Hepatitis C reinfection after sustained virological response.
Midgard H.
J Hepatology 2016 ; 64 :1020-6

Abstract: Background & Aims: On-going risk behaviour can lead to hepatitis C virus (HCV) reinfection following successful treatment. We aimed to assess the incidence of persistent HCV reinfection in a population of people who inject drugs (PWID) who had achieved sustained virological response (SVR) seven years earlier.

Methods: In 2004–2006 we conducted a multicentre treatment trial comprising HCV genotype 2 or 3 patients in Sweden, Norway and Denmark (NORTH-C). Six months of abstinence from injecting drug use (IDU) was required before treatment. All Norwegian patients who had obtained SVR (n = 161) were eligible for participation in this long-term follow-up study assessing virological and behavioural characteristics.

Results: Follow-up data were available in 138 of 161 (86%) individuals. Persistent reinfection was identified in 10 of 94 (11%) individuals with a history of IDU prior to treatment (incidence rate 1.7/100 person-years (PY); 95% CI 0.8–3.1) and in 10 of 37 (27%) individuals who had relapsed to IDU after treatment (incidence rate 4.9/100 PY; 95% CI 2.3–8.9). Although relapse to IDU perfectly predicted reinfection, no baseline factor was associated with reinfection. Relapse to IDU was associated with age <30 years (vs. P40 years) at treatment (adjusted odds ratio[aOR] 7.03; 95% CI 1.78–27.8) and low education level (aOR 3.64; 95% CI 1.44–9.18).

Conclusions: Over time, persistent HCV reinfection was common among individuals who had relapsed to IDU after treatment. Reinfection should be systematically addressed and prevented when providing HCV care for PWID.

Expert's Commentary

The main message of this manuscript is that in people who inject drugs (PIWD), after successful antiviral treatment, HCV re-infection is not an infrequent event. Unfortunately, no predictors of re-infection can be identified. Consequently, when prioritizing treatment in this population of patients, we should also estimate the re-infection's risk.

However, despite this important note of caution, the study provides additional information useful in controlling this risk of re-infection among PIWD. First of all, in patients who had been abstinent from the use of drugs for at least 6 months before the start of treatment, the risk of re-infection is not higher than 1.7/100 person year. By contrast, it increases up to 4.9/100 person year in case of relapse to IVDU. Therefore, trying to avoid IVDU relapse should be our main task. Secondarily, although predictors were not identified, in this study, re-infection was more frequent among younger individuals with low educational level. Based on these data among PIWD we can pursue a selective prioritization, restricting treatment to people with consolidate history of drug abuse discontinuation. Moreover, in order to prevent re-infection, in parallel with treatment, adequate educational programs highlighting lack of protective immunity and the likelihood of high risk of re-infection when sharing needles, syringes and injecting paraphernalia should be promoted. Strategies to prevent re-infection should be addressed in future studies

Alessandra Mangia, San Giovanni Rotondo, Italy