Human immunodeficiency virus (HIV) is classified into two main types: HIV-1, which is closely related to a simian immunodeficiency virus (SIV) in chimpanzees, and HIV-2, which is closely related to an SIV in sooty mangabeys. HIV-2 is a minority HIV species; the exact prevalence is unknown but is estimated to be 1–2 million cases worldwide. Although endemic in West Africa, the distribution of HIV-2 is limited and low prevalence in most settings means that understanding and experience of HIV-2, relative to HIV-1, are often lacking. Since HIV-2 was first recognised, evidence has changed regarding pathogenicity and prognosis. Although HIV-2 was initially considered non-pathogenic, it is now known that most untreated individuals with HIV-2 will experience disease progression, albeit at a slower rate compared to HIV-1.
Diagnosis, monitoring and management of HIV-2 remain challenging. Antiretroviral drugs are mostly developed for activity against HIV-1, therefore many are inactive against HIV-2 and there are limited in vitro data for those drugs that may be used. To date, there have been no published randomised controlled trials of antiretroviral therapy for HIV-2 and understanding is based on cohort studies and observational data.
The overall purpose of these guidelines is to provide guidance on best clinical practice in the treatment and management of adults with HIV-2.
The guidelines were peer-reviewed by Professor Sarah L. Rowland-Jones, Universities of Oxford and Sheffield, and Dr Erasmus Smit, Institute of Environmental Science and Research, New Zealand.
The guidelines are scheduled for full review by October 2026.