Table 1.
Population, pathogen and response factors in the West African EVD outbreak (2014–2015) that contributed to major outbreak potential.
| Factor | West African EVD outbreak | Lessons for future outbreaks | |
|---|---|---|---|
| Population | Size | Three 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. | ||
| Pathogen | Infectivity | >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. | |
| Intervention | Diagnostics | >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.