Key data for outbreak evaluation: building on the Ebola experience

Cori, Anne; Donnelly, Christl A.; Dorigatti, Ilaria; Ferguson, Neil M.; Fraser, Christophe; Garske, Tini; Jombart, Thibaut; Nedjati-Gilani, Gemma; Nouvellet, Pierre; Riley, Steven; Van Kerkhove, Maria D.; Mills, Harriet L.; Blake, Isobel M.

In summary, the enormous quantity of detailed data collected during the West African Ebola epidemic played an invaluable role in guiding response efforts. However, several analyses could not be performed. Early on, severity, transmissibility and delay distributions were quantified and short-term projections were made, based on the case line-list and/or contact tracing data [3, 5, 7] . Some heterogeneity in severity and transmissibility could be identified (e.g. by age and viraemia [7, 10, 116, 125, [130] [131] [132] ), but other types of heterogeneity could not be assessed. For example, it was not possible to compare the CFR between hospitalized and non-hospitalized cases, because of biases in the way cases were recorded in the line-list [28] . Long-term projections were extremely challenging due to large uncertainty in population sizes, behaviour changes and changing intervention efforts. In addition, the relative risk of Ebola acquisition for HCWs was difficult to estimate due to the absence of reliable spatio-temporal data on the number of HCWs. Finally, systematic evaluation of interventions was not feasible due to multiple control measures being carried out at the same time, with little central recording of details of each intervention.