International health experts say the global campaign to eradicate polio has reached a critical stage, with Afghanistan, Pakistan and Nigeria the only countries where the crippling and potentially deadly virus is still prevalent.
Health officials in Pakistan say they are redoubling efforts to vaccinate every child against polio after 198 new cases were reported in the country last year, the largest number anywhere in the world.
But an ongoing insurgency and the influx of millions of Pakistani and Afghan refugees make that difficult.
And there's public opposition tied to reports the CIA used a fake vaccination program to hunt down al-Qaeda leader Osama bin Laden.
Carol Pandak manages the polio eradication program for the private group, Rotary International:
"We can stop polio, but we need the financial resources to finish the job and the accountability and advocacy on the political side in the remaining polio endemic countries so that the activities are carried out at a quality that can stop the transmission of the virus," said Pandak.
In northern Nigeria, public health officials have worked hard to counter false rumors that the polio vaccine contains birth-control drugs meant to suppress the country's Muslim population.
Even in the United States, there are anti-immunization groups that claim the vaccines can be unsafe for some people. Other critics, such as Barbara Loe Fisher, president of the National Vaccine Information Center, believe vaccine makers are promoting mass immunization solely to increase their profits.
"Certainly we have very powerful pharmaceutical corporations, multinational drug companies who are very interested in having as many doses of vaccines as possible, used by as many children all over the world as possible," Fisher said.
But Carol Pandak at Rotary International says too few people can recall how devastating polio can be. In one Nigerian village where leaders blocked immunizations, nine children fell sick with polio, leaving them partially paralyzed, their limbs deformed.
"I think we are almost a victim of our own success in this situation, because the parents don't see thousands and thousands of children paralyzed by polio," Pandak added. "So you don't see the reality of what the polio virus can do to children."
Anti-vaccination groups argue that some of the $9 billion spent so far on polio vaccinations could have been better used to improve sanitation conditions and child nutrition. But Pandak says that is another campaign. Right now, she says, a sustained commitment to mass vaccination could soon end polio forever.