"There's no way to sugarcoat the last 12 months," Bruce Aylward, a WHO official, told Mr. Gates in the meeting in the underground pandemic center last June. He described how the virus was rippling through countries believed to have stopped the disease.
Mr. Gates asked: "So, what do we do next?"
That question goes to the heart of one of the most controversial debates in global health: Is humanity better served by waging wars on individual diseases, like polio? Or is it better to pursue a broader set of health goals simultaneously—improving hygiene, expanding immunizations, providing clean drinking water—that don't eliminate any one disease, but might improve the overall health of people in developing countries?
The new plan integrates both approaches. It's an acknowledgment, bred by last summer's outbreak, that disease-specific wars can succeed only if they also strengthen the overall health system in poor countries.
If successful, the recalibrated campaign could shape global health strategy for decades and boost fights against other diseases. A failure could rank the effort as one of the most expensive miscalculations in mankind's long war with disease. Already, polio has evaded a two-decade-long, $8.2 billion effort to kill it off.
Big donors have long preferred fighting individual diseases, known as a "vertical" strategy. The goal is to repeat 1979's victory over smallpox, the only disease ever to be eradicated. By contrast, the broader, "horizontal" strategy has less well-defined goals and might not move the needle of global health statistics for years.
The polio fight is a lesson for Mr. Gates's foundation, which is funding other vaccines that could face similar setbacks.