HIV2

HIV-2, or human immunodeficiency virus type 2, is a retrovirus in the lentivirus family that infects humans. It is distinct from HIV-1 and generally causes a slower progression to Acquired Immunodeficiency Syndrome (AIDS). HIV-2 is most common in West Africa and in communities with ties to that region, but it has spread to other areas through migration.

HIV-2 likely originated from simian immunodeficiency viruses circulating in sooty mangabeys and entered humans in multiple cross-species transmission events. The virus is categorized into several groups (A through H), with groups A and B responsible for most human infections. Compared with HIV-1, HIV-2 is less efficiently transmitted through sexual contact and blood; perinatal transmission is also less common. Disease progression tends to be slower, and untreated HIV-2 infection may maintain higher CD4 counts for longer, but it can still result in AIDS without treatment.

Diagnosis relies on HIV-1/2 discriminatory testing to distinguish HIV-2 infection from HIV-1. Some HIV tests that detect only HIV-1 may miss HIV-2. HIV-2 RNA testing and viral load measurements are used in cases where discrimination is unclear. Antiretroviral therapy (ART) for HIV-2 differs from HIV-1 in drug susceptibility: most non-nucleoside reverse transcriptase inhibitors (NNRTIs) are ineffective against HIV-2, while nucleoside reverse transcriptase inhibitors, certain protease inhibitors (often boosted), and integrase inhibitors are active. Common regimens include combinations of NRTIs with a boosted protease inhibitor or an integrase inhibitor.

Public health guidance emphasizes accurate diagnosis, appropriate ART regimens, and monitoring for treatment response. While HIV-2 remains less prevalent globally, awareness is important because its treatment requires different drug choices than HIV-1 to achieve viral suppression and improved long-term outcomes.