Thus, the major objectives of this study were to quantify the risk for sexual transmission of HCV infection from chronically infected subjects to their long-term

heterosexual partners and identify specific sexual practices associated with that risk. CI, confidence interval; HBV, hepatitis B virus; HCV, hepatitis C virus; HIV, human immunodeficiency virus; IDU, injection drug use; PCR, polymerase chain reaction. The recruitment phase of the study was conducted in Northern California sites between January 2000 and May 2003. Recruitment began by first identifying a known HCV-positive subject (referred to as the index subject) from multiple sources, including liver clinics at the University of California at San Francisco, members of Kaiser AZD3965 concentration Permanente Medical Care Plan in Northern California, California Pacific Medical Center and affiliated clinics, other community-based practices in the greater San Francisco Bay Area, and blood donors from Blood Centers of the Pacific/Blood Systems Research Institute. Researchers contacted index subjects for study enrollment, and if eligible based on prescreening, contacted their sexual partner. Criteria for study participation selleck chemical by each couple included a heterosexual relationship for a minimum of 36 months, monogamy

for the duration of the relationship reported by both partners, and a minimum of three sexual contacts by the couple in the preceding 6 months. Couples were excluded

if either partner had known HIV or HBV infection, had prior organ transplantation, or was currently using antiviral or immunosuppressive therapy, or if both partners reported a history of injection drug use (IDU). Partners of each couple were interviewed independently by phone (76%) or in person (24%) by trained interviewers, with no difference in completing a questionnaire by interview type. Detailed information was obtained on sexual (-)-p-Bromotetramisole Oxalate history with the study partner (Supporting Information), nonsexual household exposures (sharing of personal items, including nail grooming tools, razors, and toothbrushes), and all other known risk factors for HCV acquisition. The risk period for sexual transmission was defined using a uniform method to capture sexual activities over the entire duration of the couple’s relationship. Sexual histories were collected in discrete time intervals defined by events in each participant’s sexual history and beginning from the time of first sexual contact with the current partner up to the time of interview. Each participant identified life events such as pregnancy, childbirth, medical illness, and absences that significantly changed sexual activities with their study partner and the corresponding year and age for each life event.