A national polio immunisation campaign is due to resume in Nigeria, but one northern state is refusing to join in.
Kano officials remain unhappy with the vaccine
Kano opted out of a drive last year, when some Islamic leaders said it was part of a western plot to render Muslim women infertile.
Last week the government announced that the oral vaccine, promoted by the United Nations, was safe to use.
The programme targets about 60 million children and centres on Nigeria - where half of all new polio cases originate.
The northern state of Zamfara, which boycotted the campaign last year, is joining in this time.
President Olusegun Obasanjo chose the capital of Zamfara, Gusau, to launch the latest round of vaccinations.
"Since the controversy over the polio vaccine started, thousands of children in this state have been denied the opportunity to be immunised against the devastating disease and that has not augured well," the president said during a televised ceremony.
Health experts have warned that the delay in vaccination in Kano has already resulted in new polio cases.
The World Health Organization has denied the claims by Muslim clerics that the vaccine was contaminated with an anti-fertility agent.
And its goal of eradicating polio from the world by next year is now looking increasingly distant.
Polio has spread out from northern Nigeria to infect people in at least seven west and central African states.
Kano announced earlier this month that it would seek polio vaccines from Asian countries.
But state spokesman Sule Ya'u Sule told AP news agency on Sunday that Kano would not be joining in.
"We will only join when we receive uncontaminated vaccines or when our own vaccines arrive," he said.