Potential for broad-scale transmission of Ebola virus disease during the West Africa crisis:lessons for the Global Health security agenda

Background:The 2014-2016 Ebola crisis in West Africa had approximately eight times as many reported deaths as the sum of all previous Ebola outbreaks.The outbreak magnitude and occurrence of multiple Ebola cases in at least seven countries beyond Liberia,Sierra Leone,and Guinea,hinted at the possibility of broad-scale transmission of Ebola.Main text:Using a modeling tool developed by the US Centers for Disease Control and Prevention during the Ebola outbreak,we estimated the number of Ebola cases that might have occurred had the disease spread beyond the three countries in West Africa to cities in other countries at high risk for disease transmission(based on late 2014 air travel patterns).We estimated Ebola cases in three scenarios:a delayed response,a Liberia-like response,and a fast response scenario.Based on our estimates of the number of Ebola cases that could have occurred had Ebola spread to other countries beyond the West African foci,we emphasize the need for improved levels of preparedness and response to public health threats,which is the goal of the Global Health Security Agenda.Our estimates suggest that Ebola could have potentially spread widely beyond the West Africa foci,had local and international health workers and organizations not committed to a major response effort.Our results underscore the importance of rapid detection and initiation of an effective,organized response,and the challenges faced by countries with limited public health systems.Actionable lessons for strengthening local public health systems in countries at high risk of disease transmission include increasing health personnel,bolstering primary and critical healthcare facilities,developing public health infrastructure(e.g.laboratory capacity),and improving disease surveillance.With stronger local public health systems infectious disease outbreaks would still occur,but their rapid escalation would be considerably less likely,minimizing the impact of public health threats such as Ebola.Conclusions:The Ebola outbreak could have potentially spread to other countries,where limited public health surveillance and response capabilities may have resulted in additional foci.Health security requires robust local health systems that can rapidly detect and effectively respond to an infectious disease outbreak.

Resources needed for US CDC’s support to the response to post-epidemic clusters of Ebola in West Africa,2016

Background:West African countries Liberia,Sierra Leone,and Guinea experienced the largest and longest epidemic of Ebola virus disease from 2014 to 2016;after the epidemic was declared to be over,Liberia,Guinea,and Sierra Leone still experienced Ebola cases/clusters.The United States Centers for Disease Control and Prevention(US CDC)participated in the response efforts to the latter Ebola clusters,by assisting with case investigation,contact identification,and monitoring.This study aims to estimate the cost to the US CDC of responding to three different Ebola clusters after the end of the Ebola epidemic in 2015:i)Sierra Leone,Tonkolili(Jan 2016,2 Ebola cases,5 affected regions);ii)Guinea,Nzerekore(Mar-May 2016,10 Ebola cases,2 affected regions);iii)Liberia,Somali Drive(Mar 2016,3 Ebola cases,1 affected region).Main text:After interviewing team members that had participated in the response,we estimated total costs(expressed in 2016 US Dollars[USD]),where total costs correspond to travel costs,deployed personnel costs,costs to prepare for deployment,procurement and interagency collaboration costs,among others.We also estimated cost per cluster case(corresponding to the total costs divided by the total number of cluster cases);and cost per case-affected-region(equal to the total costs divided by the product of the number of cases times the number of regions affected).We found that the response cost varied sixteenfold between USD 113166 in Liberia and USD 1764271 in Guinea,where the main cost drivers were travel and personnel costs.The cost per cluster case varied tenfold between 37722 in Liberia(three cases)and USD 347226 in Sierra Leone,and the cost per case-affectedregion varied threefold between USD 37722 in Liberia and USD 88214 in Guinea.Conclusions:Costs vary with the characteristics of each cluster,with those spanning more regions and cases requiring more resources for case investigation and contact identification and monitoring.These data will assist policy makers plan for similar post-epidemic responses.