title: Measuring the impact of Ebola control measures in Sierra Leone.
abstract: Between September 2014 and February 2015, the number of Ebola virus disease (EVD) cases reported in Sierra Leone declined in many districts. During this period, a major international response was put in place, with thousands of treatment beds introduced alongside other infection control measures. However, assessing the impact of the response is challenging, as several factors could have influenced the decline in infections, including behavior changes and other community interventions. We developed a mathematical model of EVD transmission, and measured how transmission changed over time in the 12 districts of Sierra Leone with sustained transmission between June 2014 and February 2015. We used the model to estimate how many cases were averted as a result of the introduction of additional treatment beds in each area. Examining epidemic dynamics at the district level, we estimated that 56,600 (95% credible interval: 48,300-84,500) Ebola cases (both reported and unreported) were averted in Sierra Leone up to February 2, 2015 as a direct result of additional treatment beds being introduced. We also found that if beds had been introduced 1 month earlier, a further 12,500 cases could have been averted. Our results suggest the unprecedented local and international response led to a substantial decline in EVD transmission during 2014-2015. In particular, the introduction of beds had a direct impact on reducing EVD cases in Sierra Leone, although the effect varied considerably between districts.
authors.affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom adam.kucharski@lshtm.ac.uk.
authors.forename: Adam J
authors.initials: AJ
authors.lastname: Kucharski
authors.affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom.
authors.forename: Anton
authors.initials: A
authors.lastname: Camacho
authors.affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom.
authors.forename: Stefan
authors.initials: S
authors.lastname: Flasche
authors.affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom.
authors.forename: Rebecca E
authors.initials: RE
authors.lastname: Glover
authors.affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom.
authors.forename: W John
authors.initials: WJ
authors.lastname: Edmunds
authors.affiliation: Centre for the Mathematical Modelling of Infectious Diseases, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London WC1E 7HT, United Kingdom.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Funk
mesh_terms: D029043:Ebolavirus; D019142:Hemorrhagic Fever, Ebola / Q000453:epidemiology* / Q000635:transmission*; D006801:Humans; D008297:Male; D008954:Models, Biological; D012807:Sierra Leone
keywords: Ebola virus disease; Sierra Leone; control measures; mathematical model; treatment beds