@article{67e598f8fca747b4aff76d6836e9663c,
title = "The importance of saturating density dependence for population-level predictions of SARS-CoV-2 resurgence compared with density-independent or linearly density-dependent models, England, 23 March to 31 July 2020",
abstract = "Background: Population-level mathematical models of outbreaks typically assume that disease transmission is not impacted by population density ({\textquoteleft}frequency-dependent{\textquoteright}) or that it increases linearly with density ({\textquoteleft}density-dependent{\textquoteright}). Aim: We sought evidence for the role of population density in SARS-CoV-2 transmission. Methods: Using COVID-19-associated mortality data from England, we fitted multiple functional forms linking density with transmission. We projected forwards beyond lockdown to ascertain the consequences of different functional forms on infection resurgence. Results: COVID-19-associated mortality data from England show evidence of increasing with population density until a saturating level, after adjusting for local age distribution, deprivation, proportion of ethnic minority population and proportion of key workers among the working population. Projections from a mathematical model that accounts for this observation deviate markedly from the current status quo for SARS-CoV-2 models which either assume linearity between density and transmission (30% of models) or no relationship at all (70%). Respectively, these classical model structures over- and underestimate the delay in infection resurgence following the release of lockdown. Conclusion: Identifying saturation points for given populations and including transmission terms that account for this feature will improve model accuracy and utility for the current and future pandemics.",
author = "Nightingale, {Emily S.} and Oliver Brady and {CMMID COVID-19 Working Group} and Laith Yakob and Amy Gimma and Mark Jit and Jarvis, {Christopher I.} and Waterlow, {Naomi R.} and Procter, {Simon R.} and Megan Auzenbergs and Tully, {Damien C.} and David Simons and Akira Endo and Joel Hellewell and Rachel Lowe and Foss, {Anna M.} and {van Zandvoort}, Kevin and Pearson, {Carl A.B.} and Alicia Showering and Petra Klepac and Graham Medley and Quilty, {Billy J.} and Charlie Diamond and Edmunds, {W. John} and Alicia Rosello and Barnard, {Rosanna C.} and Kaja Abbas and Katharine Sherratt and Jack Williams and Meakin, {Sophie R.} and Matthew Quaife and Russell, {Timothy W.} and Villabona-Arenas, {C. Julian} and Kiesha Prem and Sun, {Fiona Yueqian} and Davies, {Nicholas G.} and Eggo, {Rosalind M.} and Knight, {Gwenan M.} and Kucharski, {Adam J.} and Sandmann, {Frank G.} and Sebastian Funk and Gore-Langton, {Georgia R.} and Stefan Flasche and Thibaut Jombart and Gibbs, {Hamish P.} and Yang Liu and Oliver Brady and Bosse, {Nikos I.} and Chan, {Yung Wai Desmond} and Sam Abbott and Samuel Clifford and Atkins, {Katherine E.} and Munday, {James D.}",
note = "Funding Information: Funding: OJB was funded by a Sir Henry Wellcome Fellowship funded by the Wellcome Trust (206471/Z/17/Z). ESN is funded by the Bill and Melinda Gates Foundation (OPP1183986). Publisher Copyright: {\textcopyright} 2021 European Centre for Disease Prevention and Control (ECDC). All rights reserved.",
year = "2021",
month = dec,
day = "9",
doi = "10.2807/1560-7917.ES.2021.26.49.2001809",
language = "English",
volume = "26",
journal = "Eurosurveillance",
issn = "1025-496X",
publisher = "EUR CENTRE DIS PREVENTION & CONTROL",
number = "49",
}