Newswise — (New York, NY – July 21, 2011) Sexual transmission of hepatitis C virus (HCV) is considered rare. But a new study by researchers at Mount Sinai School of Medicine, working with the Centers for Disease Control and Prevention (CDC), provides substantial evidence that men with HIV who have sex with other men (MSM) are at increased risk for contracting HCV through sex.

The results of the study are published in today’s edition of the CDC’s Morbidity and Mortality Weekly Report.

HCV transmission primarily occurs through exposure to blood, and persons who inject drugs at greatest risk. But when Mount Sinai researchers observed a large increase in the number of new cases of HCV transmission among HIV-infected men who did not inject drugs, they took a closer look to examine the role of sexual transmission among these men.

The researchers identified 74 HIV-infected men between October 2005 and December 2010 who had documented new HCV infection and yet reported no other risk factor for HCV infection, including injection drug use. When they compared 22 of these men with a control group of 53 closely matched HIV-infected MSM who did not have HCV infection, they found that the men who had recently contracted HCV were 23 times more likely to have had unprotected anal sex with men. In addition, HCV genetic analysis suggested that HCV was transmitted within social networks of these men, consistent with the presence of a city-wide epidemic.

“While hepatitis C is rarely transmitted among stable heterosexual couples, this is clearly not the case among HIV-infected MSM in New York City,” said Dr. Daniel Fierer, Assistant Professor of Medicine and Infectious Diseases at Mount Sinai School of Medicine. “MSM, and to some extent their health care providers are generally not aware that having unprotected receptive sex can result in HCV infection. 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.”

“Our study suggests that HIV-infected MSM should take steps to protect themselves and others by using condoms. Also, health care providers should be screening these men for hepatitis C, and public education and outreach programs should include information about these risks,” Dr. Fierer concluded.

About The Mount Sinai Medical Center

The Mount Sinai Medical Center encompasses both The Mount Sinai Hospital and Mount Sinai School of Medicine. Established in 1968, Mount Sinai School of Medicine is one of few medical schools embedded in a hospital in the United States. It has more than 3,400 faculty in 32 departments and 15 institutes, and ranks among the top 20 medical schools both in National Institute of Health funding and by U.S. News & World Report. The school received the 2009 Spencer Foreman Award for Outstanding Community Service from the Association of American Medical Colleges.

The Mount Sinai Hospital, founded in 1852, is a 1,171-bed tertiary- and quaternary-care teaching facility and one of the nation's oldest, largest and most-respected voluntary hospitals. U.S. News & World Report consistently ranks The Mount Sinai Hospital among the nation's best hospitals based on reputation, patient safety, and other patient-care factors. Nearly 60,000 people were treated at Mount Sinai as inpatients last year, and approximately 530,000 outpatient visits took place.

For more information, visit www.mountsinai.org. Find Mount Sinai on: Facebook: http://www.facebook.com/mountsinainycTwitter @mountsinainycYouTube: http://www.youtube.com/mountsinainy