An alternating lock-down strategy for sustainable mitigation of COVID-19

Lacking a drug or vaccine, our current strategy to contain the COVID-19 pandemic is by means of social distancing, specifically mobility restrictions and lock-downs. Such measures impose a hurtful toll on the economy, and are difficult to sustain for extended periods. The challenge is that selective isolation of the sick, an often viable and effective strategy, is insufficient against COVID-19, due to its relatively long incubation period, in which exposed individuals experience no symptoms, but still contribute to the spread. Here we propose an alternating lock-down strategy, in which at every instance, half of the population remains under lock-down while the other half continues to be active, maintaining a routine of weekly succession between activity and lock-down. All symptomatic individuals continue to remain in isolation. Under this regime, if an individual was exposed during their active week, by the time they complete their lock-down they will already begin to exhibit symptoms. Hence this strategy isolates the majority of exposed individuals during their asymptomatic phase. We find that this strategy not only overcomes the pandemic, but also allows for some level of flexibility, withstanding a fraction of defectors or essential workers that remain continuously active. We examine our strategy based on current epidemiological models with parameters relevant for COVID-19. We wish, however, following this communication, to further test and fine-tune our scheme based more refined data, and assess its actual effectiveness.