Abstract
The 2013-15 Ebola epidemic that primarily affected Guinea, Sierra Leone and Liberia has become the most devastating Ebola epidemic in history [1]. This unprecedented epidemic appears to have stemmed from a single spillover event in South Guinea in December 2013 and rapidly spread to neighboring Sierra Leone and Guinea in a matter of weeks. Here we employ a network-based transmission model to evaluate the potential impact of reactive ring-vaccination strategies in the context of the Ebola epidemic in West Africa. We model ring-based vaccination strategies that incorporate the radius of contacts that are vaccinated for each infectious individual, the time elapsed from individual infectiousness to vaccinating susceptible and exposed contacts, and the number of available vaccine doses. Our baseline spatial transmission model in which the ring vaccination strategy is investigated has been previously shown to capture Ebola-like epidemics characterized by an initial phase of sub-exponential epidemic growth. Here we also extend this baseline model to account for heterogeneous community transmission rates that may be defined as a scalable function of the distance between an infectious individual and each member of that individual’s community. Overall, our findings indicate that reactive ring-vaccination strategies can effectively mitigate established Ebola epidemics. Importantly, we studied scenarios with varying number of weeks elapsed between the onset of symptoms and the day contacts are vaccinated and found that it is still beneficial to vaccinate contacts after the infectious period has elapsed. Our results indicate that while it is beneficial to vaccinate members of the community, the probability of extinction is not very sensitive to which contacts in the community are vaccinated unless transmission varies very steeply on the network distance between individuals. Both of these observations underscore the fact that vaccination can be effective by reducing transmission at the community level.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Abbreviations
- EVD:
-
Ebola virus disease
References
Team WHOER: Ebola Virus Disease in West Africa - The First 9 Months of the Epidemic and Forward Projections. New Engl. J. Med. 371(16), 1481-1495, 22 Sep 2014
Chowell, G., Nishiura, H.: Transmission dynamics and control of Ebola virus disease (EVD): a review. BMC Med. 12(1), 196 (2014)
Ebola response roadmap - Situation report - 23 Sep 2015. http://apps.who.int/ebola/current-situation/ebola-situation-report-23-september-2015. Accessed 27 Sep 2015
Baize, S., Pannetier, D., Oestereich, L., Rieger, T., Koivogui, L., Magassouba, N., et al.: Emergence of Zaire Ebola virus disease in Guinea–preliminary report. New Engl. J. Med. 371(15), 1418–1425 (2014)
Chowell, G., Nishiura, H.: Characterizing the transmission dynamics and control of Ebola virus disease. PLoS Biol. 13(1), e1002057 (2015)
Nishiura, H., Chowell, G.: Early transmission dynamics of Ebola virus disease (EVD), West Africa, March to August 2014. Euro surveillance: bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin, vol. 19, no. 36 (2014)
Althaus, C.L.: Estimating the reproduction number of Zaire ebolavirus (EBOV) during the 2014 outbreak in West Africa. PLOS Curr. Outbreaks Ed. 1. doi:10.1371/currents.outbreaks.91afb5e0f279e7f29e7056095255b288 (2014)
Fisman, D., Khoo, E., Tuite, A.: Early epidemic dynamics of the West African 2014 Ebola outbreak: estimates derived with a simple two-parameter model. PLoS Curr. 6 (2014)
Towers, S., Patterson-Lomba, O., Castillo-Chavez, C.: Temporal variations in the effective reproduction number of the 2014 West Africa Ebola outbreak. PLOS Curr. Outbreaks (2014)
Camacho, A., Kucharski, A., Aki-Sawyerr, Y., White, M.A., Flasche, S., Baguelin, M., et al.: Temporal changes in Ebola transmission in Sierra Leone and implications for control requirements: a real-time modelling study. PLoS Curr. 7 (2015)
Alizon, S., Lion, S., Murall, C.L., Abbate, J.L.: Quantifying the epidemic spread of Ebola virus (EBOV) in Sierra Leone using phylodynamics. Virulence 5(8), 825–827 (2014)
Volz, E., Pond, S.: Phylodynamic analysis of Ebola virus in the 2014 Sierra Leone epidemic. PLoS Curr. 6 (2014)
Pandey, A., Atkins, K.E., Medlock, J., Wenzel, N., Townsend, J.P., Childs, J.E., et al.: Strategies for containing Ebola in West Africa. Science 346(6212), 991–995 (2014)
Yamin, D., Gertler, S., Ndeffo-Mbah, M.L., Skrip, L.A., Fallah, M., Nyenswah, T.G., et al.: Effect of Ebola progression on transmission and control in Liberia. Ann. Intern. Med. 162, 11–17 (2014)
Meltzer, M.I., Atkins, C.Y., Santibanez, S., Knust, B., Petersen, B.W., Ervin, E.D., et al.: Estimating the future number of cases in the Ebola epidemic - Liberia and Sierra Leone. Morb. Mortal. Wkly. Rep. Surveill. Summ. 26(63), 1–14 (2014)
Lewnard, J.A., Ndeffo Mbah, M.L., Alfaro-Murillo, J.A., Altice, F.L., Bawo, L., Nyenswah, T.G., et al.: Dynamics and control of Ebola virus transmission in Montserrado, Liberia: a mathematical modelling analysis. Lancet Infect. Dis. 14(12), 1189–1195 (2014)
Merler, S., Ajelli, M., Fumanelli, L., Gomes, M.F., Piontti, A.P., Rossi, L., et al.: Spatiotemporal spread of the 2014 outbreak of Ebola virus disease in Liberia and the effectiveness of non-pharmaceutical interventions: a computational modelling analysis. Lancet Infect. Dis. 15(2), 204–211 (2015)
Rivers, C.M., Lofgren, E.T., Marathe, M., Eubank, S., Lewis, B.L.: Modeling the impact of interventions on an epidemic of Ebola in Sierra Leone and Liberia. PLoS Curr 6 (2014)
Scarpino, S.V., Iamarino, A., Wells, C., Yamin, D., Ndeffo-Mbah, M., Wenzel, N.S., et al.: Epidemiological and viral genomic sequence analysis of the 2014 Ebola outbreak reveals clustered transmission. Clin. Infect. Dis. An official publication of the Infectious Diseases Society of America 60(7), 1079–1082 (2015)
Drake, J.M., Kaul, R.B., Alexander, L.W., O’Regan, S.M., Kramer, A.M., Pulliam, J.T., et al.: Ebola cases and health system demand in Liberia. PLoS Biol. 13(1), e1002056 (2015)
Fasina, F., Shittu, A., Lazarus, D., Tomori, O., Simonsen, L., Viboud, C., et al.: Transmission dynamics and control of Ebola virus disease outbreak in Nigeria, July to September 2014. Euro surveillance: bulletin Europeen sur les maladies transmissibles = European communicable disease bulletin, vol. 19, no. 40 (2014)
Webb, G., Browne, C., Huo, X., Seydi, O., Seydi, M., Magal, P.: A model of the: Ebola epidemic in West Africa with contact tracing. PLoS Curr. 7 (2014)
Browne, C., Gulbudak, H., Webb, G.: Modeling contact tracing in outbreaks with application to Ebola. J. Theor. Biol. 7(384), 33–49 (2015)
Gomes, M.F., Piontti, A.P., Rossi, L., Chao, D., Longini, I., Halloran, M.E., et al.: Assessing the international spreading risk associated with the 2014 West African Ebola outbreak. PLOS Curr. Outbreaks (2014)
Bogoch, I.I., Creatore, M.I., Cetron, M.S., Brownstein, J.S., Pesik, N., Miniota, J., et al.: Assessment of the potential for international dissemination of Ebola virus via commercial air travel during the 2014 West African outbreak. The Lancet (2014)
Bellan, S.E., Pulliam, J.R.C., Pearson, C.A.B., Champredon, D., Fox, S.J., Skrip, L., et al.: The statistical power and validity of Ebola vaccine trials in Sierra Leone: a simulation study of trial design and analysis. Lancet Infect. Dis. 15(6), 703–710 (2015)
Cooper, B.S., Boni, M.F., Pan-ngum, W., Day, N.P., Horby, P.W., Olliaro, P., et al.: Evaluating clinical trial designs for investigational treatments of Ebola virus disease. PLoS Med. 12(4), e1001815 (2015)
Henao-Restrepo, A.M., Longini, I.M., Egger, M., Dean, N.E., Edmunds, W.J., Camacho, A., et al.: Efficacy and effectiveness of an rVSV-vectored vaccine expressing Ebola surface glycoprotein: interim results from the Guinea ring vaccination cluster-randomised trial. Lancet 386(9996), 857–866 (2015)
Greenhalgh, D.: Optimal control of an epidemic by ring vaccination. Commun. Stat. Stoch. Models 2(3), 339–363 (1986)
Muller, J., Schonfisch, B., Kirkilionis, M.: Ring vaccination. J. Math. Biol. 41(2), 143–171 (2000)
Kretzschmar, M., van den Hof, S., Wallinga, J., van Wijngaarden, J.: Ring vaccination and smallpox control. Emerg. Infect. Dis. 10(5), 832–841 (2004)
Tildesley, M.J., Savill, N.J., Shaw, D.J., Deardon, R., Brooks, S.P., Woolhouse, M.E., et al.: Optimal reactive vaccination strategies for a foot-and-mouth outbreak in the UK. Nature 440(7080), 83–86 (2006)
Ferguson, N.M., Donnelly, C.A., Anderson, R.M.: The foot-and-mouth epidemic in Great Britain: pattern of spread and impact of interventions. Science 292(5519), 1155–1160 (2001)
Kiskowski, M.: Three-scale network model for the early growth dynamics of 2014 West Africa Ebola epidemic. PLOS Curr. Outbreaks (2014). doi:10.1371/currents.outbreaks.b4690859d91684da963dc40e00f3da81
Kiskowski, M., Chowell, G.: Modeling household and community transmission of Ebola virus disease: epidemic growth, spatial dynamics and insights for epidemic control. Virulence 20, 1–11 (2015)
Chowell, G., Viboud, C., Hyman, J.M., Simonsen, L.: The Western Africa Ebola virus disease epidemic exhibits both global exponential and local polynomial growth rates. PLoS Curr. 7 (2015)
Wells, C., Yamin, D., Ndeffo-Mbah, M.L., Wenzel, N., Gaffney, S.G., Townsend, J.P., et al.: Harnessing case isolation and ring vaccination to control Ebola. PLoS Negl. Trop. Dis. 9(5), e0003794 (2015)
Anderson, R.M., May, R.M.: Infectious Diseases of Humans. Oxford University Press, Oxford (1991)
Hethcote, H.W.: The mathematics of infectious diseases. SIAM Rev. 42(4), 599–653 (2000)
Sattenspiel, L., Dietz, K.: A structured epidemic model incorporating geographic mobility among regions. Math. Biosci. 128(1–2), 71–91 (1995)
Newman, M.E.: Spread of epidemic disease on networks. Phys. Rev. E Stat. Nonlinear Soft Matter Phys. 66(1 Pt 2), 016128 (2002)
Watts, D.J., Strogatz, S.H.: Collective dynamics of ‘small-world’ networks. Nature 393(6684), 440–442 (1998)
Xu, Z., Zu, Z., Zheng, T., Zhang, W., Xu, Q., Liu, J.: Comparative analysis of the effectiveness of three immunization strategies in controlling disease outbreaks in realistic social networks. PloS One 9(5), e95911 (2014)
Pastor-Satorras, R., Vespignani, A.: Immunization of complex networks. Phys. Rev. E Stat. Nonlinear Soft Matter Phys. 65(3 Pt 2A), 036104 (2002)
Author information
Authors and Affiliations
Corresponding authors
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2016 Springer International Publishing Switzerland
About this chapter
Cite this chapter
Chowell, G., Kiskowski, M. (2016). Modeling Ring-Vaccination Strategies to Control Ebola Virus Disease Epidemics. In: Chowell, G., Hyman, J. (eds) Mathematical and Statistical Modeling for Emerging and Re-emerging Infectious Diseases. Springer, Cham. https://doi.org/10.1007/978-3-319-40413-4_6
Download citation
DOI: https://doi.org/10.1007/978-3-319-40413-4_6
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-40411-0
Online ISBN: 978-3-319-40413-4
eBook Packages: Mathematics and StatisticsMathematics and Statistics (R0)