Intensive screening for hepatitis C, treatment and risk
reduction counselling have led to sustained declines in hepatitis C prevalence
and new cases of hepatitis C among gay and bisexual men living with HIV in the
Swiss HIV Cohort, researchers report in the journal Clinical Infectious
Diseases.
The findings provide compelling evidence that so-called ‘micro-elimination’
efforts to diagnose and cure hepatitis C in specific groups with a high prevalence
of the virus not only eliminate chronic infections but also limit new
infections – and that this effect is sustained over several years.
The Swiss HCVree Trial took place in 2015 and 2016 (see
a report on the preliminary findings here). All gay and bisexual men in the
Swiss HIV Cohort underwent screening for chronic HCV infection and those with
detectable virus were offered direct-acting antiviral treatment. Participants
were screened again in 2017 and testing showed that new infections had fallen
by 57% and the prevalence of hepatitis C in the study participants had fallen
by 84%.
Study investigators have continued to test Swiss HIV Cohort
participants regularly for hepatitis C. In Clinical Infectious Diseases,
the investigators report on follow-up data to the end of 2019.
During 2019, 4641 of the 4804 gay and bisexual men enrolled
in the Swiss HIV Cohort were tested for hepatitis C RNA. Twenty-eight cases of
chronic infection were detected, a prevalence of 0.6%. Eleven of the 28 infections
were classified as new infections, including two reinfections.
The population screened in 2019 was not identical to the
HCVree study population; 1463 either joined the cohort after 2016 or had not
undergone screening in 2015-2016, and 537 people who had been screened in
2015-2016 had either dropped out of the cohort or had missing samples. In total,
60% of the cohort (n=2812) were screened at the study outset, again in 2017 and
in 2019.
Among those who participated in all phases of testing,
prevalence fell from 5.1% in 2015-2016 to 1% in 2017 and 0.4% in 2019.
Among the cohort as a whole (5352 participants with 40,483 person-years
of follow-up), HCV incidence declined from 0.54 per 100 PYs in 2010 to 0.34 per
100PYs in 2015, 0.31 per 100PYs in 2017 and 0.19 per 100PYs in 2019.
The decline in HCV incidence and prevalence in the Swiss HIV
Cohort follows similar observations in the Netherlands
(in all people with HIV), Australia
and France
(in gay and bisexual men).
Chronic HCV infection in 2019 was associated with a
detectable viral load, a lower current CD4 count and a lower nadir CD4 count,
as well as a history of injecting drug use. Age, gender and ethnicity did not
affect the risk of chronic infection in 2019. The study investigators say that
the medical histories of people with chronic HCV infection in 2019 show
co-morbidities and adherence difficulties, indicating that micro-elimination of
hepatitis C in people with HIV will require intensive support for some patients.
Phylogenetic analysis, which looks at the relationship
between genetic patterns of different viruses, showed a cluster of new infections
associated with international travel links. Efforts to achieve micro-elimination
among gay and bisexual men with HIV in one country are likely to be challenged
by mobility and connections with settings where micro-elimination has been less
successful, so concerted international action to reach the WHO HCV elimination
goals is needed, the study investigators conclude.