Cholera

IVI cholera model

Lead modeller: Jong-Hoon Kim

Institution(s): International Vaccine Institute (IVI)

Brief description of model:

The model utilizes a static framework to estimate the impact of the typhoid conjugate vaccine on various health outcomes, including the number of cases, deaths, years of life lost (YLLs), and disability-adjusted life years (DALYs). The impact of the vaccine is evaluated by first calculating the reduction in cases through vaccination and deaths, YLLS, DALYs were derived from the reduced number of cases. The model incorporates both the direct effects of vaccination on individuals who receive the vaccine and the indirect effects on the wider community through herd immunity. It accounts for vaccination strategies that may involve one or two doses, noting that not all individuals receiving the first dose complete the series with a second dose. The model adjusts for expected changes in annual incidence, which generally improve with advancements in water quality, sanitation, and hygiene. The parameters of the model, such as case distribution by severity, illness duration, vaccine coverage, and the demographics of the target population, is frequently updated to reflect the latest research. The impact of vaccine was explored over a broad spectrum of values for uncertain parameters.

Key publication(s):

Kim JH, Mogasale V, Burgess C, Wierzba TF. Impact of oral cholera vaccines in cholera-endemic countries: A mathematical modeling study. Vaccine. 2016 Apr 19;34(18):2113-20. doi: 10.1016/j.vaccine.2016.03.004. Epub 2016 Mar 15. PMID: 26993337.

Model code (where available):

https://github.com/kimfinale/cholera_typhoid_vimc_ivi

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JHU cholera model

Lead modeller: Elizabeth Lee

Link to all modelling group members

Institution(s): Johns Hopkins University (JHU)

Brief description of model:

This phenomenological model estimates annual cases, DALYS, and deaths averted for mass oral cholera vaccination (OCV) campaigns under different geographic targeting strategies. Model inputs include baseline estimates of cholera mean annual incidence, meta-analysis estimates of cholera vaccine efficacy over time, and indirect vaccine protection estimates from re-analyses of vaccine trials in India and Bangladesh

Key publication(s):

Lee, EC., Azman, AS., Kaminsky, J., Moore, S.M., McKay, H.S., Lessler, J. (2019) The projected impact of geographic targeting of oral cholera vaccination in sub-Saharan Africa: A modeling study PLOS Medicine 11 Dec 2019.

Model code (where available):