Post-lockdown abatement of COVID-19 by fast periodic switching.

Michelangelo Bin,Lewi Stone,Robert Shorten,Pietro Ferraro,Connor Myant,Roderick Murray-Smith,Sebastian Stein,Emanuele Crisostomi,Peter Y K Cheung,Hugo Lhachemi,Thomas Parisini

doi:10.1371/journal.pcbi.1008604

Abstract

COVID-19 abatement strategies have risks and uncertainties which could lead to repeating waves of infection. We show-as proof of concept grounded on rigorous mathematical evidence-that periodic, high-frequency alternation of into, and out-of, lockdown effectively mitigates second-wave effects, while allowing continued, albeit reduced, economic activity. Periodicity confers (i) predictability, which is essential for economic sustainability, and (ii) robustness, since lockdown periods are not activated by uncertain measurements over short time scales. In turn-while not eliminating the virus-this fast switching policy is sustainable over time, and it mitigates the infection until a vaccine or treatment becomes available, while alleviating the social costs associated with long lockdowns. Typically, the policy might be in the form of 1-day of work followed by 6-days of lockdown every week (or perhaps 2 days working, 5 days off) and it can be modified at a slow-rate based on measurements filtered over longer time scales. Our results highlight the potential efficacy of high frequency switching interventions in post lockdown mitigation. All code is available on Github at https://github.com/V4p1d/FPSP_Covid19. A software tool has also been developed so that interested parties can explore the proof-of-concept system.

Highlights

The rapid spread of COVID-19 in early 2020 forced governments to move rapidly into a prolonged lockdown to curb the spread of the virus [1,2,3]
The work [1] is just one of many recent publications confirming that the prolonged lockdown policies put in place by different governments in eleven European countries led to a major decrease of the COVID-19 outbreak growth rate in the respective countries
Since pulsed intervention policies have been empirically shown to be effective in epidemiology, our starting point for our study is the question whether fast alternation of lockdown and normal society functioning would yield this compromise? We demonstrate that by modifying the epidemic’s dynamics towards an average behaviour, a Fast Periodic Switching Policy (FPSP) leads to the above-mentioned compromise

Summary

Introduction

The rapid spread of COVID-19 in early 2020 forced governments to move rapidly into a prolonged lockdown to curb the spread of the virus [1,2,3]. As a result of these interventions, new waves of COVID-19 emerge [10]; see for example the local lockdown in Leicester, England [11] In this respect, one of the great difficulties in designing intermittent lockdown policies based on real-time measurements comes from the many sources of uncertainty that surround the COVID-19 disease. One of the great difficulties in designing intermittent lockdown policies based on real-time measurements comes from the many sources of uncertainty that surround the COVID-19 disease These include: the delays and uncertainties of the available measurements; the time taken for an individual to become symptomatic, to become infectious, and to recover; the infection pathways (aerosols, surfaces); the proportion and infectivity of asymptomatic individuals, and many other factors. Uncertainty, delay and exponential growth, make any data-driven timing of lockdown, as well as the optimal timing of releasefrom lockdown, very difficult to determine (as we shall see later)

Methods

Results

Discussion

Conclusion