What is HIV disease?

We tend to think of "disease" in simple terms: infection equals illness. It's a little different with HIV since the virus can cause slow, subtle damage to the immune system long before an infected person will feel ill. Most health care providers use the term "HIV disease" to identify the variety of changes a person may experience, from initial infection to more advanced stages of serious, life–threatening illness. The term describes the medical condition of anyone infected with the virus, regardless of his or her symptoms.