Prevalence of hepatitis B, tetanus, hepatitis A, human immunodeficiency virus and feasibility of vaccine delivery among injecting drug users in Bangkok, Thailand, 2003-2005.

Objectives To estimate the prevalence of hepatitis B virus (HBV), tetanus, hepatitis A virus (HAV) and human immunodeficiency virus (HIV) in injecting drug users (IDUs), risk factors associated with infection and the feasibility of HBV vaccine delivery in HBV seronegatives. Methods Cross-sectional seroprevalence survey of 1535 IDUs recruited from 17 Bangkok Metropolitan Administration (BMA) methadone clinics and HBV vaccination of seronegatives. Results Prevalence of antibody to HBV, tetanus, HAV and HIV was 87.8%, 68.1%, 60.2% and 35.9%, respectively. Prevalence of HBV and HAV increased with increasing age; prevalence of tetanus decreased with increasing age. Being HIV seropositive was related inversely to income and being tetanus seronegative. Of the 189 HBV seronegative IDUs, 81.0% completed the vaccine series. IDUs with HIV had a 6.5-fold odds of vaccine non-response. Conclusions These data underscore the need for, and feasibility of, vaccine delivery in this population and support targeting efforts at high-risk age groups.