Public Health and Communicable Diseases - SA Health - SA.Gov.au

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