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Did You Know There Are Two Types of HIV?

May 22, 2026
HIV AIDS

Most people know that HIV is the virus that can lead to AIDS. Fewer realize that there are two main types of HIV: HIV-1 and HIV-2.

Both attack the immune system and, if left untreated, can progress to acquired immunodeficiency syndrome (AIDS). But they differ in where they are most commonly found, how easily they spread, how quickly they progress, and which medications are most effective in treating them. 

Origins

HIV-1 originated in the region surrounding the Congo Basin and is by far the most common type of HIV, accounting for approximately 95% of all infections worldwide. (Healthline)

HIV-2 originated in West Africa, where it remains most prevalent today. Cases outside the region are relatively uncommon—in the United States, HIV-2 is estimated to account for fewer than 1% of all HIV cases. Compared with HIV-1, HIV-2 is less easily transmitted and typically progresses more slowly. (HIV Curriculum)

Although HIV-2 is far less common, an estimated one to two million people worldwide are living with the virus, including some individuals who are co-infected with both HIV-1 and HIV-2. Current and accurate prevalence data are scarce, and because the two viruses infect the same immune cells, dual infection is possible. (HIV.gov)

Testing

HIV-1 and HIV-2 share only about 55% of their genetic sequence. Because of these differences, specialized tests are needed to accurately identify each type and ensure people receive the most appropriate treatment. (Healthline)

Treatment

Because HIV-2 is naturally resistant to certain medications commonly used to treat HIV-1, treatment approaches may differ depending on which type of virus a person has. Identifying the correct type of HIV is therefore essential to selecting the most effective combination of medications. (HIV.Gov)

With accurate diagnosis and effective treatment, people living with either HIV-1 or HIV-2 can live long, healthy lives. 

Differences Between HIV-1 and HIV-2

HIV-1HIV-2
More commonly found – 95% of all infectionsLess common 
Found worldwideMainly found in West Africa
Greater genetic diversity/subtypesLess diverse
Typically faster progressionUsually slower progression
Typically higher viral loadTypically lower viral load
Broad treatment optionsResistant to some HIV drugs