Dynamics of COVID-19 transmission including indirect transmission mechanisms: a mathematical analysis

Abstract

The outbreak of the novel coronavirus SARS-CoV-2 has raised major health policy questions and dilemmas. Whilst respiratory droplets are believed to be the dominant transmission mechanisms, indirect transmission may also occur through shared contact of contaminated common objects that is not directly curtailed by a lockdown. The conditions under which contaminated common objects may lead to significant spread of COVID-19 during lockdown and its easing is examined using the SEIR model with a fomite term added.Modelling the weekly death rate in the UK, a maximum likelihood analysis finds a statisticallysignificant fomite contribution, with 0.009± 0.001(95% CI) infection-inducing fomites introduced into the environment per day per infectious person. Post-lockdown, comparison with the prediction of a corresponding counterfactual model withno fomitetransmissionsuggests fomites, through enhancing theoverall transmissionrate, may have contributed to as much as 25 percent of the deaths following lockdown. It is suggested adding a fomite term to more complex simulations may assist in the understanding of the spread of the illness and in making policy decisions to control it.

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This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.

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DOI

https://doi.org/10.1017/S0950268820002563

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https://www.research.ed.ac.uk/portal/en/publications/dynamics-of-covid19-transmission-including-indirect-transmission-mechanisms-a-mathematical-analysis(b1eb2e3c-5ce6-4f5e-9351-2733f182483d).html