title: Potential impact of reactive vaccination in controlling cholera outbreaks: an exploratory analysis using a Zimbabwean experience.
abstract: BACKGROUND
  To contain ongoing cholera outbreaks, the World Health Organization has suggested that reactive vaccination should be considered in addition to its previous control measures.
  
  
  OBJECTIVE
  To explore the potential impact of a hypothetical reactive oral cholera vaccination using the example of the recent large-scale cholera outbreak in Zimbabwe.
  
  
  METHODS
  This was a retrospective cost-effectiveness analysis calculating the health and economic burden of the cholera outbreak in Zimbabwe with and without reactive vaccination. The primary outcome measure was incremental cost per disability-adjusted life year (DALY) averted.
  
  
  RESULTS
  Under the base-case assumptions (assuming 50% coverage among individuals aged ≥2 years), reactive vaccination could have averted 1 320 deaths and 23 650 DALYs. Considering herd immunity, the corresponding values would have been 2 920 deaths and 52 360 DALYs averted. The total vaccination costs would have been ~$74 million and ~$21 million, respectively, with per-dose vaccine price of US$5 and $1. The incremental costs per DALY averted of reactive vaccination were $2 770 and $370, respectively, for vaccine price set at $5 and $1. Assuming herd immunity, the corresponding cost was $980 with vaccine price of $5, and the programme was cost-saving with a vaccine price of $1. Results were most sensitive to case-fatality rate, per-dose vaccine price, and the size of the outbreak.
  
  
  CONCLUSIONS
  Reactive vaccination has the potential to be a cost-effective measure to contain cholera outbreaks in countries at high risk. However, the feasibility of implementation should be further evaluated, and caution is warranted in extrapolating the findings to different settings in the absence of other in-depth studies.
authors.affiliation: Center for Health Decision Science, Department of Health Policy and Managemnt, Harvard School of Public Health, Boston, MA, USA. sunyoung.m.kim@gmail.com
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Kim
authors.forename: Yeongchull
authors.initials: Y
authors.lastname: Choi
authors.forename: Peter R
authors.initials: PR
authors.lastname: Mason
authors.forename: Simbarashe
authors.initials: S
authors.lastname: Rusakaniko
authors.forename: Sue J
authors.initials: SJ
authors.lastname: Goldie
mesh_terms: D002771:Cholera / Q000191:economics / Q000517:prevention & control*; D022121:Cholera Vaccines / Q000191:economics*; D003362:Cost-Benefit Analysis; D003661:Decision Support Techniques; D004196:Disease Outbreaks / Q000191:economics / Q000517:prevention & control*; D006801:Humans; D032521:Immunity, Herd; D014611:Vaccination / Q000191:economics / Q000379:methods*; D015030:Zimbabwe / Q000453:epidemiology
chemical_list: D022121:Cholera Vaccines