High hepatitis C reinfection rate in prison study highlights harm reduction needs

Keith Alcorn
Published:
20 April 2022

Hepatitis C reinfection rates were high in Australian prisoners who took part in a study of hepatitis C treatment in prisons, researchers from the University of New South Wales report in the journal Clinical Infectious Diseases.

Lack of harm reduction measures, high rates of injecting equipment sharing, low coverage of opioid substitution treatment and lack of surveillance for reinfection all contribute to the high reinfection rate, the study investigators conclude.

The SToP-C study enrolled people incarcerated in four Australian prisons between 2014 and 2019. Participants received direct-acting antiviral treatment and after completing treatment and being confirmed as hepatitis C-free, they were followed up every three to six months to check for reinfection with hepatitis C.

The first phase of the study demonstrated that a rapid scale-up of hepatitis C treatment in prisons led to a corresponding decline in the incidence of new hepatitis C infections in the prison populations – a treatment-as-prevention effect.

A second phase of the study evaluated post-treatment incidence of reinfection in people who remained within the prisons that participated in the study. Participants were tested for hepatitis C RNA every three to six months.

During the first phase of the study, 388 people received direct-acting antiviral treatment and 366 (69%) had either undetectable HCV RNA at the end of treatment or a sustained virologic response 12 weeks after completing treatment. End-of-treatment RNA was checked in order to detect early cases of reinfection that occurred less than 12 weeks after the completion of treatment.

The majority of participants in the first phase of the study were either transferred to other prisons or released from prison during the follow-up period, leaving 161 people who remained in study prisons and were tested at least once for HCV RNA after completing treatment. Participants were eligible for inclusion in the analysis if they were released during the follow-up period and subsequently returned to a study prison.

Study participants were predominantly male (92%), 95% had a history of injecting drug use, 67% had injected drugs during their current imprisonment, 44% had done so in the previous month and of those injecting in the past month, 90% had shared injecting equipment. Twenty-six per cent were receiving opioid substitution treatment, almost all in the form of methadone.

Eighteen participants were reinfected during a median follow-up period of nine months, an incidence of 12.5 cases per 100 person-years of follow-up. In people who reported recent injecting drug use and needle and syringe sharing, the reinfection rate was 28.7 per 100 person-years.

Reinfection was associated with recent injecting drug use and needle and syringe sharing. Compared to people who had not injected drugs recently, those who injected drugs and shared needles and syringes were approximately 15 times more likely to be reinfected with hepatitis C (adjusted hazard ratio 14.62, 95% CI 1.84-116.28, p=0.011). When the analysis was confined to those with injecting drug use in the previous month (n=61), reinfection was associated with sharing of injecting equipment (aHR 5.58, 95% CI 1.13-27.54, p=0.016).

The incidence of reinfection was highest 3-6 months after completing treatment and then decreased over time. The study investigators say that more frequent testing is needed post-treatment to detect cases of reinfection, especially during the first six months after completion of treatment. In people who were released after treatment and subsequently reincarcerated, 80% were reinfected after release from prison, reinforcing an observation from a recent Canadian study that showed infection risk for incarcerated people was highest just after release.

Eleven of 18 participants who became reinfected were subsequently re-treated and cured of hepatitis C again. One was released before re-treatment, another spontaneously cleared the virus and five had not completed re-treatment by the end of the analysis period. The study investigators say that frequent testing and speedy re-treatment has the potential to limit transmission in the prison population. In this study population, participants waited a median of 8 weeks between detection of reinfection and commencing re-treatment.

Much of the injecting drug use in prison involved the injection of opioid substitutes. Seventy-nine per cent (n=56) reported injecting methadone or buprenorphine and 20% reported methamphetamine use. Only 2% of those reported injecting drug use in the past month were receiving opioid substitution treatment, indicating significant diversion of opioid substitutes within the prison and inadequate OST provision.

Although the participating prisons provided bleach for cleaning injecting equipment, sterile injecting equipment was not available as a harm reduction measure in any prison. Achieving hepatitis C elimination in prison settings while minimising reinfection will require scale-up of harm reduction measures as well as surveillance for reinfection and rapid re-treatment, the study investigators conclude.

Reference

Carson JM et al. Hepatitis C reinfection following direct-acting antiviral treatment in the prison setting: the SToP-C study. Clinical Infectious Diseases, published online 1 April 2022.

DOI: https://doi.org/10.1093/cid/ciac246