Hepatitis B virus among injecting drug users in Sydney, Australia: prevalence, vaccination and knowledge of status.

Abstract

Despite the availability of an inexpensive and safe vaccine, injecting drug users (IDUs) remain at risk of hepatitis B virus (HBV) infection. This paper aimed to measure HBV prevalence and vaccination coverage and to assess knowledge and concordance of status among IDUs. Participants were recruited through a primary health care and a drug treatment service and via street press in Sydney, Australia. Face-to-face interviews were conducted and serology collected. All received $30 for participation. 229 participants were recruited, serology was available for 209. Almost all those interviewed had been tested for HBV (95%) a median of four (IQR 2-10) times and 61% had been tested in the preceding year. Fifty-four percent had evidence of previous infection (anti-HBc) and 5% were HBsAg positive. Only 27% had serological evidence of vaccination immunity; however, 43% of the sample recalled having being told by a health professional that they were vaccinated against HBV. Although only three participants reported they did not understand the results of their last HBV test, confusion was evident based on self-reported status. Levels of understanding and vaccination coverage were low while evidence of prior infection was high among this IDU sample. This is cause for concern given the majority of participants were recruited through primary care and treatment services. Strategies to bolster vaccination among this group will be discussed.