Title

An SEIR Model of Potential Vaccination Program in the 2014 Sierra Leone Ebola Epidemic

Document Type

Presentation

Publication Date

1-22-2015

Abstract

The March 2014 Ebola outbreak in Sierra Leone and Liberia has significantly strained public health systems in both countries. Current epidemic models focus on non-vaccine treatment interventions. We modeled the potential consequences of future vaccine deployment in Sierra Leone, specifically the relationship between vaccination rates, date of commencement of a vaccination program, vaccine efficacy, and epidemic size. As a baseline model of the epidemic in the absence of control measures, we utilized a version of the SEIR (susceptible-exposed-infectious-recovered) epidemic model utilized by Chowell et al. to model Ebola outbreaks in the Congo parameterized using September 2014 estimates from the WHO. We utilized a model developed by Althaus using October 2014 epidemic data as a baseline for epidemic sizes in the presence of non-vaccination interventions. We plan to investigate whether the deployment of a moderately effective vaccine at a high vaccination rate can yield a similar reduction in deaths as a highly effective vaccine at a smaller vaccination rate.

Preliminary data utilizing the WHO baseline model, assuming the start of a vaccination program concurrent with the start of the epidemic in Sierra Leone, found that at a vaccine efficacy of 30%, a vaccination rate of 1000 individuals per day results in a 64% reduction of cases by November 2014. Data modeled using vaccination rates ranging from 1000 individual per day to 8000 individuals per day, vaccine efficacy values ranging from 30% to 70% efficacy, and various vaccination program commencement dates will be presented.

Sponsorship/Conference/Institution

Modeling the Spread of Ebola in West Africa Workshop

Location

Atlanta, GA

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