The Spread of COVID-19 in London: Network Effects and Optimal Lockdowns

42 Pages Posted: 22 Oct 2020 Last revised: 2 Nov 2020

See all articles by Christian Julliard

Christian Julliard

London School of Economics & Political Science (LSE) - Department of Finance; Centre for Economic Policy Research (CEPR)

Ran Shi

London School of Economics & Political Science (LSE) - Department of Finance

Kathy Yuan

London School of Economics & Political Science (LSE) - Department of Finance

Date Written: October 19, 2020

Abstract

We generalise a stochastic version of the workhorse SIR (Susceptible-Infectious- Removed) epidemiological model to account for spatial dynamics generated by network interactions. Using the London metropolitan area as a salient case study, we show that commuter network externalities account for about 42% of the propagation of COVID-19. We find that the UK lockdown measure reduced total propagation by 57%, with more than one third of the effect coming from the reduction in network externalities. Counterfactual analyses suggest that: i) the lockdown was somehow late, but further delay would have had more extreme consequences; ii) a targeted lockdown of a small number of highly connected geographic regions would have been equally effective, arguably with significantly lower economic costs; iii) targeted lockdowns based on threshold number of cases are not effective, since they fail to account for network externalities.

Note: Funding: None to declare.

Declaration of Interests: None to declare.

Keywords: COVID-19, networks, key players, spatial modelling, SIR model

JEL Classification: I12, I18, C31, C51, D85

Suggested Citation

Julliard, Christian and Shi, Ran and Yuan, Kathy Zhichao, The Spread of COVID-19 in London: Network Effects and Optimal Lockdowns (October 19, 2020). Available at SSRN: https://ssrn.com/abstract=3715047 or http://dx.doi.org/10.2139/ssrn.3715047

Christian Julliard (Contact Author)

London School of Economics & Political Science (LSE) - Department of Finance ( email )

United Kingdom

Centre for Economic Policy Research (CEPR) ( email )

London
United Kingdom

Ran Shi

London School of Economics & Political Science (LSE) - Department of Finance ( email )

United Kingdom

Kathy Zhichao Yuan

London School of Economics & Political Science (LSE) - Department of Finance ( email )

Old Building
Houghton Street
London, London WC2A 2AE
United Kingdom
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HOME PAGE: http://fmg.lse.ac.uk/~kathy

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