- Category: Acute Hepatitis C
- Published on Friday, 29 July 2011 00:00
- Written by Liz Highleyman
Hepatitis C virus (HCV) is transmitted by sex between HIV positive gay/bisexual men and sexual transmission is responsible for several local epidemics, including one in New York City, according to study findings published recently in the CDC's Morbidity and Mortality Weekly Report.
Most studies have shown that sexual transmission of HCV is uncommon between stable heterosexual partners, leading public health authorities to regard sex as a low-risk transmission route.
But the same does not hold true for all populations. Starting in 2000, researchers in the U.K. began reporting clusters of apparently sexually transmitted acute HCV infection among urban HIV positive men who have sex with men (MSM).
Over the course of the decade similar local epidemics were reported in several large cities in Europe, Australia, and the U.S. A number of associated risk factors have been implicated -- which are not consistent across studies -- including unprotected anal intercourse, fisting, use of sex toys, group sex, presence of other sexually transmitted diseases, and non-injection recreational drug use. Transmission is thought to be due to exposure to HCV in blood, not semen. Most men in these clusters report no history of injection drug use.
The few studies that have looked at HCV infection among HIV negative MSM have found transmission rates more like those of HIV negative heterosexuals. This suggests that HIV infection itself plays a key role in facilitating HCV infection, though it is not clear why as the risk extends to people with high CD4 cell counts who have not yet sustained serious immune system damage.
Daniel Fierer and colleagues from Mount Sinai School of Medicine have been following a cluster of acute HCV infections among HIV positive gay/bisexual men in New York City for several years. They have presented reports at numerous conferences about risk factors for HCV acquisition and unusually rapid liver disease progression in this population; their data have now been published in the July 21, 2011, Morbidity and Mortality Weekly Report.
- Between October 2005 and December 2010 the researchers identified 74 HIV positive men with documented new HCV infections who reported no traditional risk factors including injection drug use.
- The median age was 39 years and the median duration of HIV infection was 8 years.
- The group had well-controlled HIV disease overall, with a median CD4 cell count of 483 cells/mm3; 74% were on antiretroviral therapy and 68% had HIV viral load < 400 copies/mL.
- 81% had no HCV symptoms and 19% had jaundice (yellowing of the skin and eyes); most cases were detected due to ALT elevation.
- A case-control analysis of 22 HIV/HCV coinfected men and 53 HIV positive but HCV negative control subjects found that men with HCV were 23 times more likely to have had unprotected receptive anal intercourse with ejaculation (odds ratio [OR] 23.0).
- These men were 29 times more likely to have had sex while using methamphetamine (OR 28.6).
Other factors linked to HCV infection in a univariate analysis but no longer significant in a multivariate analysis included:
- Unprotected insertive anal intercourse (OR 2.6);
- Receptive fisting (OR 10.1);
- Insertive fisting (OR 7.9);
- Use of sex toys (OR 4.4);
- Group sex (OR 19.3);
- Sex while high on drugs (OR 11.4);
- History of syphilis (OR 8.8);
- History of gonorrhea (OR 5.0).
- Genetic analysis of HCV strains from 50 men (47 with genotype 1a and 3 with genotype 1b) showed 5 related clusters, suggesting transmission within social/sexual networks.
"MSM, and to some extent their healthcare providers are generally not aware that having unprotected receptive sex can result in HCV infection," said Fierer. "The good news is that the cure rate for new HCV infections is very high with early treatment, but without regular testing of the men at risk, these largely asymptomatic infections may be missed and this opportunity lost.”
As Fierer notes, acute HCV infection is often symptomatic or may cause only non-specific symptoms such as fever, fatigue, and malaise that can be mistaken for a flu. Recent HCV infections among HIV positive men were first identified because people taking antiretroviral therapy receive regular liver function tests to monitor for drug-related liver toxicity. Elevated levels of the liver enzymes ALT and AST can signal potential liver problems, prompting clinicians to test for hepatitis B and C.
But healthy people typically do not undergo regular liver enzyme testing. Over time, HCV infection can cause severe liver damage including cirrhosis and hepatocellular carcinoma. A large proportion of people with hepatitis C are not diagnosed until they progress to symptomatic liver disease years or decades after initial infection. The Mount Sinai researchers and others have found that this progression happens faster in HIV positive people.
“Our study suggests that HIV-infected MSM should take steps to protect themselves and others by using condoms," Fierer recommended. "Also, healthcare providers should be screening these men for hepatitis C, and public education and outreach programs should include information about these risks.”
An accompanying editorial note cautioned in particular that HIV positive men who have decided to practice unprotected sex with positive partners ("serosorting") can still transmit HCV and other sexually transmitted infections.
Similar studies have found that other sexual activities besides anal intercourse are more closely associated with acute HCV in this population. This suggests that other safer sex measures -- such as wearing gloves for fisting and thoroughly cleaning sex toys -- may also be protective.
DS Fierer, SH Factor, AJ Uriel, et al. Sexual Transmission of Hepatitis C Virus Among HIV-Infected Men Who Have Sex with Men-- New York City, 2005-2010. 60(28):945-950 (free full text). July 22, 2011.
Mount Sinai School of Medicine. Hepatitis C Transmitted by Unprotected Sex Between HIV-Infected Men. Press release. July 20, 2011.