Predicting the extinction of HIV-2 in rural Guinea-Bissau.
Fryer HR., Van Tienen C., Van Der Loeff MS., Aaby P., Da Silva ZJ., Whittle H., Rowland-Jones SL., de Silva TI.
ObjectiveThis article predicts the future epidemiology of HIV-2 in Caió, a rural region of Guinea Bissau; and investigates whether HIV-2, which has halved in prevalence between 1990 and 2007 and is now almost absent in young adults in Caió, can persist as an infection of the elderly.DesignA mathematical model of the spread of HIV-2 was tailored to the epidemic in Caió, a village in Guinea-Bissau.MethodsAn age-stratified difference equation model of HIV-2 transmission was fitted to age-stratified HIV-2 incidence and prevalence data from surveys conducted in Caió in 1990, 1997 and 2007. A stochastic version of the same model was used to make projections.ResultsHIV-2 infection is predicted to continue to rapidly decline in Caió such that new infections will cease and prevalence will reach low levels (e.g. below 0.1%) within a few decades. HIV-2 is not predicted to persist in the elderly.ConclusionHIV-2 is predicted go extinct in Caió during the second half of this century.