HIV-2 – not a global pandemic, but still causing challenges for diagnosis and treatment

Editor’s notes: HIV-2 is discussed much less than HIV-1 because it has not caused a global pandemic.  Nonetheless there are around 1-2 million people thought to be living with HIV-2, predominantly in West Africa and in Portugal and her historical connections (Brazil, Angola, Mozambique and India).  A useful review by de Mendoza C and colleagues from Spain highlights key features in the epidemiology, management and future directions for HIV-2.  The diagnosis is easy to miss and should be considered whenever routine HIV-1 tests give curious serological profiles.  There are also important differences when treating people living with HIV-2. HIV-2 cannot be treated with non-nucleoside reverse transcriptase inhibitors and some protease inhibitors do not work either. Viral load monitoring has not been commercialized, and so is often unreliable.  CD4 cell counts tend to drop more rapidly in HIV-1 and this has sometimes led to the suggestion that HIV-2 is a benign infection.  However, progression to an AIDS-like syndrome does occur, particularly in people who acquired HIV at a younger age.  The CD4 cell count recovery on antiretroviral therapy seem to be less effective in HIV-2 compared to HIV-1 infections. Failure and selection of drug resistance may be more frequent in HIV-2.

HIV-2 Epidemic in Spain - challenges and missing opportunities.

de Mendoza C, Cabezas T, Caballero E, Requena S, Amengual MJ, Peñaranda M, Sáez A, Tellez R, Lozano AB, Treviño A, Ramos JM, Pérez JL, Barreiro P, Soriano V; Spanish HIV-2 Network. AIDS. 2017 Mar 29. doi: 10.1097/QAD.0000000000001485. [Epub ahead of print]

HIV type 2 (HIV-2) is a neglected virus despite estimates of 1-2 million people infected worldwide. HIV-2 is less efficiently transmitted than HIV-1 by sex and from mother-to-child. Although AIDS may develop in HIV-2 carriers, it takes longer than in HIV-1-infected patients. In contrast with HIV-1 infection, there is no global pandemic caused by HIV-2, remaining the virus largely confined to West Africa. In a less extent and due to socioeconomic ties and wars, HIV-2 is prevalent in Portugal and its former colonies in Brazil, India, Mozambique and Angola. Globally, HIV-2 infections are steadily declining over time. A total of 338 cases of HIV-2 infection had been reported at the Spanish HIV-2 registry until December 2016, of whom 63% were male. Overall 72% were sub-Saharan Africans whereas 16% were native Spaniards. Dual HIV-1 and HIV-2 coinfection was found in 9% of patients. Heterosexual contact was the most likely route of HIV-2 acquisition in more than 90% of cases. Roughly one third presented with CD4 counts <200 cells/μL and/or AIDS clinical events. Plasma HIV-2 RNA was undetectable at baseline in 40% of patients. To date, one third of HIV-2 carriers have received antiretroviral therapy, using integrase inhibitors 32 individuals. New diagnoses of HIV-2 in Spain have remained stable since 2010 with an average of 15 cases yearly. Illegal immigration from Northwestern African borders accounts for over 75% of new HIV-2 diagnoses. Given the relatively large community of West Africans already living in Spain and the continuous flux of immigration from endemic regions, HIV-2 infection either alone or as coinfection with HIV-1 should be excluded once in all HIV-seroreactive persons, especially when showing atypical HIV serological profiles, immunovirological disconnect (CD4 count loss despite undetectable HIV-1 viremia) and/or high epidemiological risks (birth in or sex partners from endemic regions).

Abstract access 

Basic science, HIV
Europe
Spain
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