Model Structure

The LMIC reports are generated using an age-structured SEIR model. The developed model is an extension of the model used in our previous report (see Report 12) and the source code for the model can be found at https://github.com/mrc-ide/squire. In this model, the infectious class is divided into different stages reflecting progression through different disease severity pathways. These compartments are:


Given initial inputs of hospital/ICU bed capacity and the average time cases spend in hospital, the model dynamically tracks available hospital and ICU beds over time. Individuals newly requiring hospitalisation (either a hospital or ICU bed) are then assigned to either receive care (if the relevant bed is available) or not (if maximum capacity would be exceeded otherwise). Whether or not an individual receives the required care modifies their probability of dying.

Interventions

Version 6

No new model fitting or intervention changes implemented in Version 6. The main changes relate to the parameter update (see Model Parameters section below).

Changes have been made in order to provide scenarios for countries that are yet to document any COVID-19 deaths. These scenarios are noted in the data for that country within the new data column - death_calibrated - that describes whether the scenario is the result of model fits calibrated to death data. In countries with no deaths to date, we provide scenario projections of what would happen if 5 imported cases occurred today with no future intervention changes. We assume three different R0s. For our upper estimate, we assume that R0 is equal to the mean R0 of c