Hepatitis C Virus Seroprevalence in High-Risk Populations Identified for Screening in Philadelphia

BACKGROUND: Hepatitis C virus (HCV) is the most common chronic bloodborne infection in the United States, infecting as many as 3.9 million people, a 1.9% national seroprevalence.75% of people living with the infection are unaware of their infection, though various risk factors have been shown to be associated with HCV infection, including injection drug use, sexual contact with an HCV infected individual, and history of incarceration. In order to inform current and future efforts to provide early diagnosis, care, and preventative services for HCV positive individuals, the Philadelphia Department of Public Health (PDPH) estimated HCV seroprevalence in multiple settings to prioritize targeted HCV screening.

METHODS:   In 2012, the Philadelphia Department of Public Health (PDPH) performed two anonymous and blinded seroprevalence studies within two high-risk populations – STD clinic attendees and Philadelphia Prison System inmates. Specimens were collected from all inmates on intake and from clinic attendees with blood drawn for STD testing. Samples were de-identified at the time of testing, except for age (<30 and ≥30 years) and gender. In addition, HIV/AIDS surveillance data (eHARS) and HCV testing registry were matched to estimate laboratory-confirmed HCV coinfection amongst HIV positive individuals diagnosed between 2000 and 2010.

RESULTS:   Of the 23,539 individuals reported with HIV/AIDS, 1,289 inmates, and 1,048 STD clinic attendees most were male – 70.9%, 82.8%, and 66.7%, respectively. For those with HIV, 13.4% were identified as having a HCV+ test reported. Overall HCV seroprevalence was 12.1% (95%CI: 10.4-14.0) for inmates, and 1.7% (95%CI: 1.1, 2.7) for clinic attendees. In each population, males 30 years and older had high seroprevalence – 17.1% (95%CI: 14.1-20.5) for inmates, 14.1% (95%CI: 13.6- 14.7) for those with reported HIV, and 4.9% (95%CI: 2.9-8.0) for STD clinic attendees. HCV seroprevalence was high in other groups – HIV+ females 30 and over (14.6%; 95%CI: 13.7-15.5), female inmates (12.8%; 95%CI: 8.8-17.7), and male inmates under 30 years (6.7%; 95%CI: 4.8-9.1). Outside of prison populations, HCV in those under 30 years old was low (<1%).

CONCLUSIONS:   In Philadelphia, the seroprevalence of HCV in screened populations varied (0.0-18.5%) depending on the setting, age, and sex of persons screened. Conducting seroprevalence studies in various settings and bringing together available data sources has allowed the local Health Department to target resources for more effective screening activities.