Measles/Whooping Cough come to mind as the benchmark for highly contagious.
Given we are already seeing the side effects of pandemic panic with overt misplaced racism (you look Asian therefor you're dangerous) and panic buying of supplies and price gouging, Further controls are going to put serious stress on primary care health services as more and more "walking well" fearing for their safety clog out GP's, Urgent Cares and ED's around the country which may lead to more health impacts and deaths than the actual virus.
So far we've got 106 cases confirmed world wide outside of China, Only 5 of which have had infection occur without any travel to China, Were starting to see those infected oversea's treated and released. We're still yet to have a death outside China and some effective treatment protocol's are starting to emerge. The situation inside China is murky at best so try not to transplant events and rumors from inside China with what is/may happen outside.