title: Prevalence and incidence of HIV-1 and HIV-2 before, during and after a civil war in an occupational cohort in Guinea-Bissau, West Africa.
abstract: OBJECTIVE
  To study prevalence and incidence of HIV-1 and HIV-2 between 1990 and 2007 and to examine impact of the civil war in 1998-1999. We also wanted to investigate possible interaction between HIV-1 and HIV-2.
  
  
  METHODS
  Open prospective cohort study of 4592 police officers in Guinea-Bissau, West Africa.
  
  
  METHODS
  Analysis of HIV-1 and HIV-2 prevalence and incidence divided in 2-3 years time strata.
  
  
  RESULTS
  HIV-1 prevalence (including HIV-1/HIV-2 dual reactivity) increased gradually from 0.6 to 3.6% before the war and was 9.5% in the first serosurvey after the war. HIV-1 incidence more than doubled during and shortly after the war, from 0.50 to 1.22 per 100 person-years. Both prevalence and incidence of HIV-1 decreased in the following periods after the war. HIV-2 prevalence decreased from 13.4 to 6.2% during the entire study period and HIV-2 incidence decreased from 1.38 to 0.18 per 100 person-years. Adjusted incidence rate ratios of HIV-1 incidence in HIV-2-positive participants compared with HIV-negative participants ranged from 1.02 to 1.18 (not significant) depending on the confounding variables included.
  
  
  CONCLUSIONS
  HIV-1 has increased, whereas HIV-2 has decreased and the risk of acquiring HIV-1 is now more than four times higher as compared with HIV-2. The civil war in 1998-1999 appears to have induced a temporary increase in HIV-1 transmission, but now a stabilization of HIV-1 incidence and prevalence seems to have taken place. There was no evidence of a protective effect of HIV-2 against HIV-1 infection.
authors.affiliation: Department of Clinical Sciences, Infectious Diseases Research Unit, Lund University, Malmö, Sweden.
authors.forename: Fredrik
authors.initials: F
authors.lastname: Månsson
authors.forename: Antonio
authors.initials: A
authors.lastname: Biague
authors.forename: Zacarias José
authors.initials: ZJ
authors.lastname: da Silva
authors.forename: Francisco
authors.initials: F
authors.lastname: Dias
authors.forename: L A Fredrik
authors.initials: LA
authors.lastname: Nilsson
authors.forename: Sören
authors.initials: S
authors.lastname: Andersson
authors.forename: Eva Maria
authors.initials: EM
authors.lastname: Fenyö
authors.forename: Hans
authors.initials: H
authors.lastname: Norrgren
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D004812:Epidemiologic Methods; D005260:Female; D006169:Guinea-Bissau / Q000453:epidemiology; D015658:HIV Infections / Q000453:epidemiology* / Q000635:transmission / Q000821:virology; D015497:HIV-1; D015498:HIV-2; D006801:Humans; D008297:Male; D008875:Middle Aged; D016495:Police / Q000706:statistics & numerical data; D014857:Warfare; D055815:Young Adult