|Blood Safety and HIV: UNAIDS Technical Update (UNAIDS, 1997, 8 p.)|
There are three principal factors which contribute to an unsafe blood supply, particularly with regard to HIV and other TTIs.
Lack of safe donors and unsafe blood donations
Paid donors are common in developing countries. They often come from the poorest sectors of society, and may be in poor health, undernourished and at risk of having TTIs. In some places, paid donors sell blood mainly to buy drugs to inject themselves with. This practice - if they share needles and syringes that are not sterilized - is in itself a high-risk activity for contracting HIV and other TTIs.
In addition, paid donors are likely to give blood more often than is recommended. This can be a considerable risk to the donor and will limit the benefit to the recipient.
Another type of donor is the replacement donor, or family replacement donor. In the replacement donor system, families of people needing a transfusion are asked to donate the same quantity as that given to their relative. This blood may be used directly, where compatible, or else placed in the blood bank. The relatives giving the blood are often hidden paid donors, and not related at all. Even if they are relatives, the normal criteria for selecting or deferring donors may not be strictly applied, so that the safety of their blood is in doubt.
The safest blood donor is the voluntary, unpaid donor. Such donors give blood out of altruism, and are not under pressure to donate blood. On the whole, they are more likely to meet national criteria for low-risk donors. And they are also more likely to be willing to donate blood on a regular basis and at properly-spaced intervals - subject to donor selection and deferral techniques. This is important for maintaining an adequate stock of safe blood.
Lack of screening
In many developing countries, blood is screened only in the main urban areas.
Lack of screening is most often the result of a lack of funding - because screening is often wrongly perceived as being expensive. Good organization, planning and management are also required, and these are equally difficult to find. Trained staff at all levels are likely to be lacking, as are test kits to screen blood.
Some countries that import blood products wish to test these for HIV and other infectious agents in order to validate the product.
However, this is neither necessary nor advisable. Blood products produced by reputable fractionators can generally be regarded as safe. There are two reasons for this. First, plasma or serum used in the preparation of plasma products will already have been screened before processing. Second, modern inactivation processes - used by all reputable fractionators - destroy HIV. Standard HIV and other antibody tests are designed for screening serum or plasma, not final blood products such as immunoglobulins, albumin and other plasma derivatives. The use of such assays on blood products will often give non-specific false-positive results.
Blood used inappropriately or incorrectly
Transfusions are not always necessary or appropriate. Minimizing unnecessary transfusions reduces the risk of transmitting HIV and other TTIs, especially in places where there is inadequate blood screening. Unnecessary transfusions also create an avoidable shortage in the blood supply - which encourages professional donors to become more active, in turn reducing the safety of the supply.