Acute hepatitis C virus (HCV) is typically defined as new viremia and antibody seroconversion.Rates and immunologic correlates of hepatitis C clearance have therefore been based on clearance of viremia only in individuals who initially had an antibody response. We sought to characterize the immunological correlates of clearance in patients with acute hepatitis C and their sexual contacts. We prospectively determined CD4؉ and CD8؉ cytotoxic T-lymphocyte responses in index patients with acute HCV and their sexual contacts who developed acute infection, either with or without spontaneous clearance, as well as those contacts who never developed viremia. Responses were measured using proliferation and ELISpot assays for CD4؉ and CD8؉ responses. We demonstrate in this prospective study that cellular immune responses can develop in exposed but persistently aviremic and antibody-negative individuals as well as those individuals with spontaneous clearance of acute HCV. These findings lend further credence to the importance of cellular immune responses in recovery from HCV and suggest that low exposure to HCV may lead to development of HCV-specific immune responses without ongoing HCV replication. This finding has important implications for HCV vaccine and therapeutic development.Hepatitis C virus (HCV) is a frequent cause of liver disease, leading to chronic infection in as many as 170 million persons worldwide. Vaccine development for HCV, like that for human immunodeficiency virus type 1 (HIV-1), is limited by the quasispecies nature of the virus as well as a lack of clear evidence that humoral immune responses protect against infection. Unlike patients with HIV-1, some individuals infected with acute hepatitis C can recover, although the asymptomatic nature of acute infection in most infected persons and the relative difficulty in conducting prospective studies have limited our understanding of the correlates of recovery from infection. Therefore, most studies have relied upon retrospective identification of subjects who previously cleared HCV to ascertain the correlates of protective immunity. These studies have shown that vigorous polyclonal cellular immune responses are associated with spontaneous recovery, whereas chronic infection is associated with a less vigorous immune response in the peripheral blood and liver (2,6,9,11,19,22,31). The only animal model of HCV infection, the chimpanzee, has provided additional valuable insights into the importance of both CD4 ϩ and CD8 ϩ responses in controlling infection (4,8,30). However, the small numbers of individuals who can be identified as having spontaneous recovery and the retrospective nature of such studies may underestimate the true rates of clearance.The major risk factor for transmission of HCV is percutaneous or parenteral exposure to infected blood or blood products. However, sexual transmission may play a role in some cases, although the exact extent to which this is true and the precise determinants of transmission are as yet unknown. In this study we took a...

Egypt has the highest prevalence of recorded hepatitis C virus (HCV) worldwide, estimated nationally at 14.7%, which is attributed to extensive iatrogenic transmission during the era of parenteral antischistosomal therapy (PAT) mass-treatment campaigns. The objective of our study was to attempt to highlight to what extent HCV transmission is ongoing and discuss the possible risk factors. We studied the prevalence of HCV among 7.8% of Egyptians resident in Qatar in relation to age, socioeconomic status, and PAT and discuss the possible risk factors. HCV testing was conducted in 2,335 participants, and results were positive for 13.5%, and 8.5% for those aged below 35 years. The prevalence of HCV in the PAT-positive population was 23.7% (123 of 518, 95% confidence interval [CI] 20.2%–27.6%) compared with 11.2% in the PAT-negative group. Significantly higher HCV prevalence occurred in participants who were older than 50 years (23%, 95% CI 19.3%–27.1%) compared to those aged 45–50 years (19.3%, 95% CI 15.2%–23.8%), 35–45 years (11.1%, 95% CI 8.9%–13.7%), and less than 35 years (8.5%, 95% CI 6.8%–10.4%) (P<0.0001). Insignificant higher prevalence occurred in the low socioeconomic group (14.2%, 95% CI 11.3%–17.4%). Logistic regression analysis revealed that increasing age, history of PAT, bilharziasis, and praziquantel were common risk factors, but there was no relation with dental care. Host genetic predisposition seems to be a plausible underlying factor for susceptibility among Egyptians and intense ongoing infection.