Pakistan's failure to stem the spread of polio has triggered global emergency health measures, with the World Health Organisation (WHO) recommending that all residents must show proof of vaccination before they can leave the country.
Monday’s emergency measures also apply to Syria and Cameroon, which along with Pakistan are seen as posing the greatest risk of exporting the crippling virus and undermining a UN plan to eradicate it by 2018.
Pakistan is in the spotlight, accounting for more than a fifth of the 417 cases reported globally in 2013.
The virus has recently spread to Afghanistan, Iraq, Israel and Syria, and has been found in sewage in the West Bank, Gaza Strip and greater Cairo, Bruce Aylward, WHO’s assistant director general, said.
It also appeared in China two years ago.
"In the majority of these reinfected areas, the viruses circulating actually trace back to Pakistan within the last 12-18 months," Aylward told reporters on a conference call.
Pakistan has called an emergency meeting of senior provincial and federal health officials on Wednesday to finalise how to implement the new requirements.
"The best option would be vaccinating the passengers at the airport departure where polio vaccination cards would be issued to the passengers. Human resource and vaccines would have to be worked out for the purpose," Saira Afzal Tarar, the state minister for health services, said in a televised broadcast.
"It would be most practical as people often have to fly in emergencies."
Aylward said Pakistan had done "tremendous" work to restore security in Peshawar after deadly attacks on health workers had impeded the fight against polio.
The race to meet a target to eradicate polio by 2018 was still feasible, he said.