incidence of hepatitis C infection is now four times lower in gay and
bisexual PrEP users than it was before direct-acting antivirals for the
treatment of hepatitis C became available without restrictions in
higher-income countries, Australian researchers reported this week at
the 24th International AIDS Conference in Montreal.
Hepatitis C prevalence rose among gay and bisexual men with HIV
during the decade before direct-acting antiviral treatment for the
infection became widely available in Europe and North America after
2015. Hepatitis C appeared to spread in sexual networks where
unprotected anal intercourse took place predominantly between men living
There have been concerns that increased use of PrEP and a reduction
in condom use among gay and bisexual men could lead to an increased
incidence of hepatitis C in HIV-negative gay and bisexual men, as a
result of more condomless sex between men with differing HIV statuses.
Michael Traeger and colleagues at the Burnet Institute and Monash
University, Melbourne, carried out a systematic review and meta-analysis
to investigate the incidence of hepatitis C during PrEP use in cohorts
of gay and bisexual men, as well as the prevalence of hepatitis C
antibody and chronic hepatitis C in gay and bisexual men starting PrEP.
The researchers identified 18 studies published between 2015 and 2022
that reported on incidence, conducted in Australia, North America and
Hepatitis C incidence was higher in studies that began
before broad access to direct-acting antivirals than in studies that
began follow-up after there was broad access.
Twelve studies that began follow-up prior to broad access reported
hepatitis C incidence ranging from zero cases per 100 person-years of
follow-up to 2.93 cases per 100 person-years of follow-up, but the
confidence intervals in many of these studies were wide. The
meta-analysis estimated a pooled incidence of 1.27 cases per 100
person-years prior to broad access.
After broad access – the timing varied from country to country – six
studies reported substantially lower incidence, in all cases below the
pooled average for the 18 studies in the meta-analysis, with a pooled
incidence of 0.81 cases per 100 person-years of follow-up.
The meta-analysis also found a higher prevalence of prior
hepatitis C exposure, indicated by hepatitis C antibody, and chronic
hepatitis C infection, shown by hepatitis C RNA, prior to broad
direct-acting antiviral access. Some people may clear hepatitis C
spontaneously after acute infection while treatment may have cured
others, but anyone exposed to the virus will retain antibodies, so
antibody testing is indicative of historical prevalence.
Before broad access, 1.75% of people starting PrEP had hepatitis C
antibodies, compared to 0.63% in the period after broad access was
Similarly, hepatitis C RNA prevalence was lower in PrEP starters
after broad access was enabled. In the earlier period, RNA prevalence
was 0.95%, whereas prevalence was 0.24% in the later period.
The study authors say that lower hepatitis C RNA
prevalence in the broader-access period is not fully explained by
greater enrolment of people with a lower risk of acquiring hepatitis C
as time went on. Instead, they say, it is likely that declines in the
prevalence of chronic and acute hepatitis C due to treatment prior to
wider access to PrEP explain the substantially lower incidence of
hepatitis C after broader access to direct-acting antivirals was
enabled. Treatment is likely to have reduced transmission in gay and
bisexual men’s sexual networks.