Question

What causes a low CD4 count if someone is living with HIV?

9 October 2026. Related: All topics, CD4 and viral load, Southern Africa, Starting treatment.

Hi there, I was diagnosed last year and live in south Africa. I am doing ok but what causes a low CD4 count?

Answer

Answer: Simon Collins

Hi there

Lots of things can cause a low CD4 count, including different infections.

The main cause of a low CD4 count with HIV is not being on treatment.

The longer someone is HIV positive without treatment the lower the CD4 count drops.

After starting HIV treatment – called ART – viral load becomes undetectable and the CD4 count increases again.

Please see this link for more detailed information about CD4 counts and how to interpret results.