- The amount of virus present (the viral load). A lot of virus leads to rapid progression of the disease.
- The amount of damage to the immune system (the degree of immunosuppression). The greater the damage (the lower the CD4 percentage), the faster the disease progresses.
- The nutritional status of the child. Poor nutrition results in a worse outcome as it lowers the number of CD4 cells.
- The number of HIV related infections. These co-infections (e.g. TB) may further depress the immune system and accelerate the course of HIV infection.
- Access to health care. Children die sooner if they do not have access to good health care as early diagnosis and treatment of infections is essential.
- Access to antiretroviral treatment.
- The amount of organ damage done before antiretroviral treatment is started.
The genetic make up of the child and the type of the virus are probably also important. The viral load during the asymptomatic phase of HIV infection (viral set point) determines how fast the HIV infection will progress.