Factors associated with hepatitis A virus infection among HIV-positive patients before and after implementation of a hepatitis A virus vaccination program at a medical centre in central Taiwan

Background: Taiwan government has promoted the administration of a hepatitis A vaccine at public expense for high-risk groups as a preventive measure after the outbreak of hepatitis A virus (HAV) infections in 2015. The aim of this study was to evaluate the efficacy of such vaccination policy in patients with human immunodeficiency virus (HIV). Methods: From January 2016 to July 2017, we enrolled 658 HIV-positive male participants. Participants were stratified into anti-HAV-positive (n = 165) and anti-HAV-negative (n = 493) groups. A total of 364 anti-HAV-negative patients received vaccination against HAV and were followed up for 1.5 years. A Cox regression model was used to estimate the effects of factors predicting positive anti-HAV detection after vaccination. Results: Patients with HIV had an anti-HAV-positive prevalence of 25.1% before vaccination. Of the 364 patients inoculated with the first dose of vaccine, 58.0% received the second dose. Seroresponse rates were 50.0% and 80.6%, respectively. Antibody production was 30.0% lower in patients with a CD4 T-cell count <200 cells/µL (adjusted relative risk (ARR) = 0.7 95% confidence interval (CI) = 0.5-0.9) compared with those with 500 cells/µL. Hepatitis C co-infection reduced the production of antibodies by 50.0% (ARR = 0.5 95% CI = 0.2-0.8). Conclusion: This study suggests that vaccination against hepatitis A be administered when the immunity of an HIV-positive patient is strong. The promotion of the current vaccination policy against hepatitis A in Taiwan has improved the vaccination rate the response rate for receiving one dose of the vaccine doubled.