Back HCV Prevention HCV Sexual Transmission AASLD 2011: Epidemic of Sexually Transmitted HCV among HIV+ Gay Men in Amsterdam Levels Off

AASLD 2011: Epidemic of Sexually Transmitted HCV among HIV+ Gay Men in Amsterdam Levels Off

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The epidemic of apparently sexually transmitted hepatitis C virus (HCV) infection among HIV positive men who have sex with men (MSM) in Amsterdam appears to have stabilized since 2008-2009, but monitoring and prevention efforts are still needed, according to data presented at the American Association for the Study of Liver Diseases Liver Meeting (AASLD 2011) last week in San Francisco.

Outbreaks of acute hepatitis C among HIV positive gay and bisexual men were first reported in the early 2000s, first in major cities in the U.K. and Europe and later in Australia and the U.S. Viral genetic analysis indicates that the cases cluster within sexual networks, but the precise risk factors for transmission remain poorly understood.

Anouk Urbanus from the Amsterdam Public Health Service and colleagues presented a 15-year overview of the hepatitis C epidemic among MSM seen at a large sexually transmitted disease clinic. Between 1995 and 2010 all clinic attendees were asked to participate in an anonymous survey about risk factors for blood-borne and sexually transmitted infections, and were tested for HIV and HCV antibodies.

The current study included all surveyed MSM. All HIV positive MSM -- regardless of HCV antibody status -- were tested for HCV RNA (retrospectively using stored samples from 1995 to 2006, prospectively from 2007 onward). Acute hepatitis C was defined as being HCV RNA positive with weak or negative HCV antibody response. The NS5B region of the viral genome was sequenced to look for patterns of transmission.

Results

  • The prevalence of positive HCV antibody status gradually increased over the first 8 years of the study period:
    • 1995: around 2.5%;
    • 2000: around 3.5%;
    • 2003: around 4.0%.
  • HCV prevalence increased substantially in 2004 and remained high for the next several years:
    • 2004: around 10.0%;
    • 2007: around 13.0%;
    • 2008: around 14.5%;
    • 2009: around 17.0%.
  • However, the HCV prevalence rate fell substantially the following year:
    • 2010: around 8.0%.
  • Looking at cases of acute hepatitis C, or recent infection, among HIV positive MSM, the numbers were smaller and the pattern somewhat different:
    • 1995: no acute cases observed
    • 1996: around 2.5%;
    • 1999: no acute cases;
    • 2000-2003: 2.0%-2.5%;
    • 2004: around 7.0%;
    • 2007: around 3.0%
    • 2008: around 4.0%;
    • 2009: no acute cases;
    • 2010: around 2.5%.
  • In a multivariate analysis during 2007-2010, the following factors were independent risk factors for HCV infection:
    • Unprotected anal intercourse: odds ratio (OR): 4.69;
    • History of injection drug use: OR 4.04;
    • Chlamydia: OR 2.04;
    • Use of the drug GHB: OR 1.89;
    • Fisting: association decreased over time from OR 2.52 during 2007-2008 to OR 0.99 during 2009-2010.
  • Phylogenetic analysis revealed a high degree of clustering specifically among gay/bisexual men.
  • HCV prevalence among HIV negative MSM remained low and stable, at around 0.5%, during 2007-2010.

"HCV prevalence substantially increased from 2000" but "appears to be leveling off," the researchers concluded. "Estimated HCV incidence declined after 2006," although the change was not significant.

They added that increased awareness and the introduction of routine HCV antibody testing of HIV positive MSM at the clinic after the first reports of the outbreak might have contributed to stabilization of the number of acute infections. Successful early treatment of acute hepatitis C might also play a role.

Nevertheless, they advised, "monitoring of HCV in both HIV positive and HIV negative MSM is still needed."

Investigator affiliations: Cluster of Infectious Diseases, Public Health Service Amsterdam, Amsterdam, Netherlands; Centre for Infection and Immunology (CINIMA), Academic Medical Center, Amsterdam, Netherlands; Department of Medical Microbiology and Infection Control, VU University Medical Center, Amsterdam, Netherlands; Department of Clinical Virology, Academic Medical Center, Amsterdam, Netherlands; Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, Amsterdam, Netherlands; Center for Infectious Disease Control, National Institute for Public Health and the Environment, Bilthoven, Netherlands.

11/18/11

Reference

A Urbanus, TJ van de Laar, JW Vanhommerig, et al. Insight into the hepatitis C epidemic among men who have sex with men; results from the STI clinic surveys in Amsterdam, 1995-2010. 62nd Annual Meeting of the American Association for the Study of Liver Diseases (AASLD 2011). San Francisco, November 4-8. 2011. Abstract 224.