Before revision:    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.
After revision:  pre-symptomatic spreaders? 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.