title: Harnessing case isolation and ring vaccination to control Ebola.
abstract: As a devastating Ebola outbreak in West Africa continues, non-pharmaceutical control measures including contact tracing, quarantine, and case isolation are being implemented. In addition, public health agencies are scaling up efforts to test and deploy candidate vaccines. Given the experimental nature and limited initial supplies of vaccines, a mass vaccination campaign might not be feasible. However, ring vaccination of likely case contacts could provide an effective alternative in distributing the vaccine. To evaluate ring vaccination as a strategy for eliminating Ebola, we developed a pair approximation model of Ebola transmission, parameterized by confirmed incidence data from June 2014 to January 2015 in Liberia and Sierra Leone. Our results suggest that if a combined intervention of case isolation and ring vaccination had been initiated in the early fall of 2014, up to an additional 126 cases in Liberia and 560 cases in Sierra Leone could have been averted beyond case isolation alone. The marginal benefit of ring vaccination is predicted to be greatest in settings where there are more contacts per individual, greater clustering among individuals, when contact tracing has low efficacy or vaccination confers post-exposure protection. In such settings, ring vaccination can avert up to an additional 8% of Ebola cases. Accordingly, ring vaccination is predicted to offer a moderately beneficial supplement to ongoing non-pharmaceutical Ebola control efforts.
authors.affiliation: Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Chad
authors.initials: C
authors.lastname: Wells
authors.affiliation: Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Dan
authors.initials: D
authors.lastname: Yamin
authors.affiliation: Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Martial L
authors.initials: ML
authors.lastname: Ndeffo-Mbah
authors.affiliation: Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Natasha
authors.initials: N
authors.lastname: Wenzel
authors.affiliation: Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Gaffney
authors.affiliation: Department of Biostatistics, Yale School of Public Health, New Haven, Connecticut, United States of America,; Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America,; Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America.
authors.forename: Jeffrey P
authors.initials: JP
authors.lastname: Townsend
authors.affiliation: Department of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America,; Santa Fe Institute, Santa Fe, New Mexico, United States of America.
authors.forename: Lauren Ancel
authors.initials: LA
authors.lastname: Meyers
authors.affiliation: Ministry of Health and Social Welfare, Monrovia, Liberia.
authors.forename: Mosoka
authors.initials: M
authors.lastname: Fallah
authors.affiliation: Ministry of Health and Social Welfare, Monrovia, Liberia.
authors.forename: Tolbert G
authors.initials: TG
authors.lastname: Nyenswah
authors.affiliation: Section of Infectious Diseases, Yale University School of Medicine, New Haven, Connecticut, United States of America,; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Frederick L
authors.initials: FL
authors.lastname: Altice
authors.affiliation: Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America,; Centre for Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Atkins
authors.affiliation: Center for Infectious Disease Modeling and Analysis, Yale School of Public Health, New Haven, Connecticut, United States of America,; Program in Computational Biology and Bioinformatics, Yale University, New Haven, Connecticut, United States of America,; Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, United States of America,; Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, Connecticut, United States of America.
authors.forename: Alison P
authors.initials: AP
authors.lastname: Galvani
mesh_terms: D004196:Disease Outbreaks / Q000517:prevention & control*; D029043:Ebolavirus / Q000276:immunology*; D019142:Hemorrhagic Fever, Ebola / Q000453:epidemiology / Q000517:prevention & control* / Q000635:transmission; D006801:Humans; D015994:Incidence; D007988:Liberia / Q000453:epidemiology; D008962:Models, Theoretical; D011634:Public Health; D012807:Sierra Leone / Q000453:epidemiology; D014611:Vaccination