Using a household-structured branching process to analyse contact tracing in the SARS-CoV-2 pandemic

Fyles, Martyn, Fearon, Elizabeth, Overton, Christopher, Wingfield, Tom ORCID: https://orcid.org/0000-0001-8433-6887, Medley, Graham F, Hall, Ian, Pellis, Lorenzo and House, Thomas (2021) 'Using a household-structured branching process to analyse contact tracing in the SARS-CoV-2 pandemic'. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, Vol 376, Issue 1829, p. 20200267.

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Abstract

We explore strategies of contact tracing, case isolation and quarantine of exposed contacts to control the SARS-CoV-2 epidemic using a branching process model with household structure. This structure reflects higher transmission risks among household members than among non-household members. We explore strategic implementation choices that make use of household structure, and investigate strategies including two-step tracing, backwards tracing, smartphone tracing and tracing upon symptom report rather than test results. The primary model outcome is the effect of contact tracing, in combination with different levels of physical distancing, on the growth rate of the epidemic. Furthermore, we investigate epidemic extinction times to indicate the time period over which interventions must be sustained. We consider effects of non-uptake of isolation/quarantine, non-adherence, and declining recall of contacts over time. Our results find that, compared to self-isolation of cases without contact tracing, a contact tracing strategy designed to take advantage of household structure allows for some relaxation of physical distancing measures but cannot completely control the epidemic absent of other measures. Even assuming no imported cases and sustainment of moderate physical distancing, testing and tracing efforts, the time to bring the epidemic to extinction could be in the order of months to years.

Item Type:	Article
Additional Information:	This article is part of the theme issue 'Modelling that shaped the early COVID-19 pandemic response in the UK'
Subjects:	WA Public Health > WA 105 Epidemiology WA Public Health > Preventive Medicine > WA 108 Preventive health services. Preventive medicine. Travel Medicine. WA Public Health > Preventive Medicine > WA 110 Prevention and control of communicable diseases. Transmission of infectious diseases WC Communicable Diseases > Virus Diseases > Viral Respiratory Tract Infections. Respirovirus Infections > WC 505 Viral respiratory tract infections
Faculty: Department:	Clinical Sciences & International Health > Clinical Sciences Department
Digital Object Identifer (DOI):	https://doi.org/10.1098/rstb.2020.0267
Depositing User:	Julie Franco
Date Deposited:	05 Jul 2021 09:09
Last Modified:	05 Jul 2021 09:09
URI:	https://archive.lstmed.ac.uk/id/eprint/18152

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