In a most realistic storyline, the media causes a frenzy, and the World Health Organisation (WHO) is forced to declare a global emergency and Interpol confirms the outbreak is a bioterrorism attack.
Airports and shipping ports are then closed down, but things get worse as many doctors and nurses die, while the remaining call a strike.
Vaccines arrive in Fiji, but the simulation predicts that the smallpox has already spread to other, more populous, countries in Asia.
The researchers added: “In a worst-case scenario, at the peak of the epidemic, worldwide, only 50 percent of smallpox cases are isolated and only 50 percent of contacts are tracked and vaccinated, causing a catastrophic blow-out in the epidemic.