Table 3.
An overview of modelling studies of Ebola and study designs (Research aim: Trajectory prediction)
| References | Dataset/Factors | Description of Modelling Approaches | Compartments, if applicable | Assumption of population mixing, if applicable | Model fitting and calibration approach, if applicable | Sensitivity analysis, if applicable | Description of account for data bias, if applicable |
|---|---|---|---|---|---|---|---|
| Area et al. [43] | Case data from WHO [1] | Developed classical differential equations and fractional SEIR model to predict the outbreak trajectory | Susceptible–exposed–infectious–removed (SEIR) | Assumed homogeneous mixing | Fitted models with the real data and obtained parameters values using l^2 norm | NA | NA |
| Bellan et al. [44] | Unspecified | Compared the projections of two simple models (with and without asymptomatic infection) based on the Ebola epidemic in Liberia | NA | NA | NA | NA | Modelled scenarios that does not account for asymptomatic infections and account for the presence of asymoptomic infection |
| Dong et al. [45] | Case data from WHO [1] | Ebola case prediction was obtained by a SEIIRF model with the consideration of post-death and hospitalisation compartments | Susceptible–exposed–infected–recovered–hospitalised–buried (SEIIRHF) | Considered those who have died and are in the process of being buried and number of people in hospital who develop to first stage or second stage of infection | Fitted case prediction curve with real data both in total cases and death cases | NA | NA |
| Drake et al. [46] | Case data from WHO [1], Liberia Ministry of Health or United Nations Office for the Coordination of Humanitarian Affairs (UN-OCHA) | Developed a multi-type branching process model that incorporates key heterogeneities and time-varying parameters to mimic changing human behaviour and controls in Liberia. Focused on the numbers of new infections caused by each case considering offspring distributions | Two generations of infection in a multi-type branching process model | Accounted for subpopulation differences, including hospital treatment vs. community care, transmission at funerals, and scenario-dependent transmission risk differences during care-giving | Fitted ensemble model from plausible parameters with the case data in Liberia and also fitted outcome to infection generations in HCWs and in the community | Investigated the sensitivity of the model to parameters using LHS over a much wider range of the least-squares fit for each parameter | Assumed under-reporting by a factor of 2·5 |
| Fast et al. [47] | Case data from the Liberian Ministry of Health and Social welfare ad local county health offices. ETU admissions data from Github. Social mobilisation data from WHO and UNICEF reports. Parameters from UNICEF reports, WHO reports [1]. Population data from Liberian Institute of Statistics and Geo-information Services | Transmission model based on contact network. Accounts for change in attitudes that underlie behaviour change by simulating the progress of the EVD epidemic with and without population behaviour change, then comparing scenarios with observed data | Susceptible-exposed-infected-hospitalised-buried-unburied fatality-recovered (SEIHFCFBR) | Contact network model considered individuals as nodes and disease-spreading contacts as edges. Hospitalisation and fatality components were included | Model was fitted to weekly cases in Lofa County by considering the fitting metric of mean absolute error | NA | The model considered only cases that sought treatment or were safely buried, but modelled all cases |
| White et al. [48] | Case data from WHO [1] and daily counts from the public press releases from the Sierra Leonean Ministry of Health [17] | Developed compartmental model with six compartments to describe the outbreaks in Sierra Leone | Susceptible–exposed–infectious (not yet reported)–treated (reported)–dead (unreported)–recovered (reported)–dead (reported) (SEOTRDTRTD) | Considered infected and hospitalised individuals according to their reported status | Implemented an ensemble trajectory model and generated a matrix of plausible parameter values to fit the model for the first 56 days | NA | Used 2·5 correction factor estimated by the CDC to correct for underreporting |