hepatitis C virus (HCV) is associated with a sustained reduction in injecting
drug use, according to Canadian research published in the online edition of Clinical Infectious Diseases. Each
additional three months of follow-up was associated with a 10% reduction in the
likelihood of injecting cocaine or heroin. Screening for HCV was also associated with a
reduction in the likelihood of sharing syringes, not only for people
diagnosed with HCV but also for individuals testing HCV negative.
“The main finding
of this study is that notification of HCV test results and counseling is
related to reductions in subsequent drug use behavior for PWIDs [people who inject
drugs] learning that they recently contracted an HCV infection, but not for
those who are uninfected,” comment the authors. “Reductions in drug use
behaviors are likely to reflect a response to being informed about a recent
The authors of an
editorial that accompanies the study believe the results highlight “the
importance of HCV testing as a catalyst for behavior change”.
injecting drug use is the main mode of HCV transmission. Canada is a case in
point, where 83% of incident infections involve PWIDs. Harm-reduction
programmes that provide access to clean needles and syringes, information about
safer injecting practices, and screening for HCV and HIV, are the mainstay of
HCV prevention in Canada and some other countries.
Montreal wanted to see if testing for HCV had a sustained impact on injecting
behaviours and alcohol use among PWIDs.
designed a longitudinal study involving 208 adults who were active injecting
drug users and who were HCV negative at baseline. Every six months, participants
were screened for HCV and answered questions about their recent injecting
behaviours and use of alcohol. Post-test counselling and appropriate referrals
The majority of
participants were male (83%), and their mean age was 34 years. The mean duration
of follow-up was 30 months. During this time, participants contributed a total
of 528 person-years of follow-up. A third of participants seroconverted for HCV, an
incidence rate of 14.4 per 100 person-years. Individuals who seroconverted were
significantly more likely than individuals who remained HCV negative to report
injecting opioids (51 vs 22%, p < 0.001), cocaine (87 vs 63%, p = 0.004)
and the sharing of syringes (39 vs 24%, p = 0.021) in the previous six months.
the proportion of participants who reported sharing syringes fell to very low
levels, irrespective of HCV infection status.
Notification of a
positive HCV test result was also associated with significant and sustained
falls in the odds of reporting injecting cocaine or heroin. Each additional three months
of follow-up was associated with a 10% reduction in reporting each of these
injecting behaviours. However, injecting of heroin and cocaine remained
unchanged among participants who tested HCV negative.
suggest that it is mainly the notification of the HCV positive status that
induces the decrease in risk among PWIDs,” write the investigators. “There is
no sustained change in risk among those who continue to be seronegative.”
Regardless of the
result, there was no evidence that HCV screening had an impact on alcohol use.
The authors believe this finding “should raise concern” as alcohol is
associated with accelerated HCV disease progression.
“The change in
injecting behaviors after testing for HCV that was observed in this study
strongly supports the expansion of HCV testing,” write the authors of the
editorial. “Future research is needed to elucidate which interventions or
experiences promote safer or less injection drug use among persons testing
positive for HCV.”