Regular hepatitis C testing among the HIV-negative gay men and other
men who have sex with men (MSM) participating in the Amsterdam
pre-exposure prophylaxis (PrEP) demonstration project (AmPrEP) has
revealed infection rates via sex previously only associated with
HIV-positive gay men. The incidence rate of re-infection in men
already treated for hepatitis C was even higher, resembling more the
incidence of bacterial sexually transmitted infections (STIs) such as
gonorrhoea.
AmPrEP principal investigator Elske Hoornenborg presented findings at the 22nd International AIDS Conference (AIDS 2018)
in Amsterdam. She commented that sexual health information and
encouragement to avoid behaviours that may spread hepatitis C were
important but that frequent testing and immediate hepatitis C treatment
were probably the only way to start bringing down the rates of
circulating hepatitis C in the gay community.
AmPrEP is still
ongoing. Starting in August 2015, it is due to end in December 2020 and
has recruited 374 MSM and two transgender women and offers them a choice
of daily or event-driven HIV PrEP.
In the meantime, on 10 July, the Dutch government announced that
it would support a heavily subsidised price of €12 a month for people
buying PrEP for a trial period of five years, forecasting that about
6500 people are expected to join the programme.
In AmPrEP,
participants are tested for hepatitis C every six months. The present
figures are from August 2015 to December 2017 and most of the people in
the study were followed for that whole time period.
There was already a quite high prevalence rate of 4.8% for hepatitis C infection among men tested when they joined AmPrEP.
There
were 12 new hepatitis C infections diagnosed up to December 2017. This
indicates an annual incidence of about 1%. This rate increased slightly
but not significantly during the second year.
The men newly
infected had an average age of 35, all but two had white ethnicity, and
all but one chose daily PrEP. Nine (75%) reported chemsex. They had an
average of 19 anal sex partners in the previous three months, and eight
partners with whom they were receptive and had not previously met.
The
1% rate is quite typical of rates of sexual hepatitis C infection among
HIV-positive gay men – but it hasn’t been seen in HIV-negative gay men
before.
Nine infections were of hepatitis C virus (HCV) genotype
1, with one each of genotypes 2, 3, and 4. Phylogenetic analysis showed
that eight out of the nine new hepatitis C genotype 1 infections fell
into three infection “clusters” of 21, 18 and eight members whose
hepatitis C was closely related.
In the cluster of 21 men, two
newly infected men shared the cluster with 17 HIV-positive and two
HIV-negative men already infected. In the cluster of 18, three newly
infected men shared it with eleven HIV-positive men and four
HIV-negative men already infected. And in the cluster of eight, there
were three new hepatitis C infections in HIV-negative men, two already
infected, and three HIV-positive men.
This shows that at least
some of the explanation for rising hepatitis C rates in HIV-negative men
– and why the rate has been so much higher in men with HIV – is that
‘serosorting’ behaviour, and especially the type where condomless sex is
only practised in men who are confident their partner has the same HIV
status as theirs, is now breaking down in the PrEP era, with a lot more
sex that can transmit hepatitis C taking place across the HIV
serodivide.
Of the 12 hepatitis C infections, six were of men already treated for and cured of hepatitis C already.
The
annual incidence rate for re-infection, given the relatively short
interval between cure and subsequent re-infection – was an
extraordinarily high 25.5% a year. This would be a record even for
sexually transmitted HIV and is unprecedented for hepatitis C in MSM.
Aidsmap.com
asked Dr Hoornenborg if these rates, more typical of hepatitis C
transmitted by unsterilised needles, might be due to transmission
between men injecting drugs during ‘chemsex’.
She said: “We think
not. We supply clean injecting equipment if needed, and our participants
who do inject drugs are adamant that they don’t share needles.
“We think it’s simpler than that: previously, hepatitis C was hard to cure, so by definition you couldn’t become re-infected.
“Now
you can, and we are finding that there is a subgroup of gay men whose
behaviour puts them at a risk of hepatitis C that’s comparable to other
STIs.
“It’s important to ask what risks they are taking and help
them avoid ones that can transmit hepatitis C. But the ultimate answer
to this is to test for hepatitis C as frequently as for other STIs and
to provide affordable hepatitis C treatment as soon as possible after
testing.”
However, she did flag up one other issue.
“Only
five of our newly infected men actually live in Amsterdam (42%). We know
some travel from towns quite a long way from here to get PrEP. However
they are travelling even further to encounter hepatitis C: we know from
their accounts that many probably caught in in cities like London,
Berlin and Paris, where they go for sex parties.
“We can only really tackle hepatitis C in gay men if we tackle it on a Europe-wide basis.”