oa Investigating the drivers of the hepatitis C virus epidemic in Egypt

Background: Egypt has by far the highest national-level hepatitis C virus (HCV) prevalence in the world, with more than 14% of the general population infected with the virus. The drivers of such epidemic are still not completely identified, with previous parenteral antischistosomal therapy (PAT) campaigns conducted throughout Egypt proposed as the major contributor of the high HCV prevalence. In an effort to clarify specific drivers of the HCV epidemic in Egypt, and to identify priority populations for HCV prevention interventions, we conducted a comprehensive statistical analysis and mapping of the spatial distribution of HCV infection across Egypt. Methods: We conducted statistical analysis of the world's largest cross-sectional study of HCV conducted by the Demographic and Health Survey in Egypt (EDHS) in 2008 including demographic, health, and HCV biomarker information for a sample of over 11,000 individuals aged 15-49 years. We also identified and compared spatial clusters with high numbers of HCV infections using Kulldorff spatial scan test. The test locates areas with higher numbers of HCV infections than expected under spatial randomness. For each identified cluster, a likelihood ratio test was computed. A P-value was determined through Monte Carlo simulations to evaluate the statistical significance of each cluster. Results: The analysis of the EDHS data indicated that only 9.1% of the population aged 15-59 was exposed to PAT; from this fraction, 28.6% are infected with HCV. These values suggest that PAT might be responsible for only about 8% of the total HCV infections in Egypt. Moreover, ever had a blood transfusion, ever had a dental treatment, and ever had a surgery significantly increased the odds of testing positive for HCV by 54%, 45%, and 28%, respectively. Our results also indicated substantial geographical clustering of HCV infections in Egypt. We identified settings with high HCV prevalence distributed in six geographical clusters located at the interface between the governorates of Beni Suef and Minya, Faiyum, Dakahlia, Kafr el-Sheikh, Monufia, and Minya. Conclusion: The small fraction of the population with previous exposure to PAT suggests that other modes of transmission fueled the HCV epidemic, and could be playing an essential role in the current spread of the HCV infection in Egypt. Our study provides direct evidence for strong geographic clustering of HCV infection in Egypt and locates priority geographic areas for spatially targeted interventions.