AIDS and the safety and adequacy of the Canadian blood supply.

It is now just over three years since it became apparent that blood and blood product therapy carried with them the risk of infecting recipients with the then unknown causative agent of acquired immunodeficiency syndrome (AIDS). It was not long before the general public became aware of the risk of this possible means of transmission of the disease. Apprehension grew with the realization that effective action to ensure the safety of the blood supply from this threat was seriously limited by the fact that the causative agent was as yet unknown. By early 1983, these circumstances made it necessary in countries where the incidence of AIDS was recognized as epidemic to adopt empirical, epidemiologically-based donor screening measures in order to minimize the risk of receiving unsafe blood. The new and different approaches implemented as a result of this initiative included education of donors as to the various high-risk factors associated with development and/or transmission of AIDS. Those with these high-risk factors were informed of their obligation to exclude themselves from donating blood. These measures became operative in both the United States and Canada by March 1983. Given the psychological and sociological implications of such measures, it is to the credit of both the donors concerned and the blood collection and