Pediatric and Liver Unit, Meyer Children's University-Hospital of Florence, Viale Pieraccini, Firenze, Italy. firstname.lastname@example.org.
HCV infection is a major public health problem worldwide. Several studies reported that HCV infection might cluster in families or households. Horizontal intrafamilial transmission of the virus has been demonstrated previously. Whether horizontal transmission makes any significant contribution to the global burden of HCV infection is still controversial and data about epidemiology and routes of transmission are uncertain. The certain diagnosis of horizontal intrafamilial transmission of HCV is based on the simultaneous presence of specific laboratory criteria, the temporal association between intrafamilial exposure and infection and the exclusion of all the potential extrafamilial routes of transmission of the infection. This review summarizes the current knowledge of epidemiology, risk factors and molecular biology of horizontal intrafamilial transmission of HCV infection.