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A Modified SEIR Model to Predict the COVID-19 Outbreak in Spain and Italy: Simulating Control Scenarios and Multi-Scale Epidemics
21 Pages Posted: 29 Apr 2020
More...Abstract
After the spread of SARS-CoV-2 epidemic out of China, evolution in the pandemic worldwide shows dramatic differences among countries. In Europe, the situation of Italy first and later Spain has generated great concern, and despite other countries show better prospects, large uncertainties yet remain on the future evolution and the efficacy of containment, mitigation or attack strategies. Here we applied a modified SEIR compartmental model accounting for the spread of infection during the latent period, in which we also incorporate effects of varying proportions of containment. We fit data to quarantined populations in order to account for the uncertainties in case reporting and study the scenario projections for the 17 individual regions (CCAA). Results indicate that with data for March 23, the epidemics follows an evolution similar to the isolation of 1; 5 percent of the population and if there were no effects of intervention actions it might reach a maximum over 1:4M infected around April 27. The effect on the epidemics of the ongoing partial confinement measures is yet unknown (an update of results with data until March 31st is included), but increasing the isolation around ten times more could drastically reduce the peak to over 100k cases by early April, while each day of delay in taking this hard containment scenario represents an 90 percent increase of the infected population at the peak. Dynamics at the sub aggregated levels of CCAA show epidemics at the different levels of progression with the most worrying situation in Madrid an Catalonia. Increasing alpha values up to 10 times, in addition to a drastic reduction in clinical cases, would also more than halve the number of deaths. Updates for March 31st simulations indicate a substantial reduction in burden is underway. A similar approach conducted for Italy pre- and post-interventions also begins to suggest substantial reduction in both infected and deaths has been achieved, showing the efficacy of drastic social distancing interventions.
Funding Statement: We acknowledge support from the Spanish Ministry of Science and Innovation through the “Centro de Excelencia Severo Ochoa 2019-2023” Program (CEX2018000806S), and support from the Generalitat de Catalunya through the CERCA Program. Partial funding support for X. Rodó was received from the ISCIII COVID-19 project COV20/00144 and from a project by the Fundació Daniel Bravo Andreu.
Declaration of Interests: The authors declare no competing interest.
Ethics Approval: All data used are completely anonymous and from public data repositories. No other ethical consideration was estimated by the Ethics Committee.
Keywords: SARS-CoV-2; modified SEIR compartmental model; segmented quarantine; Spain; Italy; Multi-scale; pre- and post-confinement scenarios; latent spread simulations
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