Subtypes of HIV

Human immunodeficiency viruses
Phylogenetic tree of the SIV and HIV viruses
Scientific classification
(unranked):	Virus
Realm:	Riboviria
Kingdom:	Pararnavirae
Phylum:	Artverviricota
Class:	Revtraviricetes
Order:	Ortervirales
Family:	Retroviridae
Subfamily:	Orthoretrovirinae
Genus:	Lentivirus
Groups included
Human immunodeficiency virus 1 Human immunodeficiency virus 2
Cladistically included but traditionally excluded taxa
Simian immunodeficiency virus (subgroups i, ii)[1]

The subtypes of HIV include two main subtypes, known as HIV type 1 (HIV-1) and HIV type 2 (HIV-2). These subtypes have distinct genetic differences and are associated with different epidemiological patterns and clinical characteristics.

HIV-1 exhibits a genetic relation to viruses indigenous to chimpanzees and gorillas that inhabit West Africa, while HIV-2 viruses are affiliated with viruses present in the sooty mangabey, a vulnerable West African primate.^[2]

HIV-1 viruses can be further stratified into groups M, N, O, and P. Among these, HIV-1 group M viruses are the most prevalent, infecting nearly 90% of people living with HIV and are responsible for the global AIDS pandemic. Group M can be further subdivided into subtypes based on genetic sequence data. Certain subtypes are known for their increased virulence or drug resistance to different medications used to treat HIV.

HIV-2 viruses are generally considered to be less virulent and less transmissible than HIV-1 M group viruses, although HIV-2 is also known to still cause AIDS.

One of the prevailing challenges in the pursuit of effective management of HIV is the virus's pronounced genetic variability and rapid viral evolution.^[3]