How Common is Getting HIV from a Blood Transfusion?

According to estimates from the U.S. Centers for Disease Control, the current risk of becoming infected with the human immunodeficiency virus (HIV) from a blood transfusion as of 2011 is about one in two million in the United States. In total, about five million Americans actually receive donated blood each year, and the blood transfusion is considered to be a rare method of getting HIV. HIV is a virus that kills off cells necessary for preventing infections and diseases. Once the immune system has been destroyed, acquired immunodeficiency syndrome (AIDS) occurs. Since the infectious agent can be spread through donated blood, standards have been put into place to minimize the risk of getting HIV from a blood transfusion.

Although the history of AIDS can be traced back for some time, the epidemic was not identified until the early 1980s. Reports of obtaining HIV from a blood transfusion also began occurring at this time. With the recognition of these risks, mandatory changes in transfusion guidelines were made to lower risks of receiving contaminated blood.

The first step in giving blood is to complete a donor questionnaire that consists of a number of standardized questions. This questionnaire explores various criteria that may exclude someone from giving blood, including her lifestyle, travel to other regions of the world, and certain medical conditions. Those who are found to be in high-risk groups for having HIV or other infectious diseases are not allowed to donate blood to prevent the spread of HIV from a blood transfusion. High-risk individuals include prostitutes and those who have used such services within a year of attempting to donate blood. Additional high-risk groups include men who have ever had a same-sex encounter and intravenous drug users.

In addition to the HIV screening questionnaire, all blood centers do extensive testing on donated blood to ensure it is safe to use. Laboratory testing for HIV has been mandatory since 1985. One test detects antibodies that the immune system makes in response to the presence of HIV in the blood. Additional screenings were later added that can detect p24, a protein found within the actual virus. If tested blood comes up positive for HIV, the blood is destroyed, and the infected individual is informed and not allowed to donate blood again.

Laboratory tests for HIV are considered to be very accurate and continue to be refined to prevent HIV from a blood transfusion. There is still a brief period of time, however, in which donated blood that may be infected is not detected through current screening tests. This is usually due to an individual giving blood very soon after infection, generally within a few days. Even though this individual is already infected with HIV, the virus has not progressed to a point where it will trigger a positive test result.

Ultimately, the blood supply in the United States uses strict safety standards and is considered to be superior to most others in the world. Although receiving a transfusion is not completely risk free, the benefits of receiving the potentially lifesaving blood generally far outweigh the risks. Additionally, there is no risk associated with donating blood. Technicians routinely use disposable equipment each time blood is drawn, including a new sterilized needle and gloves. Individuals still concerned about the minor risk of getting HIV from a blood transfusion may be able to bank their own blood in advance of non-emergency surgeries or medical treatments.