A boy whose care was reviewed at Oxford was switched from cryoprecipitate to concentrates in 1976. Dr Rizza wrote to his referring haemophilia clinician advising to treat him with the N.H.S. concentrates and as a last resort it may be justified to put him onto one of the commercial Factor VIII concentrates. The reason for that recommendation was not specified and his parents were never told of any risk of infection associated with the use of factor concentrates.