HIV is a retrovirus that infects the vital organs and cells of the human immune system. The virus progresses in the absence of antiretroviral therapy (ART) - a drug therapy that slows or prevents the growth of new HIV viruses.

The rate of virus progression varies widely between individuals and depends on many factors. These factors include;

1. The age of the patient,

2. The body's ability to defend against HIV

3. The access to healthcare

4. The existence of other infections

5. The infected person's genetic inheritance

6. Resistance to certain strains of HIV and more.

For the most part, the symptoms of HIV are the result of infections caused by bacteria, viruses, fungi, and/or parasites.

These conditions do not normally develop in individuals with healthy immune systems, which protect the body against infection.