Since
the early 2000s, doctors in the U.K. and elsewhere in Europe have reported outbreaks
of apparently sexually transmitted acute hepatitis
C virus (HCV) infection among mostly HIV positive
men who have sex with men (MSM).
Yet
while a small number of similar cases have also been reported
in Australia and in the U.S., the overall prevalence of HCV antibody positivity
remains low among MSM who do not inject drugs, according to a Public Health
Reports supplement devoted to viral hepatitis.
Despite the recent spate
of HCV transmissions linked to sex and non-injection drug use, the authors emphasized
that, "Large or repeated percutaneous exposures to blood, such as through
transfusion from unscreened donors or injection drug use, have been the primary
sources of infection." They added that, "Sexual transmission occurs,
but appears to be inefficient compared with other sexually transmitted viruses."
The
authors acknowledged that recent reports of increasing HCV infection among HIV
positive MSM who are not injection drug users (IDUs) has raised concern about
sexual transmission of HCV and prompted some healthcare providers and advocates
to suggest that all MSM should be routinely tested for hepatitis C.
To
assess whether such routine testing might be valuable, they compared the prevalence
of HCV antibodies among non-IDU MSM and "other" (i.e., heterosexual)
non-IDU men at sexually transmitted disease clinics and HIV testing and counseling
programs in New York City, Seattle, and San Diego during the 1999-2003 period.
They found that among male and female IDUs, the prevalence of detectable
HCV antibodies was 47%-57% across the sites, for an overall prevalence of 51%.
By contrast, among 1699 non-IDU MSM, just 26 (1.5%) tested positive for
HCV antibodies. Among 3455 "other" non-IDU men, the rate was 3.6%, indicating
that the gay men had a lower, rather than higher, rate of HCV positivity.
According
to the authors, these findings argue against routine testing of all MSM who do
not inject drugs.
"With decreasing resources to support prevention
activities in publicly funded clinics, targeting HCV testing to those most likely
to be infected is important," they wrote. "Although sexual transmission
of HCV is possible, it appears to be inefficient, and testing MSM without a risk
factor for which routine HCV is currently recommended is not supported by data
in this report or other studies."
The authors do recommend that HIV
positive MSM should be tested for HCV infection regardless of reported risk factors,
"as coinfection has important implications for progression of and therapy
for both diseases."
Further, the
Public Health Reports study concluded in 2003. In the European cities that have
reported acute HCV outbreaks among MSM, there were only a few cases reported in
2000-2003, with the number increasing in the ensuing years. Though similar outbreaks
have not yet been reported in the U.S., some experts believe it is only a matter
of time.
10/05/07
Reference J
Buffington, PJ Murray, K Schlanger, and others. Low Prevalence of Hepatitis C
Virus Antibody in Men Who Have Sex With Men Who Do Not Inject Drugs. Public
Health Reports 122 (suppl 2): 63-67. September 2007.
