On May 5, the U.N.’s World Health Organization declared the “extraordinary” spread of polio this year so far as a “public health emergency of international concern” and recommended temporary measures for 10 states at risk during the high-transmission season of May through June. Since 60 percent of polio cases this year spread from international travel by adults, it wants polio-exporting nations—Pakistan, Cameroon, Syria—to arm citizens traveling abroad with proof that they have been immunized. The agency has advised these measures be reassessed in three months and stay in place for up to a year. Leaping into action the following day, the Punjab government said all children coming into the province would be immunized, by force if necessary. Similar facilities are being planned for around the country. Pakistan’s former president Asif Ali Zardari has urged WHO to reconsider its edict. “The imposition of a travel ban will only increase Pakistan’s isolation and not advance the global fight against polio,” he said.