Hepatitis: Micallef JM

Micallef JM, Kaldor JM, Dore GJ. · National Centre in HIV Epidemiology and Clinical Research, The University of New South Wales, Darlinghurst, Sydney, NSW, Australia. · J Viral Hepat. · Pubmed #16364080 No free full text.

Abstract: A large number of studies have reported on spontaneous viral clearance rates in acute hepatitis C infection, however most have been small, and reported rates have varied quite widely. To improve the precision of the estimated rate of spontaneous viral clearance, a systematic review was conducted of longitudinal studies. Factors associated with viral clearance were also examined. Inclusion criteria for studies were: longitudinal assessment from time of acute hepatitis C; hepatitis C virus RNA analysis as determinant of viral clearance; untreated for acute hepatitis C. Information on study population, and factors that may influence viral clearance were extracted from each study. Viral clearance was defined among individuals with at least 6 months follow-up following acute hepatitis C. The number of subjects with viral clearance was expressed as a proportion for each study and a weighted mean for proportion was calculated. A total of 31 studies were examined. Study populations included nine studies of post-transfusion hepatitis, 19 of acute clinical hepatitis, and three of sero-incident cases. In total, data was available for 675 subjects and the mean study population was 22 (range 4-67). The proportion with viral clearance ranged from 0.0 to 0.8, with a weighted mean of 0.26 (95% CI 0.22-0.29). Factors associated with viral clearance were female gender and acute clinical hepatitis C study population. Further studies are required to more clearly define predictors of clearance and guide therapeutic intervention strategies.

Micallef JM, Macdonald V, Jauncey M, Amin J, Rawlinson W, van Beek I, Kaldor JM, White PA, Dore GJ. · National Centre in HIV Epidemiology and Clinical Research, The University of New South Wales, Sydney, NSW, Australia. · J Viral Hepat. · Pubmed #17501762 No free full text.

Abstract: A retrospective cohort study was established of injecting drug users (IDUs) to assess evidence for hepatitis C virus (HCV) protective immunity through a comparison of incidence of initial HCV infection and HCV reinfection. Incidence of initial HCV infection was determined among HCV seronegative IDUs, and HCV reinfection determined among IDUs with newly acquired HCV infection, HCV viraemia and subsequent HCV RNA clearance. Serum was available for HCV RNA analysis from stored samples taken at the time of prior blood-borne virus screening. Potential HCV reinfection was defined as a positive HCV RNA following at least one negative HCV RNA. Incidence of initial HCV infection was 17/100 person-years (95% CI, 14-20/100 person-years). The incidence of potential HCV reinfection was 42/100 person-years (95% CI, 25-61/100 person-years), and after excluding cases without a change in HCV genotype and less than three consecutive HCV RNA negative assessment, incidence of reinfection was 31/100 person-years (95% CI, 17-62/100 person-years). Following adjustment for HCV risk behaviour variables the incidence rate ratio of HCV reinfection to initial infection was 1.11 (P = 0.8). Several cases of HCV reinfection appear to have developed persistent infection.

Jauncey M, Micallef JM, Gilmour S, Amin J, White PA, Rawlinson W, Kaldor JM, van Beek I, Dore GJ. · New South Wales Public Health Officer Training Program, New South Wales Department of Health, Kirketon Road Centre, South Eastern Sydney Area Health Service, Sydney, New South Wales, Australia. · J Infect Dis. · Pubmed #15346337 No free full text.

Abstract: A retrospective cohort of injection drug users with newly acquired hepatitis C virus (HCV) infection was established to examine viral clearance. Newly acquired HCV infection was defined by anti-HCV antibody seroconversion within a 2-year interval. Stored serum samples were tested for HCV RNA, with viral clearance defined as >/=2 consecutive negative HCV RNA test results after infection. Ninety-nine cases of HCV infection were identified; 57 had >/=2 HCV RNA test results after infection. Viral clearance occurred in 24 (42%) cases, with Kaplan-Meier estimated probabilities of 23%, 38%, and 40% at 6, 12, and 24 months, respectively.