HIV infects a type of white blood cell in the body’s immune system called a T-helper cell (also called a CD4 cell). These vital cells keep us healthy by fighting off infections and diseases.

HIV cannot grow or reproduce on its own. Instead, the virus attaches itself to a T-helper cell and fuses with it. It then takes control of the cell’s DNA, replicates itself inside the cell, and finally releases more HIV into the blood – continuing the multiplication process. This is the HIV lifecycle.

In this way, HIV weakens the body’s natural defences and over time severely damages the immune system. How quickly the virus develops depends on a person’s general health, how soon after getting HIV they’re diagnosed and start antiretroviral treatment, and how consistently they take their treatment.