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.

During the West African Ebola epidemic, many data on interventions were recorded at a local level by some of the numerous partners (e.g. non-governmental organizations (NGOs) and other organizations) involved in the response. For example, some data were collected on the number and capacity of hospitals over time [115] and these were used in a study modelling community transmission to assess the impact of increasing hospital bed capacity [116] . However, the decentralization of the response meant that intervention data were not systematically reported or collated and these data were not shared widely with the research community. A failure to report interventions centrally and systematically can make it difficult to disentangle a lack of intervention effect from a lack of intervention implementation. This can particularly be a problem when numerous groups coordinate their own efforts, making it impossible to draw firm conclusions about interventions. In the absence of detailed data on intervention efforts in West Africa, multiple studies have assessed the combined impact of all interventions in place, by comparing transmissibility in the early phase (with no intervention) to that in the later phases [87, 117] . However, this approach provides less compelling evidence of a causal effect and does not disentangle the impact of different interventions performed at the same time, and hence is less informative for future response planning.