IS THE APPARENT OUTBREAK OF HEPATITIS-A IN BELGIAN HEMOPHILIACS DUE TO A LASS OF PREVIOUS PASSIVE-IMMUNITY

Several reports describing outbreaks of hepatitis A in hemophilia A pa tients transfused with solvent/detergent-treated factor VIII concentra tes have raised concern about possible transmission of hepatitis A by these concentrates. We recently witnessed such an outbreak of hepatiti s A in 6 hemophilia A patients; review of the clinical data did not di sclose any increased risk factor for community-acquired hepatitis A. A case-control study comparing the prevalence of anti-hepatitis A IgG a ntibodies in hemophiliacs and age-matched controls showed a lower sero prevalence in hemophiliacs. This might be due to passive protection ac quired through transfusion of the previously used immunoglobulin-conta ining cryoprecipitate. The outbreak of hepatitis A could be explained as a catch-up phenomenon linked to the loss of passive protection with the use of purer factor VIII concentrates.