Hepatitis D virus infections among injecting drug users with and without human immunodeficiency virus infection in Taiwan

In Taiwan, injecting drug use has been the main route of human immunodeficiency virus (HIV) transmission since 2005, with hepatitis B virus (HBV) and hepatitis D virus (HDV) also having similar transmission routes. This has now become an important public health issue. The aim of this study is to explore the conditions of HDV infections between injecting drug users (IDUs) with and without HIV infection in Southern Taiwan. In this study, 87 IDUs were enrolled, including 27 anti-HDV seronegative IDUs and 60 anti-HDV seropositive IDUs, and the results of their liver function tests, CD4 cell counts, and anti-HIV and HIV RNA levels were analyzed. The prevalence of anti-HDV seropositivity among hepatitis B surface antigen (HBsAg) seropositive IDUs in this study was 68.9% (60/87). The prevalence rate of anti-HDV seropositive IDUs among anti-HIV seronegative and anti-HIV seropositive cases was 40.0% (12/30) and 84.2% (48/57), respectively. Anti-HIV seropositivity was related to anti-HDV seropositivity (odds ratio = 9.34, 95% confidence interval = 2.67-31.59, p < 0.001). Among IDUs with HIV infection, there was no significant difference in CD4 cell counts and HIV RNA viral load between HBsAg-positive patients with anti-HDV seronegativity and those with anti-HDV seropositivity. In conclusion, the prevalence of HDV infection among IDUs is higher among IDUs with HIV infection. Because anti-HIV seropositivity is significantly related to anti-HDV seropositivity, HDV infection among IDUs is still important. We suggest that for IDUs, HBsAg and anti-HDV should be monitored closely.