High rates of reinfection in people who inject drugs are a
sign that access to treatment is improving, not a sign of failure, and should
prompt retreatment, not stigmatisation, Australian hepatitis researcher Greg
Dore says in the Journal of Viral
Hepatitis this month.
He was commenting on a recently published study of hepatitis
C treatment and hepatitis C virus (HCV) reinfection among high-frequency injectors in Dundee, Scotland.
The Eradicate study was designed to evaluate engagement in
treatment, cure rates and reinfection rates among active injectors attending
needle and syringe programmes in the city. The study defined active injecting
as injecting within the previous week, in contrast to other studies in people
who use drugs, which required a period of abstinence from injecting prior to treatment
or required participants to be receiving opioid substitution treatment (OST).
Everyone attending the main needle and syringe programme in
Dundee between January 2012 and July 2016 was tested for hepatitis C antibodies
by dried blood spot testing each year. Everyone who tested positive for
hepatitis C was offered treatment with pegylated interferon and ribavirin. Anyone
who opted for treatment and who had injected in the past week was eligible to
join the study.
Of 745 tested for HCV, 92 tested positive for HCV RNA and 69
joined the study, together with 36 people already diagnosed with chronic HCV
infection. Ninety-four eventually started treatment. Participants had a median
age of 34 years, just over one in five were homeless or living in a hostel and
12% spent time in prison during the treatment period. The median injecting
frequency was 6.5 times a week and 54% injected at least once day.
Almost all participants had 100% needle and syringe
provision; 82% received needles and syringes sufficient to cover all reported
injections and 62.5% were already receiving OST prior
A high proportion of participants achieved a cure of
hepatitis C on pegylated interferon and ribavirin (and a protease inhibitor for
genotype 1 infections). Eighty-two per cent achieved a sustained virologic response. Thirty-seven
people with genotype 1 infection received simeprevir or telaprevir in
addition to pegylated interferon and ribavirin, following NHS guidelines during
the study period. There was no difference in cure rate according to genotype.
Adherence to OST was high during
the study; 93.8% of those who began the study on OST remained on OST throughout
Of the 77 participants who achieved a sustained virologic
response, five became reinfected with HCV within six months of their 12-week
post-treatment follow-up visit, a reinfection rate of 23.53 per 100
person-years of follow-up. After 18 months, 15 of 77 had been reinfected, a cumulative
18-month rate of 21.49 per 100 person-years. No factors were significantly
associated with reinfection in univariate analysis.
Despite the use of older regimens, the study achieved a high
cure rate in active drug users. Investigators say that a higher cure rate would
be possible with more effective, better tolerated direct-acting antivirals that
can be taken for eight or 12 weeks.
The reinfection rate in this study was much higher than
reported in a recent meta-analysis of studies (1.77 per 100 person-years) but
the investigators point out that reinfection studies in higher-risk populations
cover people who were not active injectors during the HCV treatment period. The
HCV reinfection rate in this study is similar to the community incidence of HCV
“The high HCV incidence and reinfection rates highlight the
failure of current coverage and intensity of harm reduction interventions to minimize
injecting risk,” say the investigators. The population would benefit from “a
broader programme of social and psychological interventions […] to reduce
The high reinfection rate “demonstrates that we have
successfully engaged with and treated a high-risk injecting population who
should be targeted as part of any successful treatment as prevention (TasP)
strategy,” the researchers conclude.
In an accompanying Comment article, Professor Greg Dore of the
Kirby Institute, University of New South Wales, Sydney, said that modelling of
treatment uptake in Australia suggests that reinfection rates among people who
inject drugs can be expected to rise until 2023 if Australia continues to
achieve high rates of treatment among drug users, before beginning to decline as
the number of people who inject drugs with chronic HCV infection begins to
“Intensive injecting network exploration and screening could
be utilised for those who develop HCV reinfection,” he says, noting that sexual
partners are often injecting partners too. Ongoing monitoring of reinfection,
point-of-care technologies that can detect HCV RNA – such as fingerprick
sampling – and rapid initiation of treatment will all contribute to efforts to
reduce reinfection in people who use drugs.