Someone needs blood every 2 seconds in the United States. Nearly 21 million blood components are transfused every year. Everyday in the United States 36,000 units of blood, 7,000 units of platelets and 10,000 units of plasma are transfused. Chances that a person will get infected products are extremely low because of careful screening and use of technology. Chance of transmitting HIV infection is 1 in 1.5 million, Hepatitis C 1 in 1.1 million and Hepatitis B 1 in 282,000. Chances of non infectious complications are far more common than infectious complications.
Source: 1.Blood Facts and Statistics- American Red Cross 2. New England Journal of Medicine