Background: Prophylaxis with von Willebrand factor is recommended in people with severe von Willebrand disease (VWD), regardless of age. WIL-31, the only prospective study with an on-demand run-in study as an intraindividual comparator, demonstrated the efficacy and safety of prophylaxis with the plasma-derived von Willebrand factor/
factor VIII concentrate wilate (Octapharma) in adults and children with VWD of all types. Prophylaxis is often considered in young children and adolescents with severe VWD and recurrent bleeding, although limited data support this strategy