The epidemiology of hepatitis b virus infection in Uganda after two decades of vaccination : a meta-analysis and metaregression

Abstract

Introduction: Hepatitis B virus (HBV) remains a public health threat in Uganda, despite the introduction of the HBV vaccine and its inclusion in the Expanded Program on Immunization (EPI) more than two decades ago. This study aimed at providing up-to-date information on the epidemiology of HBV in Uganda and inform the way forward when designing the interventions to control and prevent the virus. Methods: A systematic search for records published between 1st January 2002 and 30th June 2024 from PubMed and African Journal Online (AJOL) was done from which data on the overall and subgroup prevalence of HBV was extracted. Both the random and fixed effect models were used to pool data for the overall and sub group metaanalysis. The overall and subgroup trend of HBV prevalence over the last two decades was evaluated by metaregression modelling. The predictors of HBV infection were analysed by using odds ratio (OR). The I2 index in the primary records was used to evaluate the heterogeneity. Publication bias in the primary studies was assessed by using Egger’s test and funnel plot asymmetry. All analyses were done at 95% confidence interval (CI) and a p < 0.05 was considered significant. Results: A total of 34 original studies were included in the data synthesis with a pooled sample size of 81,416 individuals. The pooled prevalence of HBV was 8.3% but varied with region and study group. It was highest in the eastern region (p < 0.05) and among the community-based studies (p < 0.05). By meta-regression modelling, there has been an overall decrease in the prevalence of HBV since the integration of the vaccine as part of the EPI in 2002 (p < 0.05) and in the central, eastern and northern regions. Conversely, there was an increase in the prevalence of HBV in western Uganda with a strong temporal explanatory power (R² = 0.700). Familial contact with an HBV infected person; odds ratio (OR) = 3.85, p = 0.006 was the most significant risk factor for HBV infection. In contrast, age < 20 year; OR = 0.52, p = 0.016 was protective against HBV infection. Conclusion: Despite the significant progress registered in reducing the prevalence of HBV since the integration of HepB vaccine as part of the EPI, there are still regional and cohort specific disparities in the prevalence of HBV in Uganda. Thus, different interventions should be designed in tandem with the differences in the prevalence by specific groups and regions.