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.