Survey of Inhibitors in Plasma-Product Exposed Toddlers

Inclusion Criteria: * Male subjects * Any ethnicity * Age \<6 years * Severe haemophilia A (FVIII:C \<1%), as confirmed at enrolment by the central laboratory. o Those patients diagnosed locally as severe but subsequently found to have FVIII levels \>= 1% on testing at the central laboratory will be separately recorded in the screening list. * Previously untreated (0 EDs to any FVIII concentrates or blood products) or minimally treated (\<5 EDs) with blood components, namely whole blood, fresh frozen plasma, packed red blood cells, platelets or cryoprecipitate. o Patients not meeting these criteria will be separately recorded in the screening list. * Negative inhibitor measurement at both local and central laboratory at screening * Ability to comply with study requirements * Signed informed consent of legal tutors o Patients who will not accept to enter into the study or to be randomized will be separately recorded. Exclusion Criteria: * Previous history of FVIII inhibitor * Other congenital or acquired bleeding defects * Plasma FVIII level \>= 1%, as assayed at the central laboratory o Those patients originally diagnosed locally as severe but subsequently found to have FVIII levels ranging from 1% to 2% on testing at the central laboratory will be separately recorded in the screening list. * Concomitant congenital or acquired immunodeficiency * Concomitant treatment with systemic immunosuppressive drugs * Concomitant treatment with any investigational drug