virus was not correlated with chronic HBV infection in our study population. Potential explanations include differential routes of transmission, specific immunological and pathophysiological factors or different effects of health prevention and control programmes.