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Epidemiology, transmission, natural history, and pathogenesis of HIV-2 infection

Geoffrey S Gottlieb, MD, PhD
Section Editor
John A Bartlett, MD
Deputy Editor
Jennifer Mitty, MD, MPH


Although HIV-1 infection is associated with most of the global AIDS pandemic, HIV-2 is an important cause of disease in certain regions of the world where it is endemic. HIV-2 infection has also been described in pockets of locations globally, so it is an important consideration in patients with an AIDS-like illness [1].

This topic will address the epidemiology, transmission, natural history, and pathogenesis of HIV-2 infection. The clinical manifestations, diagnosis, and treatment of HIV-2 are discussed elsewhere. (See "Clinical manifestations and diagnosis of HIV-2 infection" and "Treatment of HIV-2 infection".)


As of 2015, the World Health Organization (WHO) estimates that approximately 36.7 million people are living with HIV/AIDS; by crude estimates, approximately one to two million of these people are infected with HIV-2 [2-4], including some who are dually infected with both viruses [2-7].

Origin of the epidemic — Serologic evidence of a second human immunodeficiency virus was first discovered in 1985 in Senegal [8] with subsequent isolation of HIV-2 documented in 1986 from a Cape Verdean patient [9]. Similar to HIV-1, HIV-2 was initially a zoonosis, originally transmitted from West African Sooty mangabeys to humans [10-12]. Serologic data suggest that HIV-2 may have been circulating as early as 1966 [13] while phylogenetic evidence dates its introduction into humans during the first half of the 20th century [14,15]. (See "Global epidemiology of HIV infection", section on 'Origin of the HIV epidemic'.)

HIV-2 in West Africa — HIV-2 is endemic in West Africa, although data over the past decade suggest that epidemiologic trends may be shifting [16-18]. Several African countries (eg, Senegal, Gambia, Cote D’Ivoire, Guinea-Bissau) have reported declining prevalence rates of HIV-2 over time [16-20].

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Literature review current through: Dec 2017. | This topic last updated: Sep 20, 2016.
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  1. Campbell-Yesufu OT, Gandhi RT. Update on human immunodeficiency virus (HIV)-2 infection. Clin Infect Dis 2011; 52:780.
  2. http://www.unaids.org/en/media/unaids/contentassets/documents/epidemiology/2013/gr2013/UNAIDS_Global_Report_2013_en.pdf (Accessed on May 23, 2014).
  3. http://www.cdc.gov/hiv/resources/factsheets/hiv2.htm (Accessed on March 01, 2011).
  4. Ariën KK, Abraha A, Quiñones-Mateu ME, et al. The replicative fitness of primary human immunodeficiency virus type 1 (HIV-1) group M, HIV-1 group O, and HIV-2 isolates. J Virol 2005; 79:8979.
  5. Cot MC, Poulain M, Delagneau JF, et al. Dual HIV-1 and HIV-2 infection in West Africa supported by synthetic peptide analysis. AIDS Res Hum Retroviruses 1988; 4:239.
  6. Evans LA, Moreau J, Odehouri K, et al. Simultaneous isolation of HIV-1 and HIV-2 from an AIDS patient. Lancet 1988; 2:1389.
  7. Rayfield M, De Cock K, Heyward W, et al. Mixed human immunodeficiency virus (HIV) infection in an individual: demonstration of both HIV type 1 and type 2 proviral sequences by using polymerase chain reaction. J Infect Dis 1988; 158:1170.
  8. Barin F, M'Boup S, Denis F, et al. Serological evidence for virus related to simian T-lymphotropic retrovirus III in residents of west Africa. Lancet 1985; 2:1387.
  9. Clavel F, Guétard D, Brun-Vézinet F, et al. Isolation of a new human retrovirus from West African patients with AIDS. Science 1986; 233:343.
  10. Gao F, Yue L, Robertson DL, et al. Genetic diversity of human immunodeficiency virus type 2: evidence for distinct sequence subtypes with differences in virus biology. J Virol 1994; 68:7433.
  11. Gao F, Bailes E, Robertson DL, et al. Origin of HIV-1 in the chimpanzee Pan troglodytes troglodytes. Nature 1999; 397:436.
  12. Gao F, Yue L, White AT, et al. Human infection by genetically diverse SIVSM-related HIV-2 in west Africa. Nature 1992; 358:495.
  13. Kawamura M, Yamazaki S, Ishikawa K, et al. HIV-2 in west Africa in 1966. Lancet 1989; 1:385.
  14. Lemey P, Pybus OG, Wang B, et al. Tracing the origin and history of the HIV-2 epidemic. Proc Natl Acad Sci U S A 2003; 100:6588.
  15. Wertheim JO, Worobey M. Dating the age of the SIV lineages that gave rise to HIV-1 and HIV-2. PLoS Comput Biol 2009; 5:e1000377.
  16. van der Loeff MF, Awasana AA, Sarge-Njie R, et al. Sixteen years of HIV surveillance in a West African research clinic reveals divergent epidemic trends of HIV-1 and HIV-2. Int J Epidemiol 2006; 35:1322.
  17. Eholié S, Anglaret X. Commentary: decline of HIV-2 prevalence in West Africa: good news or bad news? Int J Epidemiol 2006; 35:1329.
  18. da Silva ZJ, Oliveira I, Andersen A, et al. Changes in prevalence and incidence of HIV-1, HIV-2 and dual infections in urban areas of Bissau, Guinea-Bissau: is HIV-2 disappearing? AIDS 2008; 22:1195.
  19. Hamel DJ, Sankalé JL, Eisen G, et al. Twenty years of prospective molecular epidemiology in Senegal: changes in HIV diversity. AIDS Res Hum Retroviruses 2007; 23:1189.
  20. Fryer HR, Van Tienen C, Van Der Loeff MS, et al. Predicting the extinction of HIV-2 in rural Guinea-Bissau. AIDS 2015; 29:2479.
  21. Larsen O, da Silva Z, Sandström A, et al. Declining HIV-2 prevalence and incidence among men in a community study from Guinea-Bissau. AIDS 1998; 12:1707.
  22. Remy G. HIV-2 infection throughout the world. A geographical perspective. Sante 1998; 8:440.
  23. UNAIDS AIDS epidemic update 2006. In: Geneva, Switzerland: Joint United Nations Programme on HIV/AIDS (UNAIDS) and World Health Organization (WHO) 2004; 2006. p.1-94.
  24. Centers for Disease Control (CDC). AIDS due to HIV-2 infection--New Jersey. MMWR Morb Mortal Wkly Rep 1988; 37:33.
  25. Centers for Disease Control and Prevention (CDC). HIV-2 Infection Surveillance--United States, 1987-2009. MMWR Morb Mortal Wkly Rep 2011; 60:985.
  26. Torian LV, Eavey JJ, Punsalang AP, et al. HIV type 2 in New York City, 2000-2008. Clin Infect Dis 2010; 51:1334.
  27. Léonard G, Chaput A, Courgnaud V, et al. Characterization of dual HIV-1 and HIV-2 serological profiles by polymerase chain reaction. AIDS 1993; 7:1185.
  28. Walther-Jallow L, Andersson S, da Silva Z, Biberfeld G. High concordance between polymerase chain reaction and antibody testing of specimens from individuals dually infected with HIV types 1 and 2 in Guinea-Bissau, West Africa. AIDS Res Hum Retroviruses 1999; 15:957.
  29. Sarr AD, Hamel DJ, Thior I, et al. HIV-1 and HIV-2 dual infection: lack of HIV-2 provirus correlates with low CD4+ lymphocyte counts. AIDS 1998; 12:131.
  30. Ishikawa K, Fransen K, Ariyoshi K, et al. Improved detection of HIV-2 proviral DNA in dually seroreactive individuals by PCR. AIDS 1998; 12:1419.
  31. Travers K, Mboup S, Marlink R, et al. Natural protection against HIV-1 infection provided by HIV-2. Science 1995; 268:1612.
  32. Sarr AD, Sankalé JL, Hamel DJ, et al. Interaction with human immunodeficiency virus (HIV) type 2 predicts HIV type 1 genotype. Virology 2000; 268:402.
  33. Kokkotou EG, Sankale JL, Mani I, et al. In vitro correlates of HIV-2-mediated HIV-1 protection. Proc Natl Acad Sci U S A 2000; 97:6797.
  34. Günthard HF, Huber M, Kuster H, et al. HIV-1 superinfection in an HIV-2-infected woman with subsequent control of HIV-1 plasma viremia. Clin Infect Dis 2009; 48:e117.
  35. U.S. Public Health Service guidelines for testing and counseling blood and plasma donors for human immunodeficiency virus type 1 antigen. MMWR Recomm Rep 1996; 45:1.
  36. Meda N, Ndoye I, M'Boup S, et al. Low and stable HIV infection rates in Senegal: natural course of the epidemic or evidence for success of prevention? AIDS 1999; 13:1397.
  37. Schutz R, Savarit D, Kadjo JC, et al. Excluding blood donors at high risk of HIV infection in a west African city. BMJ 1993; 307:1517.
  38. Kanki PJ, Travers KU, MBoup S, et al. Slower heterosexual spread of HIV-2 than HIV-1. Lancet 1994; 343:943.
  39. Comparison of vertical human immunodeficiency virus type 2 and human immunodeficiency virus type 1 transmission in the French prospective cohort. The HIV Infection in Newborns French Collaborative Study Group. Pediatr Infect Dis J 1994; 13:502.
  40. Adjorlolo-Johnson G, De Cock KM, Ekpini E, et al. Prospective comparison of mother-to-child transmission of HIV-1 and HIV-2 in Abidjan, Ivory Coast. JAMA 1994; 272:462.
  41. Prazuck T, Yameogo JM, Heylinck B, et al. Mother-to-child transmission of human immunodeficiency virus type 1 and type 2 and dual infection: a cohort study in Banfora, Burkina Faso. Pediatr Infect Dis J 1995; 14:940.
  42. Gottlieb GS, Hawes SE, Agne HD, et al. Lower levels of HIV RNA in semen in HIV-2 compared with HIV-1 infection: implications for differences in transmission. AIDS 2006; 20:895.
  43. Burgard M, Jasseron C, Matheron S, et al. Mother-to-child transmission of HIV-2 infection from 1986 to 2007 in the ANRS French Perinatal Cohort EPF-CO1. Clin Infect Dis 2010; 51:833.
  44. O'Donovan D, Ariyoshi K, Milligan P, et al. Maternal plasma viral RNA levels determine marked differences in mother-to-child transmission rates of HIV-1 and HIV-2 in The Gambia. MRC/Gambia Government/University College London Medical School working group on mother-child transmission of HIV. AIDS 2000; 14:441.
  45. Hawes SE, Sow PS, Stern JE, et al. Lower levels of HIV-2 than HIV-1 in the female genital tract: correlates and longitudinal assessment of viral shedding. AIDS 2008; 22:2517.
  46. Simon F, Matheron S, Tamalet C, et al. Cellular and plasma viral load in patients infected with HIV-2. AIDS 1993; 7:1411.
  47. Marlink R, Kanki P, Thior I, et al. Reduced rate of disease development after HIV-2 infection as compared to HIV-1. Science 1994; 265:1587.
  48. Gottlieb GS, Sow PS, Hawes SE, et al. Equal plasma viral loads predict a similar rate of CD4+ T cell decline in human immunodeficiency virus (HIV) type 1- and HIV-2-infected individuals from Senegal, West Africa. J Infect Dis 2002; 185:905.
  49. Gilbert PB, McKeague IW, Eisen G, et al. Comparison of HIV-1 and HIV-2 infectivity from a prospective cohort study in Senegal. Stat Med 2003; 22:573.
  50. MacNeil A, Sarr AD, Sankalé JL, et al. Direct evidence of lower viral replication rates in vivo in human immunodeficiency virus type 2 (HIV-2) infection than in HIV-1 infection. J Virol 2007; 81:5325.
  51. Popper SJ, Sarr AD, Travers KU, et al. Lower human immunodeficiency virus (HIV) type 2 viral load reflects the difference in pathogenicity of HIV-1 and HIV-2. J Infect Dis 1999; 180:1116.
  52. Poulsen AG, Aaby P, Larsen O, et al. 9-year HIV-2-associated mortality in an urban community in Bissau, west Africa. Lancet 1997; 349:911.
  53. Martinez-Steele E, Awasana AA, Corrah T, et al. Is HIV-2- induced AIDS different from HIV-1-associated AIDS? Data from a West African clinic. AIDS 2007; 21:317.
  54. Schim van der Loeff MF, Jaffar S, Aveika AA, et al. Mortality of HIV-1, HIV-2 and HIV-1/HIV-2 dually infected patients in a clinic-based cohort in The Gambia. AIDS 2002; 16:1775.
  55. Sousa AE, Carneiro J, Meier-Schellersheim M, et al. CD4 T cell depletion is linked directly to immune activation in the pathogenesis of HIV-1 and HIV-2 but only indirectly to the viral load. J Immunol 2002; 169:3400.
  56. MacNeil A, Sankale JL, Meloni ST, et al. Long-term intrapatient viral evolution during HIV-2 infection. J Infect Dis 2007; 195:726.
  57. Andersson S, Norrgren H, da Silva Z, et al. Plasma viral load in HIV-1 and HIV-2 singly and dually infected individuals in Guinea-Bissau, West Africa: significantly lower plasma virus set point in HIV-2 infection than in HIV-1 infection. Arch Intern Med 2000; 160:3286.
  58. Leligdowicz A, Yindom LM, Onyango C, et al. Robust Gag-specific T cell responses characterize viremia control in HIV-2 infection. J Clin Invest 2007; 117:3067.
  59. Duvall MG, Jaye A, Dong T, et al. Maintenance of HIV-specific CD4+ T cell help distinguishes HIV-2 from HIV-1 infection. J Immunol 2006; 176:6973.
  60. Angin M, Wong G, Papagno L, et al. Preservation of Lymphopoietic Potential and Virus Suppressive Capacity by CD8+ T Cells in HIV-2-Infected Controllers. J Immunol 2016; 197:2787.
  61. Matheron S, Pueyo S, Damond F, et al. Factors associated with clinical progression in HIV-2 infected-patients: the French ANRS cohort. AIDS 2003; 17:2593.
  62. Nkengasong JN, Kestens L, Ghys PD, et al. Dual infection with human immunodeficiency virus type 1 and type 2: impact on HIV type 1 viral load and immune activation markers in HIV-seropositive female sex workers in Abidjan, Ivory Coast. AIDS Res Hum Retroviruses 2000; 16:1371.
  63. Greenberg AE. Possible protective effect of HIV-2 against incident HIV-1 infection: review of available epidemiological and in vitro data. AIDS 2001; 15:2319.
  64. Alabi AS, Jaffar S, Ariyoshi K, et al. Plasma viral load, CD4 cell percentage, HLA and survival of HIV-1, HIV-2, and dually infected Gambian patients. AIDS 2003; 17:1513.
  65. Koblavi-Dème S, Kestens L, Hanson D, et al. Differences in HIV-2 plasma viral load and immune activation in HIV-1 and HIV-2 dually infected persons and those infected with HIV-2 only in Abidjan, Côte D'Ivoire. AIDS 2004; 18:413.
  66. Borget MY, Diallo K, Adje-Toure C, et al. Virologic and immunologic responses to antiretroviral therapy among HIV-1 and HIV-2 dually infected patients: case reports from Abidjan, Côte d'Ivoire. J Clin Virol 2009; 45:72.
  67. Landman R, Damond F, Gerbe J, et al. Immunovirological and therapeutic follow-up of HIV-1/HIV-2-dually seropositive patients. AIDS 2009; 23:426.
  68. Esbjörnsson J, Månsson F, Kvist A, et al. Inhibition of HIV-1 disease progression by contemporaneous HIV-2 infection. N Engl J Med 2012; 367:224.
  69. van Tienen C, Schim van der Loeff M, Peterson I, et al. HTLV-1 and HIV-2 infection are associated with increased mortality in a rural West African community. PLoS One 2011; 6:e29026.
  70. Prince PD, Matser A, van Tienen C, et al. Mortality rates in people dually infected with HIV-1/2 and those infected with either HIV-1 or HIV-2: a systematic review and meta-analysis. AIDS 2014; 28:549.
  71. Esbjörnsson J, Månsson F, Kvist A, et al. Increased survival among HIV-1 and HIV-2 dual-infected individuals compared to HIV-1 single-infected individuals. AIDS 2014; 28:949.
  72. Brenchley JM, Price DA, Schacker TW, et al. Microbial translocation is a cause of systemic immune activation in chronic HIV infection. Nat Med 2006; 12:1365.
  73. Leligdowicz A, Feldmann J, Jaye A, et al. Direct relationship between virus load and systemic immune activation in HIV-2 infection. J Infect Dis 2010; 201:114.
  74. Levy JA. HIV pathogenesis: 25 years of progress and persistent challenges. AIDS 2009; 23:147.
  75. Ancuta P, Kamat A, Kunstman KJ, et al. Microbial translocation is associated with increased monocyte activation and dementia in AIDS patients. PLoS One 2008; 3:e2516.
  76. Redd AD, Dabitao D, Bream JH, et al. Microbial translocation, the innate cytokine response, and HIV-1 disease progression in Africa. Proc Natl Acad Sci U S A 2009; 106:6718.
  77. Michel P, Balde AT, Roussilhon C, et al. Reduced immune activation and T cell apoptosis in human immunodeficiency virus type 2 compared with type 1: correlation of T cell apoptosis with beta2 microglobulin concentration and disease evolution. J Infect Dis 2000; 181:64.
  78. Nowroozalizadeh S, Månsson F, da Silva Z, et al. Microbial translocation correlates with the severity of both HIV-1 and HIV-2 infections. J Infect Dis 2010; 201:1150.
  79. Hegedus A, Nyamweya S, Zhang Y, et al. Protection versus pathology in aviremic and high viral load HIV-2 infection-the pivotal role of immune activation and T-cell kinetics. J Infect Dis 2014; 210:752.
  80. Buggert M, Frederiksen J, Lund O, et al. CD4+ T cells with an activated and exhausted phenotype distinguish immunodeficiency during aviremic HIV-2 infection. AIDS 2016; 30:2415.