Overview of HIV-2
HIV usually refers to the HIV-1 strain; but another strain, known as HIV-2, was first described in 1986 in West Africa. It is associated with the same opportunistic illnesses that result from HIV-1 infection; however, HIV-2 appears to have a milder and slower effect on the immune system. The mode of transmission is the same, although HIV-2 seems to be less transmissible from mother to child than HIV-1.
HIV-2 is predominantly restricted to West Africa, especially Cape Verde, Cote d'Ivoire (Ivory Coast), Gambia, Guinea-Bissau, Mali, Mauritania, Nigeria, and Sierra Leone. These nations reportedly have a higher than 1% prevalence rate in the general population, meaning that 1 out of every 100 people is infected with HIV-2. HIV-2 has spread through other West African nations, as well as outside of West Africa. Angola and Mozambique also have a higher than 1% prevalence rate. There are a very small number of HIV-2 cases in the United States, and testing for HIV-2 is not routinely done except in blood collection centers.
Risk Factors for HIV-2
According to the Centers for Disease Control and Prevention (CDC), the following factors increase the risk for contracting HIV-2:
- Having a sex partner from a country where HIV-2 is endemic
- Having a sex partner known to be infected with HIV-2
- Receiving a blood transfusion or nonsterile injection in a country where HIV-2 is endemic
- Sharing needles with an infected person or someone who is from a country where HIV-2 is endemic
- Being born to a mother with a risk factor or who has HIV-2 infection
Although the CDC does not recommend routine testing for HIV-2 in the United States, it is recommended that if a person who has any of the above risk factors is tested for HIV-1, he or she should also be tested for HIV-2. Blood donations are regularly tested for both HIV-1 and HIV-2.
Others who should be tested for HIV-2 include people who have AIDS-like symptoms but test negative for HIV-1 and people who have certain indeterminate HIV-1 test results.
Treatment for HIV-2
According to the CDC, it is not clear whether or to what extent the potential benefits of antiretroviral therapy outweigh the possible side effects regarding HIV-2. Laboratory studies suggest that nucleoside analogs are active against HIV-2, but are not as active as when fighting HIV-1.