Also, the smallpox vaccination was done with live bacteria, and the effect is (they said) the same as having had the disease and lasts for a lifetime. Should someone with a vaccination get the smallpox it would be a light case. So I have been told.
Quarantine is the only way to control small pox if it does surface. If the population won't quarentine the sick, then the healthy will have to quarantine themselves. If appearing in public is necessary a mask would also provide some protection. Flying during an outbreak would be really foolhardy, as the air on a plane is not conditioned, but simply recirculated. The worst colds and flu I have ever had have been immediately after a flight.