The rate of re-infection with hepatitis C has fallen sharply
among people with HIV in Europe since the introduction of direct-acting
antivirals, the EuroSIDA cohort study reports in the journal HIV Medicine.
People who are cured of hepatitis C by interferon-based
treatment or direct-acting antivirals do not acquire immunity against
subsequent infections. Sharing of injecting equipment or condomless anal sex
can lead to re-infection and studies have reported high rates of re-infection
in some settings. Most of these findings have come from cohorts of gay and
bisexual men with HIV in western Europe and North America. Reported
re-infection rates in people who inject drugs have been much lower. There is
little evidence on re-infection rates in eastern Europe.
To investigate hepatitis C re-infection rates in people with
HIV, and whether these have changed over time, the EuroSIDA cohort
investigators looked for all people who had been cured of hepatitis C in the
cohort and who had at least once hepatitis C RNA test result in the two years after
they achieved a sustained virologic response.
EuroSIDA includes approximately 23,000 people with HIV in 35
countries in the European region, Israel and Argentina. Among these, 6915 had
ever tested positive for hepatitis C RNA and 1022 had been cured of hepatitis
C, had at least two years of follow-up and had been tested for hepatitis C RNA during
follow-up.
The study population was predominantly male (78%) and White
(86%) with a median age of 50 years. Just over half (52%) had acquired
hepatitis C through injecting drug use.
Nineteen per cent were cured of hepatitis C before 2014, 91%
by an interferon-based regimen. Twenty-one per cent were cured with an interferon-based
regimen in 2014 or after and the remainder (60%) were cured with a
direct-acting antiviral regimen in 2014 or after.
During the two-year follow-up period, 75 people were
re-infected with hepatitis C. Thirty-one of these re-infections occurred before
2014, 18 in people cured by interferon-based therapy in 2014 or after and 26 in
people cured by direct-acting antivirals in 2014 or after. The re-infection
rate was highest in the pre-2014 group (18%) and lowest in the direct-acting antiviral group (4%).
Whereas more than half of those treated before 2014 had injecting
drug use as their HIV transmission risk (58%), the proportion with injecting
drug use as a transmission risk factor fell significantly from 2014 (p = 0.03).
The median time to a positive HCV RNA test after being cured
was 8 months and did not vary over time.
The risk of re-infection was nearly 80% lower in people
treated with direct-acting antivirals in 2014 or after (adjusted odds ratio
0.21, 95% confidence interval 0.11-0.38) and around 55% lower in those who received
interferon-based treatment in 2014 or after (adjusted odds ratio 0.43, 95% confidence
interval 0.22-0.83), when compared to people treated before 2014.
The study investigators say that a possible explanation for
the reduced risk of re-infection after 2014 is the effect of wider treatment
availability and uptake on the prevalence of hepatitis C. A reduction in the
number of people with hepatitis C would lead to a reduction in the chance of acquiring
hepatitis C.
The study cannot demonstrate whether the risk of re-infection
is higher in one group or another as up-to-date information on injecting drug
use is not available.