Heterosexual Sex Not a Major Risk Factor for Hepatitis C Virus Transmission

SUMMARY: Sex between women and men does not appear to be a common route of hepatitis C virus (HCV) transmission, according to study results reported last week at the 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2010) in Boston. These findings confirm prior research showing a low rate of heterosexual HCV transmission, in contrast with the higher rate reported for HIV positive gay and bisexual men.

By Liz Highleyman

Over the past decade, researchers have reported several outbreaks of acute hepatitis C among men who have sex with men that appear to be due to sexual transmission. This conflicts with public health guidelines stating that sexual transmission of HCV is uncommon, but these were based on studies of monogamous heterosexual couples.

To shed further light on this issue, Monina Klevens from the U.S. Centers for Disease Control and Prevention (CDC) and colleagues collected data from surveillance of new HCV infections reported during 2005-2009 by health departments in Colorado, Connecticut, Minnesota, Oregon, and 34 counties in New York State.

Included cases met clinical criteria (acute illness with at least 1 sign or symptom of viral hepatitis and either jaundice or elevated alanine aminotransferase [ALT]) or laboratory criteria (confirmed positive HCV antibody test) for acute hepatitis C.

The health departments collected demographic and clinical data for each case, and asked patients or their healthcare providers for information about 21 potential HCV risk behaviors occurring 2 weeks to 6 months before the onset of symptoms.

Results

• A total of 575 cases of acute HCV infection were reported.
• 63 cases (11.0%) had no reported risk factors and were excluded from the present analysis.
• Of the remaining 512 cases, 247 patients (48.2%) reported using drugs.
• 202 people (39.5%) reported exposure through heterosexual sex.
• 20 people (3.9%) reported sex with a same-sex partner.
• Most of the infected individuals who reported heterosexual sex (126 of 202) or homosexual sex (14 of 20) also reported drug use.
• Drug use increased with the number of sexual partners: 

          --79.0% of people with > 5 partners;
          --76.5% with 2-5 partners;
          --54.6% with 1 partner.

• 42 out of 202 people (20.8%) reported sexual contact with a person confirmed or suspected to have HCV infection.
• Just 19 out of 202 heterosexuals (9.4%) reported no other risk behaviors other than sex with an opposite-sex partner.
• Individuals who had heterosexual sex as their only risk behavior were significantly older than those with more risk factors (43 vs 35 years, respectively), but otherwise similar including race/ethnicity. 

Based on these findings, the investigators stated that most people with acute HCV infection who had 1 or more heterosexual partners also had other risk factors, and concluded that "heterosexual transmission may not be an important risk factor for HCV in the U.S."

Investigator affiliations: CDC, Atlanta, GA; Colorado Dept. of Public Health and Environment, Denver, CO; Connecticut Dept. of Public Health, Hartford, CT; Minnesota Dept. of Health, St. Paul, MN; New York State Dept. of Health, Albany, NY; Oregon Public Health Div., Portland, OR.

9/21/10

Reference
M Klevens, D Daniels, K Iqbal, and others. Is Heterosexual Transmission an Important Risk Factor for Hepatitis C in the United States? 50th Interscience Conference on Antimicrobial Agents and Chemotherapy (ICAAC 2010). Boston, September 12-15, 2010. (Abstract V-1787).

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