Injecting drug users' self-reported understanding of their blood borne virus status – how reliable is it? A study of drug users in North London, UK

Setting: 220 drug users from a specialised general practice providing primary care to drug users in North London, UK.

Methods: Patients' self-reported hepatitis B, C and HIV status and hepatitis B vaccination history were collected for the 220 most recent registrations at the unit. Patients' reported status was compared with contemporaneous serology results to assess patients' accuracy of knowledge.

Results: Most participants were male, white and between 31 and 40 years, 75% were current injecting poly-drug users. Serological results showed the following prevalence; Hepatitis C 50.9%, Hepatitis B 33.6% and HIV 5.5%. Accuracy of knowledge varied between the viruses. 52.3% of participants were accurate about their HIV status; 47.7% and 30.0% were correct in their knowledge of their hepatitis C and B infection status respectively. Only 13.6% of participants reported having previously received a full course of hepatitis B vaccine, while 49% reported having received no vaccine.

Conclusions: Participants were often inaccurate in their knowledge of their blood borne virus infection status with only one third accurately reporting their HBV status. 13.6% of participants reported having a full course of hepatitis B immunisation; this is worryingly low given the high prevalence of HBV infection. Poor uptake of HBV vaccine may well be related to drug users' inaccurate knowledge of their infection status with respect to blood borne viruses. Self – reporting does not appear to be a reliable means of assessing the prevalence of such viruses in drug users and should probably be disregarded when considering offering screening or HBV vaccination.