Impact of pre-event testing and quarantine on reducing the risk of COVID-19 epidemic rebound: a modelling study

Ngai Sze Wong,Cheng Wang,Eng-Kiong Yeoh,Kate M Mitchell,Shui Shan Lee

doi:10.1186/s12879-021-06963-2

Abstract

BackgroundWith the evolving growth of the COVID-19 epidemic, travel restriction policies would need to be adjusted accordingly. Prohibition of mass event may be relaxed for social and economic benefits when virus transmission stops but could bear the risk of epidemic rebound. Against the background of the varied SARS-CoV-2 prevalence internationally, we modelled the potential impacts of pre-event interventions on epidemic risk of holding a mass event when COVID-19 is under control.MethodsWe developed a mathematical model of SARS-CoV-2 transmission in Guangdong Province, China, where local virus transmission ceased to occur. A large-scale international trade fair was assumed to be held, with influx of people from overseas and rest of China over a short period of time, who participated for 2-week. Scenarios of pre-event intervention (none, quarantine arrangement and polymerase chain reaction (PCR) testing for participants) were compared. The influence of contact pattern, SARS-CoV-2 prevalence outside the province and China, and testing coverage were examined in sensitivity analyses.ResultsIn basecase scenario (no event), the epidemic has been under control since March 2020. The event would lead to the detection of 1% more confirmed cases by 31 July when community contact rate increases to pre-epidemic level. In event scenario without additional interventions, there would be 599 (93%) more new infections comparing with basecase scenario. To avert new infections, quarantining all participants before the event would be the most effective strategy, followed by quarantining all overseas participants and testing all other participants, and testing all participants before the event and on day 7. However, testing strategy is likely to be affected by the SARS-CoV-2 prevalence outside the event province.ConclusionsPre-event interventions are effective for reducing the risk of epidemic rebound caused by an international large-scale event. Universal testing for participants is likely to be an effective and feasible intervention.

Highlights

With the evolving growth of the COVID-19 epidemic, travel restriction policies would need to be adjusted
Pre-event interventions are effective for reducing the risk of epidemic rebound caused by an interna‐ tional large-scale event
The model estimated that the number of cumulative local new infections reached the plateau of between 600 and 650 in midFebruary

Summary

Introduction

With the evolving growth of the COVID-19 epidemic, travel restriction policies would need to be adjusted . Against the background of the varied SARS-CoV-2 prevalence internationally, we modelled the potential impacts of pre-event interventions on epidemic risk of holding a mass event when COVID-19 is under control. International travel restriction have been adopted in most places to suppress the number of imported cases. Outbreaks have been reported in mass events in the earlier phase of the COVID-19 pandemic, as exemplified by clusters in a business conference in Singapore [3], and a Muslim missionary movement in Malaysia [4]. In coping with the pandemic, major international activities, such as large-scale trade, politics, religious, cultural, academic and sports events, have been cancelled, postponed or become virtual worldwide [5]

Methods

Results

Conclusion