According to the Oregon Department of Education, HIV is not contracted through contact with dried blood. The department states that the virus starts dying as soon as it leaves the body, so when blood has dried, the virus is dead.
The Oregon Department of Education recommends treating a bodily fluid as potentially dangerous if it is still wet. The Centers for Disease Control and Prevention identifies specific ways HIV is transmitted between people. Forms of transmission include, but are not limited to, unprotected sex and sharing injection devices with someone who is HIV-positive. In addition, the CDC recognizes that HIV can pass along from mother to infant during pregnancy, birth or breastfeeding. The virus can also be transmitted through infected blood products or tissue transplants.