Traditionally, sexual activity has been regarded as an uncommon route of hepatitis C virus (HCV) transmission. According to the Centers for Disease Control and Prevention (CDC), sex with an HCV-infected person is “an inefficient means of transmission,” and the National Institutes of Health (NIH) states that “changes in sexual practices are not recommended” for monogamous people with chronic hepatitis C.

This information – which appears in most basic hepatitis C educational materials and most doctors give their patients – is based on observational studies of stable, presumably monogamous, HIV negative heterosexual couples with one HCV positive partner.  Such studies have shown HCV sexual transmission rates ranging from 0% (no cases) to about 3%.

But a growing epidemic of apparently sexually transmitted acute HCV infection, primarily among HIV positive men who have sex with men (MSM), has led some experts to revisit this consensus.

An Emerging Epidemic?
Beginning in 2002, clinicians began reporting clusters of acute hepatitis C among HIV positive gay/bisexual men, first in London and Brighton in the U.K., and later in cities in France, Germany, the Netherlands, and Switzerland.  While there were only a few cases in 2000-2004, the numbers increased dramatically around 2005-2006, and the count has now reached the hundreds.

A large proportion of the newly coinfected men in the various cities had HCV genotype 4, which is generally uncommon in Europe.  Genetic studies showed that a majority of the men’s HCV strains were closely related, occurring in a number of well-defined clusters, suggesting transmission within sexual networks, and from network to network due to travel between the cities.

The men in these clusters had several sexual practices in common. Overall – though specific associations vary from study to study – men with acute hepatitis C were more likely to report fisting, unprotected anal sex, multiple sex partners, sex in a group setting (for example, at a sex club or bathhouse), other sexually transmitted diseases (STDs), and use of non-injected recreational drugs.

Now In the U.S.
As late as 2005, researchers from Canada and the U.S. were reporting very few cases of apparently sexually transmitted acute hepatitis C among MSM with no other risk factors, but this began to change around 2006. That year, Annie Luetkemeyer and colleagues published a report of nine cases of acute HCV infection among HIV positive men seen at San Francisco General Hospital (SFGH).

Speaking at a San Francisco community forum on sex and hepatitis C this past January, Brad Hare from the SFGH team reported that 42% of HIV positive men in the hospital’s Positive Health Program are coinfected with HCV, with a majority reporting only sexual risk factors.  Michael Allerton from Kaiser Permanente Northern California said that 10% of the health plan’s HIV positive members also have HCV, and in an informal survey Kaiser doctors estimated that 70% to 100% of their coinfected patients contracted HCV through sex.

At the Conference on Retroviruses and Opportunistic Infection (CROI) in 2007, Daniel Fierer from Mt. Sinai School of Medicine in New York City first reported on a group of HIV positive MSM with acute hepatitis C who showed evidence of unusually rapid liver disease progression.  At this year’s CROI in February, the Mt. Sinai team presented a comparison of the characteristics and risk behaviors of 20 men in their coinfected cohort and 60 similar men in the U.K.

The men in both groups were older than average for STD clinic patients, with a mean age of about 40 years.  The New York men were less likely than the U.K. men to report insertive (33% vs. 73%) or receptive (24% vs. 57%) fisting during the past 12 months.  Majorities in both cities reported both insertive and receptive unprotected anal sex.  While the New York men were about one-third as likely to use non-injection recreational drugs, they reported more sharing of implements for drug smoking (48% vs. 20%) or injection (15% vs. 2%). Unlike European cohorts, 90% of the New York men had HCV genotype 1 and none had genotype 4.

Role of HIV
As noted, most of the recent cases of apparently sexually transmitted acute hepatitis C have been seen in HIV positive gay/bisexual men; in Paris, an HIV positive woman was among the newly coinfected.

This observation suggests that HIV may increase the risk of contracting HCV.  It is already known that HIV positive people are less likely to spontaneously clear HCV without treatment, do not respond as well to interferon-based therapy, and appear to experience more rapid liver disease progression.

Disturbingly, Fierer reported that among 24 newly HCV-infected HIV positive men who underwent liver biopsies an average of four months after their first elevated ALT test, 18 (75%) already had moderate (stage 2) fibrosis, and only two had no evidence of fibrosis.  However, among 10 individuals who completed treatment with pegylated interferon plus ribavirin, eight (80%) achieved sustained virological response – comparable to the success rate for HIV negative people.

HIV causes progressive immune suppression, but across the European and U.S. cohorts, newly coinfected HIV positive men had relatively high CD4 T-cell counts overall, above the current threshold for starting antiretroviral therapy (350) and sometimes as high as 500.

Another possible explanation is that HIV positive men are more likely to be tested for hepatitis C. While on antiretroviral therapy, HIV patients should have their liver enzymes monitored regularly to check for drug toxicity.  If an individual has elevated ALT with no other apparent cause, they are likely to be tested for HCV, and thus may be diagnosed during acute infection, which is often asymptomatic.  In contrast, HIV negative men seldom receive regular HCV screening.  “I think if we start looking for it, we’re going to start finding it,” Allerton predicted at the forum.

However, the few studies that have looked at acute HCV infection among HIV negative men have not seen high rates.  In Brighton, where all sexual health clinic clients have been routinely screened for HCV since 2000, several new HCV infections did turn up in HIV negative men, but their rate was 13 times lower than that of HIV positive men.<

Growing Awareness
Awareness of the potential for sexual transmission of HCV has begun to emerge among gay men, particularly within groups – including the leather/BDSM (bondage & discipline/sadism & masochism) community – that engage in practices associated with transmission.  Unfortunately, the awareness of healthcare providers may be lagging: several forum participants related that they were refused HCV testing if they had never injected drugs.

The specific sexual risk factors for sexual HCV transmission remain unclear, since study results are mixed. Unlike most studies, for example, Fierer found that receptive anal or oral sex were associated with acute HCV infection, while fisting was not. But correlation does not necessarily imply causality.  Multiple risk factors tend to occur together, and most gay/bisexual men do not engage in only a single sexual activity.

In its latest hepatitis C information, the CDC acknowledges that “the risk of transmission from sexual contact…increases for those who have multiple sex partners, have a sexually transmitted disease, engage in rough sex, or are infected with HIV.”

Larry Shockey, who hosts fisting parties now strongly encourages the use of gloves for fisting and uses a strong quaternary disinfectant on all play equipment before and after each use. HCV is harder to kill than HIV, and can live longer outside the body. Very small amounts of blood on surfaces and implements (e.g., whips, canes, needles for play piercing) – which may not even be visible – can potentially spread the virus.

Importantly, HIV positive men who have unprotected sex only with other HIV positive men still remain at risk for hepatitis C.

While small amounts of HCV may be present in semen, Hare said that blood is “probably the major route of exposure” to HCV during sex. Anal sex may be an efficient route of transmission because the rectal lining is prone to damage that could allow contact with blood – especially during prolonged sex facilitated by drugs such as crystal meth.

“HCV may have risk factors we don’t understand yet because the studies haven’t been done,” noted Allerton.

© 2009 Hepatitis C Support Project

Direct link: http://www.hcvadvocate.org/news/newsLetter/2009/advocate0409.html#6