2.1 What do rehabilitation professionals need to know about the stages of HIV infection?

When a person first becomes infected it is called viremia, a term used for all viral infections. During this initial phase, the virus replicates rapidly and people commonly experience flu-like symptoms (e.g. fever, fatigue, aching muscles, headache, and rash). Many of these symptoms can go unrecognized.

A person is most infectious during this phase.

Within the first 2 to 6 weeks, the CD4 count decreases rapidly as the virus attacks these cells.

After 6 to 8 weeks, antibodies are developed as part of the immune response (seroconversion) and the viral load (amount of HIV in the blood) drops.

HIV tests are designed to detect if these antibodies are present so a person will have a positive HIV test after seroconversion. Different tests also have different testing windows.^1,2

The antibodies for HIV are measurable within 3 months of initial infection for most people. During this time, people may not show any signs of being infected.

During the clinical latency phase, a person infected with HIV may be symptom free and unaware of their HIV status. This phase varies in length and depends on many factors including pre-existing health status, genetic factors, social determinants of health, and stress.

When the CD4 count drops below 200 cells/mm3, the immune system struggles to fight off the virus, the viral load increases and the body is susceptible to opportunistic infections and HIV-related illnesses.

If the person is not treated with HIV medications at this point (i.e., once the CD4 count has dropped below 200 cells/mm3), the natural history of HIV has shown high mortality levels within 2 to 3 years.

It is important to note, however, that most individuals with HIV can now have a life expectancy that is close to normal if they can access and adhere to lifelong antiretroviral therapy.¹

In advanced stages of HIV, a person may be diagnosed with Acquired Immunodeficiency Syndrome (AIDS).

AIDS is not a disease. AIDS is a category developed in 1993 by the U.S. Centers for Disease Control as a way of identifying advanced HIV progression.¹ A person is said to have AIDS if:

• they are HIV-positive, and
• their CD4 count is less than 200 cells/mm3, or
• they have one of the 26 clinical conditions that are considered to be AIDS-defining

Given advances in HIV care, the AIDS classification system is used less often.

Rehabilitation providers should focus on addressing the challenges (i.e., impairments, activity limitations, participation restrictions) resulting from HIV and/or HIV-related illnesses (which may or may not constitute “AIDS”). See Section 1.3 for further details.