6533b7d3fe1ef96bd125ff64

RESEARCH PRODUCT

An Outbreak of Hepatitis C Virus Infection Among Transfused Thalassemia Patients: Root Cause Analysis, Phylogenetic Epidemiology and Antiviral Therapy

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Background: Occurrence of HCV infection is reduced by effective risk management procedures, but patient-to-patient transmission continues to be reported in healthcare settings. We report an outbreak of 11 patients with HCV acute hepatitis (seven new infections and four re-infections) among 128 thalassemia patients followed at a Hospital in Sicily. Methods All patients with acute hepatitis and known chronic infection were tested for HCV-RNA, HCV genotyping, and NS3, NS5A and NS5B HCV-genomic regions sequencing.  To identify transmission clusters we built phylogenetic trees for each gene employing Bayesian methods.  Findings All patients with acute hepatitis were infected with HCV genotype 1b. Root-cause analysis, including a lookback procedure, led us to exclude blood donors as the source of HCV transmission. The phylogenetic analysis, conducted on seven patients with acute infection and eight patients with chronic infection, highlighted four transmission clusters including at least one patient with chronic and one patient with acute HCV infection. All patients in the same cluster received a blood transfusion at the Thalassemia Unit during the same day. Two patients with acute hepatitis spontaneously cleared HCV within four weeks and nine patients received ledipasvir plus sofosbuvir for six weeks, all achieving a sustained virological response.  Interpretation Combined use of root cause analysis and molecular epidemiology was effective in ascertaining the origin of the HCV outbreak.  Antiviral therapy avoided the chronic progression of the infection and further spread in care units and in the family environment. Funding Regional Health System of Sicily and by the Italian Ministry of Health (RF-2016-02362422). Declaration of Interest: V.D.M received speaking and/or consulting fees by Abbvie, Gilead, MSD, Intercept. F.C-S. received speaking and/or consulting fees by Abbvie, Gilead, Janssen, Merck/MSD, ViiV . All other authors have nothing to declare. Ethical Approval: This study was conducted in agreement with the Helsinki Declaration. Since the available DAAs were not licensed for acute hepatitis, the regional health authorities and local ethics committee authorized DAA therapy in patients with diagnosis of acute hepatitis