Table 1.

Population, pathogen and response factors in the West African EVD outbreak (2014–2015) that contributed to major outbreak potential.

FactorWest African EVD outbreakLessons for future outbreaks
PopulationSizeThree countries affected rapidly >Complacency about infections typically affecting marginalised or rural areas is misguided.
High transmission in large cities (Conakry, Freetown and Monrovia) dramatically increased case numbers. >Early interventions in an outbreak should target densely populated areas.
Vulnerability > Poor routine healthcare provision, water and sanitation in affected areas. > High-risk countries and communities should be targeted for preventative measures, including densely populated areas and informal settlements with poor infrastructure, eg refugee camps.
>Cultural factors including burial practices increased risk. > Improved understanding of sociocultural determinants of infectious disease transmission and implementation of interventions is required for vulnerable populations.
>Political agendas may have interfered with case reporting and investigation. >International agencies should oversee case ascertainment. Areas of political instability and conflict are likely to be at high risk.
PathogenInfectivity >Low infectious dose. Persistence of infectivity postmortem. >Target carers and healthcare workers with infection prevention and control education and interventions. Equip hospitals and clinics with permanent isolation facilities and provide regular training.
>Infections with respiratory and/or asymptomatic transmission likely to be very difficult to control.
Transmissibility >Production of copious body fluids during symptomatic stage increased transmissibility and put healthcare workers at particular risk.
Virulence >Severe disease in most cases. Likely few asymptomatic cases. Mortality extremely high.
Unknowns >Reservoir of Ebolavirus not well understood. Immune response not well characterised. >Consider infections where reservoir, mechanism of transmission and incubation period incompletely understood to be particularly high risk.
InterventionDiagnostics >Required complex, laboratory infrastructure, no bedside test available. >Rapid diagnostics should be prioritized for EVD and other pathogens with outbreak potential.
Vaccine >Not available >Prioritise study of pathogens with high outbreak potential and/or morbidity for funding and pre-clinical study.
Specific treatments >Not available >Knowledge sharing of interventions in the pipeline. Establish gaps. Develop global forum to form a consensus on research methods applicable for future outbreaks.
  • EVD = Ebola virus disease.