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Hepatitis C virusinfection in prisonsCorresponding author:Ms Emma R Miller (MPH)Discipline of Public HealthSchool of Population Health and Clinical PracticeUniversity of AdelaideDr Peng Bi (MBBS, PhD)Discipline of Public HealthSchool of Population Health and Clinical PracticeUniversity of AdelaideAssociate Professor Philip Ryan (MBBS, FAFPHM)Discipline of Public HealthSchool of Population Health and Clinical PracticeUniversity of AdelaideHepatitis C virus (HCV) infection is one of the mostcommonly notified communicable diseases in Australia.Nationally, the HCV-prevalence (the proportion of thepopulation infected) is estimated at approximately1-1.5% and about 20,000 infections are newly notifiedeach year. 1, 2 Approximately 13,500 notifications havebeen made to the South Australian surveillance systemsince the introduction of mandatory notifications in thisjurisdiction in 1995 (Communicable Disease ControlBranch, Department of Health, surveillance data 2006).The number of infected persons around the world isestimated to be between 170 and 300 million people. 3-5Much of the escalating disease prevalence can beattributed to the high chronicity rate of the infectionup to 85% of those infected fail to clear the virus 6,8in combination with relatively low treatment uptake. 9Although only a small proportion of those infectedwill go on to develop the more severe sequelae ofthe disease, such as liver cirrhosis and hepatocellularcarcinoma, 8, 10-12 the sheer size of the infected populationhas clear and serious implications for health resourcesand community health.While injecting drug use is widely accepted as themost common primary risk factor for HCV infection,history of imprisonment has also been independentlyassociated with infection. 13-16 Approximately 10% ofall South Australian notifications for HCV in 2002 werereceived from the state’s prisons, as were 25% ofthose cases confirmed as new infections (or ‘incident’)cases. 17 Nonetheless, there have been relatively fewstudies on the prevalence of HCV-infection within prisonpopulations and only a few studies have investigatedHCV transmission in this particular setting. There hasbeen no previous work on HCV-infection in SouthAustralian prisons. The small amount of publishedwork in this area suggests that HCV prevalence amongprisoners is many times higher than that of the nonincarceratedpopulation. High background prevalencewill greatly increase the HCV risk for all individualsentering the prison system. High prison rates of HCV arepotentially an important contributor to escalating rates inthe general population.This paper reviews some of the literature on HCVin prisons, before briefly introducing a statewidestudy being undertaken by the University of Adelaide(Discipline of Public Health) in South Australian prisonsin conjunction with the South Australian Department ofHealth, the Department for Correctional Services andthe South Australian Prison Health Services. The studyis investigating the prevalence and transmission of HCVin the South Australian prison population. Some of theearly results from the study are also presented.HCV infection in prisons: what do we already know?There are a number of difficulties for researchers toovercome when investigating HCV infection in prisonpopulations. As discussed by Dolan, 18 two distinctpopulations exist within prisons, which are defined bytheir use of injection drugs. This has implications forsampling strategies when studying HCV prevalence inprison populations. Shorter periods of incarceration areassociated with nonviolent, drug-related offences, withthis offender sub-population likely to be at greater riskof HCV infection. Thus, the prevalence of HCV in prisonentrants might not necessarily be applicable to theoverall prison population. 19 Cohort (or follow-up) studies,usually incorporating serial HCV testing, will tend toexperience greater losses to follow-up in those servingshorter sentences, resulting in HCV transmissionestimates which are likely to be lower than the true rateof transmission in the prison.Despite these and other difficulties, all of the publishedstudies on HCV in prison have been able to demonstratevery strong evidence of the association betweeninjecting behaviour and, in particular, sharing injectingequipment and HCV infection in prisoners. Despite aclear overlap between injecting and tattooing practiceamong prisoners, 13, 18 most studies that investigatedtattooing in prison as a risk factor found there wasan excess risk for HCV infection associated with thispractice. 20-22 Sharing injecting equipment in prison isthe principal risk factor, however, with the scarcityof new equipment meaning that a single syringe isgenerally used multiple times by a very large numberof prisoners. 23-25 There is evidence that a small butsignificant number of prisoners are initiated into sharing13, 20,or injecting for the first time whilst incarcerated.26, 27The literature also suggests that, for some, riskbehaviours learnt in prison continue after release. 28-3016
HCV prevalence in prisonsWith some exceptions, and unlike the picture for othercommunicable diseases in this setting, HCV infectionappears to show a relatively consistent epidemiologicalpicture in prisons around the world, despite cleardifferences in political and socio-cultural contexts. Instudies of prison populations in the United Kingdom(UK) and the Republic of Ireland, the prevalence of HCVantibodyranged from 8% to 37%. Prevalences weremuch higher in those reporting a history of injecting druguse (IDU), ranging up to 81%. 27, 31-33 In the United States(US), between 23% and 41% of prisoners were HCVantibodypositive. 36-43 Those reporting IDU history hadthe highest prevalences (up to 96.6% in one study 38 ) andmost studies, in the US and elsewhere, also reportedthat females were more likely to be infected than maleprisoners.A study in Canada found 33% of prisoners wereHCV-antibody positive, representing an increase onthe prevalence noted in an earlier study in the sameinstitution (28%). 20 In Brazil 41% of the incarceratedpopulation were estimated to be HCV-infected – 87%in those reporting IDU. 45 HCV prevalence in prisonersreporting IDU in Spain and Greece were 92% and 81%respectively. 46, 47 Similar findings have been reported inDanish and Italian prisoners. 48In Australia, Butler et al 49 found that 37% of male prisonentrants to a New South Wales (NSW) prison were HCVantibodypositive, as were 66% of those reporting IDUand 48% of those with tattoos. In a later study of maleand female NSW prisoners, Butler et al 50 estimated 39%overall and 67% of female prisoners were HCV-antibodypositive. Crofts et al 51 found that 39% of Victorianprisoners were found to be HCV-antibody positive in asmaller sample of Victorian inmates who injected (n=51).Crofts et al later found an HCV-antibody prevalence of88%. 13 Very high HCV prevalences have subsequentlybeen identified in male and female Victorian prisoners(55% and 67% respectively), 22 and a recent surveyconducted among prisoners entering seven prisons inNSW, Western Australia, Tasmania and Queensland,reported an overall prevalence of 35%. 52HCV transmission in prisonsOnly very few studies of HCV transmission have beenpublished in Australia or worldwide. Typically, studiesemploying serial testing for HCV-antibody have foundsurprisingly low transmission rates in the prisonpopulations studied. For instance, two US studies reportrates between 0.4 and 1.1 new cases per 100 personyears*, having observed as low as only two new casesover 12 to 24 months of follow-up. 40, 41 In another USstudy in ‘recidivist’ female prisoners (defined as thoseentering prison more than once during the two yearstudy period), Macalino et al 42 estimated a relativelyhigh transmission rate of 18.2 per 100 person years.The authors point out, however, it was not possibleto attribute these cases to prison exposure since allof these women spent time outside prison during thestudy period.Crofts et al 51 calculated a transmission rate of 18.3 per100 person-years in Victorian prisoners. Unfortunately itwas not possible to determine whether these were alltransmitted in prison, as all ten cases had spent at leastsome time outside of prison during the period of followup.Butler et al 55 compared the results of two prisonentrant surveys conducted five years apart in NSWand noted 16 new HCV cases among 90 initially HCVnegative prisoners who had participated in both surveys.Six of these cases had been continuously incarceratedbetween surveys, giving a transmission rate of 4.5 per100 person years. In another study that did not reportthe overall person time at risk, four seroconversionswere also noted amongst 29 IDU-reporting prisoners inNSW who were followed up over 14 months. 56The only other published Australian studies examiningtransmission within the prison setting were casestudies. Haber et al 24 describe four cases of newlyacquired HCV-infection within a prison in NSW attributedto injecting drugs, lacerations sustained during a physicalassault and during a hair cut with barber shears. Post etal 21 describe another NSW case attributed to tattooing inprison.In summary, although direct evidence of HCVtransmission in prison exists, it has so far proven verydifficult to study in this setting and there is still noclear picture of the rate at which it might be occurring.Relatively small sample sizes and short observationperiods, losses to follow up in those serving shortersentences and multiple prisoner admissions andtransfers are examples of some of the inevitable (andpossibly insurmountable) problems which may impacton the ability of studies to investigate HCV transmissionin prison populations.The South Australian HCV in Prisons StudyWhile there have been some high quality Australianstudies on HCV in prisons, there has been no previouswork on the situation in South Australia (SA). The SAstudy has been underway for approximately 18 monthsand is being conducted by the Discipline of PublicHealth, University of Adelaide, in conjunction withvarious stakeholders. The study is being conductedthroughout the correctional system in SA and involves alleight publicly operated adult prison sites (representingapproximately 93% of the state’s incarcerated* Person years are calculated by summing all the years each population member spent at risk of infection (i.e. in prison). For example, if one new HCV casewas noted in two prisoners who had spent a combined period of 5 years in prison the transmission rate would be 1 in 5 years, or 20 per 100 person years.17
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