those who met standards. The Centers for Disease Control and Prevention (CDC) has responsibility for surveillance, detection, and warning of potential public health risks within the blood supply. The National Institutes of Health (NIH) supports these efforts through fundamental research. During the 1950s and 1960s, blood shield laws were adopted by 47 states. These laws exempt blood and blood products from strict liability or implied warranty claims on the grounds that they are a service rather than a product. The laws were developed on the premise that given the inherently risky nature of blood and blood products, those providing them required protection if the blood system was to be a reliable resource.
As a whole, this system works effectively to supply the nation with necessary blood and blood products, and its quality control mechanisms check most human safety threats. The events of the early 1980s, however, revealed an important weakness in the system—in its ability to deal with a new threat that was characterized by substantial uncertainty. With intent to prepare the guardians of the blood supply for future threats concerning blood safety, the Department of Health and Human Services commissioned the Institute of Medicine to study the transmission of HIV through the blood supply. The Committee to Study HIV Transmission Through Blood and Blood Products undertook this assignment fully aware of the advantages and dangers of hindsight. Hindsight offers an opportunity to gain the understanding needed to confront the next threat to the blood supply. The danger of hindsight is unfairly finding fault with decisions that were made in the context of great uncertainty.
Starting with the identification of 26 homosexual men with opportunistic diseases in June 1981, the CDC's Morbidity and Mortality Weekly Report became the source for reports of the epidemic. By July 1982, enough cases had occurred with common symptomatology to name the new disease ''acquired immune deficiency syndrome" (AIDS). By January 1983, epidemiological evidence from CDC's investigations strongly suggested that blood and blood products transmitted the agent causing AIDS and that the disease could also be transmitted through intimate heterosexual contact. The conclusion that the AIDS agent was blood-borne was based on two findings. First, AIDS was occurring in transfusion recipients and individuals with hemophilia who had received AHF concentrate; these patients did not belong to any previously defined group at risk for contracting AIDS. Second, the epidemiologic pattern of AIDS was similar to hepatitis B, another blood-borne disease.