Back HCV Prevention Injection Drug Use EASL 2015: Reinfection after HCV Cure - Long-term Support Needed for People Who Have Injected Drugs

EASL 2015: Reinfection after HCV Cure - Long-term Support Needed for People Who Have Injected Drugs

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Reinfection rates after a hepatitis C cure among people who inject drugs, as well as past drug users, are relatively low, according to findings from studies from Norway and Canada presented at the European Association for the Study of the Liver (EASL) 50th International Liver Congress in Vienna in April. The findings suggest that current and former injection drug users who have been cured of hepatitis C require ongoing support to remain free of HCV, but also indicate that fears of a high rate of reinfection should not be used as a reason to withhold hepatitis C treatment from people who inject drugs.

[Produced in collaboration with Aidsmap.com]

A meta-analysis of studies of hepatitis C treatment outcomes among people who inject drugs, published in 2013, found an incidence of between 2.4 and 6.4 per 100 person-years of follow-up, but a subsequent meta-analysis found that the reinfection rate could be as high as 8% (Aspinall 2013; Hill 2014).

Further data presented at the International Liver Congress found rates of 3.6 per 100 person-years and 4.6 per 100 person-years among similarly sized cohorts in Montreal and Norway, respectively.

In the Norwegian study, Håvard Midgard from the University of Oslo and colleagues found that people who inject drugs were at high risk of reinfection during a 7-year follow-up period, in large part due to the frequent resumption of injection drug use after a hepatitis C cure.

In contrast, in a study of people with a high risk of hepatitis C virus (HCV) reinfection carried out in Montreal, Nima Machouf and colleagues found a somewhat lower incidence of reinfection among people cured of hepatitis C, but the study also noted a significant association between reinfection and resumption of injection drug use -- often after long periods off drugs.

The Norwegian study investigated the frequency of reinfection in a national cohort of people treated for hepatitis C with pegylated interferon and ribavirin in the NORTH-C trial in 2004, who had achieved a cure (SVR24). 161 patients were cured, of whom 138 were available for follow up, the remainder having either died or been lost to follow up.

Of these, 94 had been injection drug users prior to treatment, while the remaining 44 had not. After a median of 7 years post-treatment, 37% of those who had injected drugs prior to hepatitis C treatment had resumed injecting drugs, and of these, 49% were injecting drugs frequently (reporting a minimum of 100 injections). 13% of all people who had resumed injection drug use had become reinfected with HCV (a total of 12 infections). The rate of reinfection was 1.2 per 100 person-years of follow-up overall, 1.8 per 100 person-years among people who had ever injected drugs, and 4.7 per 100 person-years among those who resumed injecting drug use after achieving a cure.

Lower educational level (secondary school education) and age below 40 were identified as risk factors for reinfection in multivariate analysis.

The Montreal study looked at 338 people cured of hepatitis C at a single clinic in Montreal through the end of 2013 (the HEPVIRAC cohort). Montreal has a high incidence of HCV infection among people who inject drugs (26 per 100 person-years). Researchers wanted to find out whether the reinfection rate was higher among people who inject drugs, and whether particular risk factors for reinfection could be identified in this population. Participants in the cohort study were tested once a year for HCV RNA after being cured, and the date of reinfection was estimated as the midpoint between the last negative test and the first positive test.

Of the 338 cured patients, 82% had been exposed to HCV through injection drug use. 22 members of the cohort became reinfected with HCV after being cured during a median of 2.7 person-years of follow-up, an overall reinfection rate of 1.7 per 100 person-years. The reinfection rate among active injection drug users was 3.6 per 100 person-years.

The study found a median time to reinfection of 14.7 years, suggesting that long-term support for safer injecting practices will be needed for people cured of hepatitis C, as well as support for sustained recovery from drug use for people who stop using drugs, in order to maximize the avoidance of HCV reinfection. 15 of 22 reinfections took place among people considered by researchers to have been "in remission" from active injection drug use, and remission was significantly associated with reinfection when compared to active drug use. The proportion of previous drug users who resumed injection drug use during the follow-up period was not reported.

Two other factors were significantly associated with reinfection: lack of stable housing and HIV/HCV coinfection. Male gender and active injection drug use showed a trend towards association, but these failed to reach statistical significance.

Neither study reported on use of opioid substitution therapy or uptake of harm reduction measures such as sterile needle distribution among cohort participants, both of which might be expected to have an influence on injecting behaviors and the subsequent risk of HCV reinfection. Future studies of well-characterized cohorts could provide valuable operational evidence by looking at these factors.

6/10/15

References

N Machouf, B Trottier, C Galanakis, et al. Low incidence of reinfection with hepatitis C virus after successful treatment in Montreal/Sustainability of HCV cure in a population with a high risk of reinfection: Montreal’s experience. 2015 International Liver Congress: 50th Annual Meeting of the European Association for the Study of the Liver (EASL). Vienna, April 22-26, 2015. Abstract P1250.

H Midgard, B Bjøro, O Dalgard, et al. Incidence of hepatitis C reinfection following sustained virologic response -- a seven year follow-up of Scandinavian patients infected through injecting drug use. 50th Annual Meeting of the European Association for the Study of the Liver (EASL). Vienna, April 22-26, 2015. Abstract O061.