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What is HIV - 2?

The Less Common Cousin of HIV-1


Updated May 27, 2014

Three years after the emergence of AIDS, two scientists; Robert Gallo and Luc Montagnier found what they believed to be the viral cause of the new disease; HIV-1. Several years later, a new strain of HIV was found in a man living in Africa. They called the new strain HIV-2.

Profile - Robert Gallo MD

Profile - Luc Montagnier MD

What is HIV-2?

In biology, a strain is a variety of a specific organism. Similarities exist between strains but the small differences between them is what makes each a separate strain from the other. HIV-2 is a less common strain of HIV than is the more common HIV-1 strain. As much as they are alike they have subtle differences.

The HIV Life Cycle

How are HIV-1 and HIV-2 Similar?

Being the same virus, there are many similarities between HIV-1 and HIV-2. These similarities include:

How are HIV-1 and HIV-2 Different?

There are many differences between HIV-1 and HIV-2. They include:

  • HIV-2 seems to weaken the immune system more slowly than HIV-1

    What Does HIV Do To Your Body?

  • those people with HIV-2 are less infectious early in the course of the disease compared to those people with HIV-1

    Understandin Acute HIV

  • HIV-2 seems to be more infectious later in the course of disease when compared to HIV-1

  • HIV-2 occurs in different parts of the world compared to HIV-1

    Worldwide HIV Statistics

  • there is no FDA licensed viral load test for HIV-2 and the viral load test used for HIV-1 is not reliable for HIV-2

    What is Viral Load Testing

Where in the World is HIV-2 Most Common?

HIV-2 is highly concentrated in West Africa countries such as Senegal, Nigeria, Ghana, and the Ivory Coast. HIV-2 also spreads to other parts of the world but predominantly to those countries having strong ties to West Africa; France, Portugal, and Angola to name three. Very few cases are actually reported outside of these area but on occasion do surface because of international travel.

HIV Travel Requirements & Restrictions

Who's Most at Risk for HIV-2 Infection?

HIV-2 is transmitted in the same way as HIV-1. Certain people are, however, more at risk. They include:

  • people having unprotected sexual contact with partners from areas where HIV-2 is common

  • those having unprotected sex with someone diagnosed with HIV-2

  • people who share needles with HIV-2 positive people or with people from areas where HIV-2 is common

  • people who receive blood product transfusion in countries where HIV-2 is common

  • people receiving medication injections in countries where HIV-2 is common and sterile technique is not always used.

The Politics of Needle Exchange

Should I Be Tested For HIV-2?

HIV-2 testing is usually limited to those people who fit into one of the high risk populations discussed earlier. However, many HIV testing sites will perform an HIV-2 test as part of HIV testing if the HIV-1 ELISA and Western Blot tests are indeterminate (neither positive or negative) or positive.

What is HIV ELISA, Western Blot, and PCR Tests

If you feel you may fall into an HIV-2 risk category or you have traveled to areas where HIV-2 is prevalent (e.g. West Africa) talk with your doctor or test counselors at your local HIV testing agency.

de Cock, K. et. al:"Epidemiology and transmission of HIV-2: why there is no HIV-2 pandemic"; JAMA 270:17 pp 2083-2086, 1993.

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