How to Finish the Last, Hard Path to Polio Eradication

The end of polio is in sight. Last year, there were fewer cases of the disease -- 223 -- in fewer endemic countries -- three -- than ever. Still, the eradication campaign can seem like Achilles’ effort to outrun the tortoise in Zeno’s paradox: There’s always a little more ground to cover.

The goal can be achieved only if health workers can find and inoculate the last unvaccinated children on earth. That’s going to take an estimated $5.5 billion (in addition to the $9 billion spent so far), a huge commitment from endemic-country governments and a push by Muslim leaders to counter anti-vaccination extremists.