Hepatitis C Seroprevalence Among Prison Inmates Since 2001: Still High but Declining

Objectives

Although the hepatitis C epidemic in the United States disproportionately affects correctional populations, the last national estimates of seroprevalence and disease burden among these populations are more than a decade old. We investigated routine hepatitis C surveillance conducted in state prison systems and updated previous estimates.

Methods

We surveyed all U.S. state correctional departments to determine which state prison systems had performed routine hepatitis C screening since 2001. Using seroprevalence data for these prison systems, we estimated the national hepatitis C seroprevalence among prisoners in 2006 and the share of the epidemic borne by correctional populations.

Results

Of at least 12 states performing routine testing from 2001 to 2012, seroprevalences of hepatitis C ranged from 9.6% to 41.1%. All but one state with multiple measurements demonstrated declining seroprevalence. We estimated the national state prisoner seroprevalence at 17.4% in 2006. Based on the estimated total U.S. correctional population size, we projected that 1,857,629 people with hepatitis C antibody were incarcerated that year. We estimated that correctional populations represented 28.5%–32.8% of the total U.S. hepatitis C cases in 2006, down from 39% in 2003.

Conclusions

Our results provide an important updated estimate of hepatitis C seroprevalence and suggest that correctional populations bear a declining but still sizable share of the epidemic. Correctional facilities remain important sites for hepatitis C case finding and therapy implementation. These results may also assist future studies in projecting the societal costs and benefits of providing new treatment options in prison systems.Hepatitis C virus (HCV) is the most common chronic bloodborne pathogen in the United States, both in the general population and among prisoners. National Health and Nutrition Examination Survey (NHANES) data from 2003–2006 suggested an overall anti-HCV serum antibody prevalence (seroprevalence) of 1.3% among household-dwelling populations.¹ Others have suggested that the national seroprevalence may be closer to 2.0% after adding prisoners, homeless people, and other populations not sampled by NHANES.² However, enrollment in NHANES requires several months of housing stability,³ so people with unstable or intermittent housing at any time during a given year are unlikely to participate. Thus, the number of infected people not in households during a period of time, rather than at a single point, should be added to the national seroprevalence estimate.Unsafe injection practices, including injection drug use, are the primary risk factors for HCV infection in the general population.⁴ National HCV prevalence is greater among men than women, and among non-Hispanic black people compared with non-Hispanic white people.¹ Prevalence peaks among individuals born between 1945 and 1965.⁵HCV infection disproportionately affects those who have been in jails and prisons. Although men (compared with women) and black people (compared with white people) are disproportionately incarcerated, the most likely cause for this infection rate disparity is injection drug use, which is both a risk factor for the disease and a criminal behavior.⁶ Hammett et al. estimated that correctional populations in 1997 accounted for 29.4%–43.2% of the total U.S. hepatitis C case burden.⁷ In 2003, the Centers for Disease Control and Prevention (CDC) reported that 16%–41% of inmates had serological evidence of prior HCV exposure, based on data derived from eight states. CDC also estimated that correctional populations bore 39% of the disease burden.⁸The 1976–1980 birth cohort currently comprises the largest proportion of state prison, federal prison, and local jail populations.⁹ As the birth cohort with peak HCV prevalence (1945–1965) ages out of crime-prone years, its contact with the criminal justice system will decline. Hence, the prevalence of HCV among correctional populations should fall. Two states included in the 2003 CDC analysis have since updated their seroprevalence estimates and both demonstrated declines. In Rhode Island, a sampling of prisoners in the mid-1990s showed an HCV seroprevalence of 37%,¹⁰ but seroprevalence dropped to 23% from 1998 to 2000.¹¹ In California, seroprevalence dropped from 41% of entering inmates in 1994¹² to 34% among a small cohort of entrants tested in 2001.¹³It has been estimated that 65%–75% of people with viral hepatitis are unaware of their status.¹⁴ Inmates are likely to be at the upper end of this range.¹⁵ Correctional facilities have represented rich sources for case finding. Once identified, new cases can be directed to treatment programs either in prison or the community. The need to initiate treatment before release for each case is contingent upon multiple factors. One determinant is whether the expected duration of incarceration is longer than the time required for treatment, which is currently one year but becoming shorter.¹⁶Prison health-care planners would benefit from up-to-date information regarding the number of hepatitis C infections in their systems. Currently, the U.S. lacks data on the prevalence of HCV among prisoners and the share of the epidemic borne by incarcerated individuals since the last national estimates were derived a decade ago.^7,8 We investigated routine HCV surveillance conducted in state prison systems to update estimates of the national prison HCV seroprevalence and the share of the epidemic borne by inmates and releasees. We hypothesized that HCV prevalence was falling nationwide among prisoners and that imprisoned populations represented a reduced share of the hepatitis C epidemic.