2.2 What do rehabilitation providers need to know about CD4 count and viral load?

Cells in a person’s body with CD4 receptors on their surface are the primary targets destroyed by HIV.

CD4 count is the most important surrogate marker for health status and strongest predictor of disease progression.

How to interpret CD4 count:

• A normal CD4 count level is between 500 to 1500 cells/mm3.
• CD4 count in a healthy individual varies over
• In a person living with HIV, the CD4 count will become lower as their HIV disease
• Opportunistic infections are infections that occur more frequently and are more severe in people with weakened immune systems, including people with HIV.¹ Most opportunistic infections occur when a CD4 count is less than 200 cells/mm3.

The CD4 count is influenced by a number of factors (e.g., stress, illness, time at which it was measured) and therefore, the trend in CD4 counts is more important versus one test at a single point in time.

Viral load reflects the amount of virus (HIV) within the body. Viral load is used to predict the rate of progression of HIV disease and to initiate, monitor, and change antiretroviral therapy.

How to interpret viral load levels:

• The HIV viral load test measures the amount of HIV virus, in each ml or cubic centimeter of blood (e.g., from 50 to 500,000).
• The higher the viral load, the more viral reproduction (HIV copying itself) is taking place, and the more active (worse) the
• Viral load tests struggle to measure fewer than 50 HIV viruses in each ml of blood and so the test may say that the viral load is “undetectable.”

• This does not mean that a person is cured of
• It also does not mean that the patient should discontinue taking their
• An undetectable viral load does mean that a person’s HIV disease is well controlled (but not gone).
• There is now clear scientific evidence that “Undetectable = Untransmittable” (U=U) and there is a global campaign to spread this message from the HIV scientific community. Research has shown that effective ART prevents sexual transmission of HIV.¹

The goal of ART is to reduce viral load to the lowest possible level for the longest possible time.