Coronavirus (COVID-19): modelling the epidemic (issue no. 4)

Latest findings in modelling the COVID-19 epidemic in Scotland, both in terms of the spread of the disease through the population (epidemiological modelling) and of the demands it will place on the system, for example in terms of health care requirement.


Annex. Modelling amendments

To improve the model fit the PHS data[1] has been substituted with NRS data.[2] This has resulted improved fitting of modelled estimates of deaths which results in altering the estimates of incidence and subsequently R to account for all covid related deaths based on this being on the death certificate. However the logistical model, which is based on new infections, continues to be use a model fit to the PHS data as PHS is our source of positive cases. So both sources are now used.

The model has also been updated to reflect the move in Scotland to phase 1 of "Coronavirus (COVID-19): framework for decision making - Scotland's route map through and out of the crisis". Through the inclusion of additional covariates representing phase 1 - 4.

A review was undertaken of European countries to identify equivalent phase 1-4 activities (to date none of these countries, except Sweden who did not lockdown, have implemented phase 4 equivalent activities), to establish changes in data behaviour as a result of phases. Due to differential timelines between countries, it is assumed that the first implementation of a phase equivalent activity is classified as that country being in that phase.

Three additional countries of similar population size to Scotland (Slovakia, Ireland and Finland) were included to the original 13 countries to provide sampling of epidemic behaviours in similar sized populations. The case and death data for these countries are extracted from the ECDC[3] Table 2 outlines the dates applied for each country initiated a phase equivalent activity.

Table 2. Dates were countries apply their first phase equivalent activity.
Country Phase 1 equivalent Phase 2 equivalent Phase 3 equivalent
Denmark 15/04/2020 20/04/2020 20/04/2020
Italy 14/04/2020 14/04/2020 18/05/2020
Germany 15/04/2020 15/04/2020 04/05/2020
Spain 13/04/2020 11/05/2020 11/05/2020
France 11/05/2020 11/05/2020 11/05/2020
Norway 27/04/2020 20/04/2020 27/04/2020
Belgium 04/05/2020 04/05/2020 11/05/2020
Austria 14/04/2020 14/04/2020 01/05/2020
Sweden
Switzerland 27/04/2020 11/05/2020 27/04/2020
Greece 04/05/2020 04/05/2020 11/05/2020
Portugal 04/05/2020 04/05/2020 04/05/2020
Netherlands 01/06/2020 01/06/2020 11/05/2020
Scotland 29/05/2020
England 13/05/2020 01/06/2020
Wales 01/06/2020
NI 18/05/2020
Ireland 05/05/2020 05/05/2020 18/05/2020
Slovakia 22/04/2020 22/04/2020 06/05/2020
Finland 13/05/2020 14/05/2020 01/06/2020

Contact

Email: modellingcoronavirus@gov.scot

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