|During the initial years of the AIDS epidemic a major effort was made to reduce the transmission of HIV associated with blood transfusions. These efforts focused on HIV antibody screening, blood donor selection, prevention of avoidable transfusions, blood banking and other measures.
Much of this work was actively supported by WHO/GPA. While efforts to guarantee an HIV-free blood supply are continuing, the dissolution of GPA contributed to blood safety issues slipping down on the agendas of resource-strapped countries and donors. This is especially problematic in sub-Saharan Africa. With both HIV prevalence and the number of blood transfusions high, the risk of transfusion-associated HIV transmission is highest in this area. In 1995, UNAIDS estimated that a quarter of the 2.3 million blood donations in sub-Saharan Africa were not screened for HIV.
Many of the transfusions given in sub-Saharan Africa are unnecessary, despite high levels of actual need for transfusions in populations where fertility is high and malaria and anaemia are common. In some hospitals, donors are not routinely screened for HIV risk, because they are relatives of the patients. Where blood screening policies are in place, implementation is often hindered by a lack of reagents, skilled staff, or equipment.
Many countries are now renewing their attention to this important and recently neglected area. They are trying to establish and enforce guidelines on blood safety, and are especially keen to ensure quality control.
Contaminated blood transfusion probably remains the greatest source of HIV infection in health care settings. But there are also risks of infection associated with other aspects of care. Health service providers may become infected with HIV through needle stick injuries and injuries during surgery. Poor caring practices by HIV-infected medical staff may also carry a risk of infection for the patient. And when injecting and other equipment is poorly sterilised, HIV may be carried from an HIV-infected to an uninfected patient in the health care setting. "Universal precautions" are designed to minimise these events, but irregular supplies of surgical gloves or sterile needles, poor sterilisation equipment and overburdened staff unable to follow time-consuming safety routines often contribute to the breach of these precautions.
|There are very few systematic indicators for any aspect of blood safety, from the screening of donors to the quality of existing HIV screening systems. Standardised prevention indicators in the area of blood safety are desperately needed, and need to include measures of donor screening and transfusion rates as well as the screening of blood units. It is worth noting, however, that in very high prevalence epidemics, for example, where more than one adult in five is HIV infected, the utility of donor screening policies is perhaps less useful. Resources may be better used for monitoring the quality of blood screening procedures. Indeed, the higher the population prevalence of HIV, the higher a priority blood safety should be for the national programme.
The lack of trained staff and other essential inputs such as reagents and reliable refrigeration are important constraints to maintaining a safe blood supply in many countries. It is safe to assume that these constraints will also apply to the ability to monitor and evaluate blood safety.
The monitoring of blood safety is much easier in countries where all blood for transfusion is collected by a centrally administered national blood transfusion service, or where all blood, regardless of its provenance, is screened in central laboratories. However such services are comparatively rare. Private blood banks are common in many countries, and in many cases, individual hospitals manage their own blood supplies. And many transfusions will take place in private hospitals or clinics, increasing the chances that records of the total number of transfusions may be incomplete. Donor screening and screening of blood units can vary substantially between services. This means that where universal quality control is not possible the sampling frame for facility-based monitoring and evaluation will be critical.