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Predicting the Number of Cases from the Ebola Virus Disease Outbreak in Countries with Widespread and Intense Transmission

on Wed, 09/10/2014 - 05:25

[Updated: October 22nd, 2014]

This interactive data visualization shows the actual trends of cumulative number of cases and estimates for the next six weeks in the current Ebola virus disease outbreak, specifically considering Guinea, Liberia and Sierra Leone, countries with widespread and intense transmission.

Offical data reported by national health authorities to the World Health Organization (WHO) and published in WHO Disease outbreak news on Ebola virus disease and Situation report: Ebola response roadmap was aggregated by epidemiological weeks. Time series includes confirmed, probable and suspected cases by countries (Guinea, Liberia and Sierra Leoene) and all three countries together. Data set is being updated weekly once WHO publishes the Situation report.     .

Four independent predictive models based on exponential smoothing methods were fitted to the time series of cumulative cases of Ebola, one considering aggregated data from the three countries together and one for each specific country. Results are presented in the bellow data visualization. Hovering over the actual and estimate trend lines will provide information related to specific data point.

I hope this tool allows public health professionals, health managers, decision makers and policy makers involved in the Ebola virus disease outbreak in West Africa to plan and made informed decisions about needed resources and actions to control the epidemic.

In a further iteration of this tool, the prediction of deaths will be included.

As always, your comments, critics, suggestions and recommendations are welcome.

Other forecasting and projections of the current Ebola virus disease outbreak in West Africa 

Meltzer MI, Atkins CY, Santibanez S, et al. Estimating the future number of cases in the Ebola epidemic - Liberia and Sierra Leone, 2014 - 2015. Morbidity and Mortality Weekly Report. CDC. September 26th 2014. [Available online]

Washington ML, Atkins CY, Meltzer MI. Generic Ebola Response (ER): modeling the spread of disease impact and intervention. Version 2.5 [Software: Excel Spreadsheet] CDC Stacks.

WHO Ebola Response Team. Ebola Virus Disease in West Africa — The First 9 Months of the Epidemic and Forward Projections. The New England Journal of Medicine NEJM September 23, 2014 DOI: 10.1056/NEJMoa1411100 [Available online]

Francis Smart. 1.2 Millions Deaths by Ebola projected within Six Months? | Econometrics by Simulation

Maia Majunder.  Ebola Modeling update and Update: Ebola projections |  Mens et Manus

Chowell G, Nishiura H. Transmission dynamics and control of Ebola virus disease (EVD): A review. BioMedCentral Medicine 2014, 12:196. Published 10 October 2014 [Abstract, Provisional pdf]

A Camacho, A.J. Kucharski, S Funk, J Breman, P Piot, W.J. Edmunds. Potential for large outbreaks of Ebola virus disease. Epidemics. [Available online 6 Oct 2014]

Caitlin M. Rivers, Eric T. Lofgren, Madhav Marathe, et al. Modeling the Impact of Interventions of an Epidemic of Ebola in Sierra Leone and Liberia. PLOS Current Outbreaks. October 16, 2014 [Available online].

Jeffrey Shaman et al. Computer Model Predicts Growth of Ebola Infections in West Africa. (+ Data Visualization) Mailman School of Public Health. Columbia University.

David Fisman, Ashleigh Tuite. Projected Impact of vaccination Timing and Dose Availability on the Course of the 2014 West African Ebola Epidemic. PLOS Current Outbreak. Nov 21, 2014. [Available online

P.S. The forecast modeling work and data visualization of cases from Ebola virus disease in countries with widespread and intense transmission in West Africa were featured in the article "These Interactive Graphs Show What The Future Of The Ebola Outbreak May Look" published in The World Post/The Huffington Post on September 26, 2014. 

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Carefix's picture

I have seen reports that the real rates are far higher than those reported by a factor of up to 3 or 4. As the health systems such as they are break down then this real rate factor (RRF) will likely increase. It would be interesting to see additional curves with estimates for the RRF included.

I note the October figures seem to be wrong as the total should add up to about 20,000.

Jayanth Devasundaram's picture

Does this include the "quarantine" performed on 50,000 people in the slum? Right there is a potential for raising the numbers rather rapidly..

martiner's picture

Hi Jayanth,

The data source used in the forecasting analysis is the number of cases and deaths that national authorities from Guinea, Liberia and Sierra Leone are reporting to the World Health Organization (WHO). Disease outbreak news: Ebola virus disease and Ebola Situation Reports

T.F.'s picture

From the October 1 WHO situation update : "there remains compelling evidence obtained from responders and laboratory staff in the country that there is widespread under-reporting of new cases, and that the situation in Liberia, and in Monrovia in particular, continues to deteriorate." I read that as saying the data are unreliable; the fall in cases in Liberia may be more due to breakdown of the monitoring system as opposed to actual decrease in the rate of infection.

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