There is an interesting sidebar at this time on immune responses vs sleep, logically presented on youtube, on medcram.com, update 17.
The presentation makes a good case to sleep behaviour that would cause variations in the outcome from an infection. The variables may be applicable to some of the cases that have been seen so far, making a case that a good nights sleep is desirable. Worth a coffee break to watch and draw your own conclusions. The conclusion that could be drawn from the referenced studies is that an outbreak would have a more adverse outcome in a group that work activity results in poor quality of sleep and a level of sleep deprivation. A hard working workforce would be at risk, say countries that have a concentration on time at work, poor rest conditions and limited time in rest. That may sound like every airline pilot in the world, but the studies make cases that suggest the airline FDL's are beneficial.