The infection rate from a single unit of tainted blood was nearly 100 percent. This demonstrates how potent this virus is and the most efficient mode of transmission - blood to blood. Most of these patients have now died. Another extremely efficient way to get infected is by sharing HIV-contaminated and unsterilized needles or syringes, as in intravenous drug use where blood is often drawn up into the needle and syringe before the drug is infected. So far 50,000 of U.S. AIDS cases have occurred this way.
Needle sticks occur relatively frequently in a health care setting.
Five dental patients of one Florida dentist got HIV while he worked on their teeth. But no other medical or dental cases of transmission from health care worker to patient have been documented. In the U.S. about 3,000 babies have become HIV-infected through their infected mothers. This occurs before birth, during labor and delivery or through breast-feeding. Don't inject drugs and avoid other activities that bring an infected person's blood, semen or vaginal fluids into your body.