HIV type 2 pathogenicity is not related to subtype in rural Guinea Bissau

Data from an MRC case-control study in rural Guinea Bissau suggest older H1V-2 carriers (aged 55 to 80 years) appear, over a period of 2 years, to have a mortality similar to that of uninfected controls, whereas in HIV-2 carriers under the age of 55 there is a significantly higher mortality, compared with uninfected controls. Genotyping of viruses from both groups revealed only subtype a to be circulating. Thus, although putative nonpathogenic HIV-2 subtypes have been described in patients from West Africa, these do not appear to be contributing significantly to the nonpathogenic clinical phenotype in this population.; HIV-2 infection is endemic in Guinea Bissau, with up to 20% of the population, depending upon age, infected. HIV-2 genetic subtypes A-E have been identified, although only subtypes A and B have been associated with clinical disease. Gambia's MRC Laboratories set up a prospective cohort study in 1991 to follow HIV-2-seropositive individuals in a rural village in Guinea Bissau, together with age- and sex-matched controls. Over a two-year mean follow-up period, 5.5% of HIV-2-infected subjects died compared to 1.8% of seronegative controls. The excess mortality among HIV-2 carriers is the result of deaths among infected individuals under age 55 years who have a significantly higher mortality relative to uninfected controls. HIV-2 carriers aged 55-80 years appeared to have mortality similar to that of uninfected controls. Genotyping of viruses from both groups found only subtype A to be circulating.