Prevalence and Seroincidence of Hepatitis B and Hepatitis C Infection in High Risk People Who Inject Drugs in China and Thailand

We determined the prevalence and incidence of HBV and HCV infection in people who inject drugs (PWIDs) at high risk for HIV in China and Thailand and determined the association of HBV and HCV incidence with urine opiate test results and with short-term versus long-term buprenorphine-naloxone (B-N) treatment use in a randomized clinical trial (HPTN 058). 13.8% of 1049 PWIDs in China and 13.9% of 201 PWIDs in Thailand were HBsAg positive at baseline. Among HBsAg negative participants, the HBsAg incidence rate was 2.7/100 person years in China and 0/100 person years in Thailand. 81.9% of 1049 PWIDs in China and 59.7% of 201 in Thailand were HCV antibody positive at baseline. The HCV confirmed seroincidence rate among HCV antibody negative PWIDs was 22/100 person years in China and 4.6/100 person years in Thailand. Incident HBsAg was not significantly different in the short-term versus long-term B-N arm in China or Thailand. Participants with positive opiate results in at least 75% of their urines during the time period were at increased risk of incident HBsAg (HR = 5.22; 95% CI, 1.08 to 25.22; ) in China, but not incident HCV conversion in China or Thailand. 1. Background and Objectives Transmission of hepatitis C virus (HCV), hepatitis B virus (HBV), and human immunodeficiency virus (HIV-1) has been causally associated with the injection of drugs of abuse by people who inject drugs (PWIDs) due to sharing of needles and injection equipment contaminated by infected blood. HCV and HBV seroprevalence rates among PWIDs have varied considerably depending on the geographic region and time period of the PWID populations tested. HCV seroprevalence rates among most PWIDs populations worldwide have been reported to be often higher than 50% with widely varying rates of 3–95% for HIV/HCV coinfection [1]. In China, HCV prevalence rates among the general population have been estimated to be approximately 3.2% [2] with HCV prevalence rates of between 34% and 99% among PWID populations [2]. In Thailand, an HCV prevalence rate of 70% among PWIDs has been reported [3]. HCV coinfection complicates HIV treatment options and has been reported to increase the probability of progression to a new AIDS-defining clinical event or to death and is associated with a smaller CD4-cell recovery increase in response to HIV therapy [4]. Hepatitis B surface antigen (HBsAg) prevalence rates in China have been relatively high with an estimated 7.18% rate in the general population in 2006 [5]. In Thailand, the HBsAg prevalence rate among HIV infected Thai patients has been reported to be 8.7%