Blood borne infections are those in which the infectious agent is transmitted from one person to another in contaminated blood. Infections of the blood can occur as a result of the spread of an ongoing infection, such as with bacteria including bacteria such as Yersinia pestis, Haemophilus influenzae, Staphylococcus aureus, and Streptococcus pyogenes. However, the latter re considered to be separate from true blood-borne infections.

Bacterial blood borne infection can occur, typically in the transfusion of blood. Such infections arise from the contamination of the site of transfusion. While information on the rate of such infections is scarce, the risk of transmission of bacterial infections via transfusions is thought to be at least equal to the risk of viral infection. For example, figures from the United States Food and Drug Administration indicate that bacterial infections comprise at least 10% of transfusion-related deaths in the United...