Abstract
BackgroundWith at least 94 countries undergoing or exiting lockdowns for contact suppression to control the COVID-19 outbreak, sustainable and public health-driven exit strategies are required. Here we explore the impact of lockdown and exit strategies in Singapore for immediate planning. MethodsWe use an agent-based model to examine the impacts of epidemic control over 480 days. A limited control baseline of case isolation and household member quarantining is used. We measure the impact of lockdown duration and start date on final infection attack sizes. We then apply a 3-month gradual exit strategy, immediately re-opening schools and easing workplace distancing measures, and compare this to long-term social distancing measures. FindingsAt baseline, we estimated 815 400 total infections (21.6% of the population). Early lockdown at 5 weeks with no exit strategy averted 18 500 (2.27% of baseline averted), 21 300 (2.61%) and 22 400 (2.75%) infections for 6, 8 and 9-week lockdown durations. Using the exit strategy averted a corresponding 114 700, 121 700 and 126 000 total cases, representing 12.07–13.06% of the total epidemic size under baseline. This diminishes to 9 900–11 300 for a late 8-week start time. Long-term social distancing at 6 and 8-week durations are viable but less effective. InterpretationGradual release exit strategies are critical to maintain epidemic suppression under a new normal. We present final infection attack sizes assuming the ongoing importation of cases, which require preparation for a potential second epidemic wave due to ongoing epidemics elsewhere. FundingSingapore Ministry of Health, Singapore Population Health Improvement Centre.
Highlights
In response to the rising number of local coronavirus disease 2019 (COVID-19) cases, many countries have implemented lockdowns to restrict movement and community interactions and thereby suppress infection
For lockdowns implemented at later weeks, substantial proportions of cases are averted, as observed for other epidemics [20], with a final infection attack size of 591 500 (577 800–600 100) at week 8 as an example, this will not be viable for most countries where their healthcare capacity cannot cope with large, early epidemic peaks
When gradual release exit strategy (GRES) is compared with no exit strategy for a 5 and 6week implementation start time, it results in a reduction of 8.01– 13.06% in final infection attack size, and 0.78–1.91% reduction for a 7 and 8 week start time as a large proportion of cases have already occurred in the initial epidemic ramp up
Summary
In response to the rising number of local coronavirus disease 2019 (COVID-19) cases, many countries have implemented lockdowns to restrict movement and community interactions and thereby suppress infection. With at least 94 countries undergoing or exiting lockdowns for contact suppression to control the COVID-19 outbreak, sustainable and public health-driven exit strategies are required. We measure the impact of lockdown duration and start date on final infection attack sizes. We apply a 3-month gradual exit strategy, immediately re-opening schools and easing workplace distancing measures, and compare this to long-term social distancing measures. Using the exit strategy averted a corresponding 114 700, 121 700 and 126 000 total cases, representing 12.07–13.06% of the total epidemic size under baseline. This diminishes to 9 900–11 300 for a late 8-week start time.
Sign-in/Register to view highlights & summary 
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call