Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.

Assessing the impact of mobility on epidemic spreading is of crucial importance for understanding the effect of policies like mass quarantines and selective re-openings. While many factors affect disease incidence at a local level, making it more or less homogeneous with respect to other areas, the...

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Main Authors: Mattia Mazzoli, Emanuele Pepe, David Mateo, Ciro Cattuto, Laetitia Gauvin, Paolo Bajardi, Michele Tizzoni, Alberto Hernando, Sandro Meloni, José J Ramasco
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2021-10-01
Series:PLoS Computational Biology
Online Access:https://doi.org/10.1371/journal.pcbi.1009326
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author Mattia Mazzoli
Emanuele Pepe
David Mateo
Ciro Cattuto
Laetitia Gauvin
Paolo Bajardi
Michele Tizzoni
Alberto Hernando
Sandro Meloni
José J Ramasco
author_facet Mattia Mazzoli
Emanuele Pepe
David Mateo
Ciro Cattuto
Laetitia Gauvin
Paolo Bajardi
Michele Tizzoni
Alberto Hernando
Sandro Meloni
José J Ramasco
author_sort Mattia Mazzoli
collection DOAJ
description Assessing the impact of mobility on epidemic spreading is of crucial importance for understanding the effect of policies like mass quarantines and selective re-openings. While many factors affect disease incidence at a local level, making it more or less homogeneous with respect to other areas, the importance of multi-seeding has often been overlooked. Multi-seeding occurs when several independent (non-clustered) infected individuals arrive at a susceptible population. This can lead to independent outbreaks that spark from distinct areas of the local contact (social) network. Such mechanism has the potential to boost incidence, making control efforts and contact tracing less effective. Here, through a modeling approach we show that the effect produced by the number of initial infections is non-linear on the incidence peak and peak time. When case importations are carried by mobility from an already infected area, this effect is further enhanced by the local demography and underlying mixing patterns: the impact of every seed is larger in smaller populations. Finally, both in the model simulations and the analysis, we show that a multi-seeding effect combined with mobility restrictions can explain the observed spatial heterogeneities in the first wave of COVID-19 incidence and mortality in five European countries. Our results allow us for identifying what we have called epidemic epicenter: an area that shapes incidence and mortality peaks in the entire country. The present work further clarifies the nonlinear effects that mobility can have on the evolution of an epidemic and highlight their relevance for epidemic control.
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spelling doaj.art-cd74a4a8b18043759485e785fa8832e72022-12-21T17:43:55ZengPublic Library of Science (PLoS)PLoS Computational Biology1553-734X1553-73582021-10-011710e100932610.1371/journal.pcbi.1009326Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.Mattia MazzoliEmanuele PepeDavid MateoCiro CattutoLaetitia GauvinPaolo BajardiMichele TizzoniAlberto HernandoSandro MeloniJosé J RamascoAssessing the impact of mobility on epidemic spreading is of crucial importance for understanding the effect of policies like mass quarantines and selective re-openings. While many factors affect disease incidence at a local level, making it more or less homogeneous with respect to other areas, the importance of multi-seeding has often been overlooked. Multi-seeding occurs when several independent (non-clustered) infected individuals arrive at a susceptible population. This can lead to independent outbreaks that spark from distinct areas of the local contact (social) network. Such mechanism has the potential to boost incidence, making control efforts and contact tracing less effective. Here, through a modeling approach we show that the effect produced by the number of initial infections is non-linear on the incidence peak and peak time. When case importations are carried by mobility from an already infected area, this effect is further enhanced by the local demography and underlying mixing patterns: the impact of every seed is larger in smaller populations. Finally, both in the model simulations and the analysis, we show that a multi-seeding effect combined with mobility restrictions can explain the observed spatial heterogeneities in the first wave of COVID-19 incidence and mortality in five European countries. Our results allow us for identifying what we have called epidemic epicenter: an area that shapes incidence and mortality peaks in the entire country. The present work further clarifies the nonlinear effects that mobility can have on the evolution of an epidemic and highlight their relevance for epidemic control.https://doi.org/10.1371/journal.pcbi.1009326
spellingShingle Mattia Mazzoli
Emanuele Pepe
David Mateo
Ciro Cattuto
Laetitia Gauvin
Paolo Bajardi
Michele Tizzoni
Alberto Hernando
Sandro Meloni
José J Ramasco
Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.
PLoS Computational Biology
title Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.
title_full Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.
title_fullStr Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.
title_full_unstemmed Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.
title_short Interplay between mobility, multi-seeding and lockdowns shapes COVID-19 local impact.
title_sort interplay between mobility multi seeding and lockdowns shapes covid 19 local impact
url https://doi.org/10.1371/journal.pcbi.1009326
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