Nobody expected polio to be back.
It’s 2040, a decade since the disease was eradicated. The global health campaign that vanquished the virus has disbanded; immunization efforts have slackened. Then, one day, a sick child in a conflict-wracked country develops paralysis; the cause turns out to be polio. Scientists trace the origin of the virus to a laboratory on the other side of the world. A technician at the lab had handled a forgotten batch of polio-infected material — and then visited their family abroad.
As cases multiply, the World Health Organization (WHO) appeals for help to conduct emergency immunization campaigns, but stocks of vaccines are low and few members of staff have direct experience of polio outbreaks. Soon there are tens of thousands of cases: millions more people around the world who haven’t had the vaccine are at risk.