Infection and Response Practice Test 2026 - Free Practice Questions and Study Guide

AIDS is the stage of HIV infection where the immune system is severely damaged, so the body cannot effectively defend itself against infections or cancers. HIV attacks CD4+ T cells, and as their numbers fall, the immune defenses weaken, allowing opportunistic infections and some cancers to take hold. When this level of immune collapse occurs or when specific infections/cancers appear, the condition is diagnosed as AIDS. This is why describing AIDS as a severely damaged immune system unable to fight infections or cancers is the accurate depiction. It isn’t a mild immune deficiency, a skin condition, or a bacterial infection.