The governor of Nigeria’s northern Kano state, focus of polio outbreaks in parts of west Africa, has pledged to start an immunization program in early July, the World Health Organization (WHO) said Wednesday.

Last week, the WHO said west and central Africa were on the verge of their largest polio epidemic in years as the virus was spreading out from Nigeria’s largely Muslim north.

“The WHO has been informed by the governor of Kano of the intention to resume polio immunization campaigns there in early July,” a statement from the health organization said.

Kano and other northern states halted the campaign a year ago after assertions by Muslim leaders that the U.N.-supplied vaccine was unsafe. Since then, polio has spread into neighboring countries and as far afield as Sudan and Botswana.

The outbreak has been a major setback to a WHO campaign to eradicate the disease - endemic in only six countries including India in 2003 - by the end of 2005.

David Heymann, a specialist on the issue for the U.N. agency, told a news conference that it was vital to act now because the coming rainy season would create ideal conditions for the virus to spread and could worsen the situation.

He also said that international travelers to Nigeria’s north remained at high risk and should ensure they were protected against the disease.

There have already been 62 new infections in Nigeria over the past two weeks, with a total of 259 confirmed polio cases in the country.

Heymann said the WHO and the U.N. children’s agency UNICEF had vaccines and personnel in place and were ready to launch an emergency drive in Kano to ensure that every child was immunized against the disease.

The WHO’s polio coordinator, Bruce Aylward, said last week that unless action was taken quickly to close down the epicenter of the disease in northern Nigeria, thousands of children across west and central Africa could be crippled by it.

Initially, some Muslim elders had suspected the vaccine of reducing fertility as part of a U.S.-led drive against Islam, but Heymann said the governor had told the WHO by telephone that he was now satisfied the vaccine was safe.

WHO Director-General Lee Jong-Wok welcomed the governor’s decision. The suspension of the campaign in the north of Nigeria last year, he said in a statement, “has resulted in the re-emergence of polio in countries which had been polio-free.”