title: Assessment of yellow fever epidemic risk: an original multi-criteria modeling approach.
abstract: BACKGROUND
  Yellow fever (YF) virtually disappeared in francophone West African countries as a result of YF mass vaccination campaigns carried out between 1940 and 1953. However, because of the failure to continue mass vaccination campaigns, a resurgence of the deadly disease in many African countries began in the early 1980s. We developed an original modeling approach to assess YF epidemic risk (vulnerability) and to prioritize the populations to be vaccinated.
  
  
  RESULTS
  We chose a two-step assessment of vulnerability at district level consisting of a quantitative and qualitative assessment per country. Quantitative assessment starts with data collection on six risk factors: five risk factors associated with "exposure" to virus/vector and one with "susceptibility" of a district to YF epidemics. The multiple correspondence analysis (MCA) modeling method was specifically adapted to reduce the five exposure variables to one aggregated exposure indicator. Health districts were then projected onto a two-dimensional graph to define different levels of vulnerability. Districts are presented on risk maps for qualitative analysis in consensus groups, allowing the addition of factors, such as population migrations or vector density, that could not be included in MCA. The example of rural districts in Burkina Faso show five distinct clusters of risk profiles. Based on this assessment, 32 of 55 districts comprising over 7 million people were prioritized for preventive vaccination campaigns.
  
  
  CONCLUSIONS
  This assessment of yellow fever epidemic risk at the district level includes MCA modeling and consensus group modification. MCA provides a standardized way to reduce complexity. It supports an informed public health decision-making process that empowers local stakeholders through the consensus group. This original approach can be applied to any disease with documented risk factors.
authors: Epidemic and Pandemic Alert and Response, World Health Organization, Geneva, Switzerland. briands@who.int
authors: Sylvie
authors: S
authors: Briand
authors: Ariel
authors: A
authors: Beresniak
authors: Tim
authors: T
authors: Nguyen
authors: Tajoua
authors: T
authors: Yonli
authors: Gerard
authors: G
authors: Duru
authors: Chantal
authors: C
authors: Kambire
authors: William
authors: W
authors: Perea
mesh_terms: D002050:Burkina Faso / Q000453:epidemiology; D006801:Humans; D018570:Risk Assessment / Q000379:methods*; D012307:Risk Factors; D015004:Yellow Fever / Q000453:epidemiology* / Q000517:prevention & control*