A predominantly Muslim state in northern Nigeria said on Thursday it would not take part in a polio immunisation campaign despite assurances from the Nigerian government that the vaccines were safe.

Kano state stopped immunising children against the crippling virus six months ago after Islamic authorities voiced concerns that existing vaccines were tainted with infertility agents and could spread HIV.

A team of health officers and Muslim leaders established last month to investigate contamination submitted its final report to Nigerian President Olusegun Obasanjo on Wednesday, saying the vaccines were safe.

But the Kano state government said on Thursday it would not take part in an immunisation scheduled for March 22-26 and was waiting for a delivery of fresh vaccines from Asia.

“Kano state government has reaffirmed its stand on the suspension of polio eradication programme,” the statement said.

“Kano state government would source polio vaccines from other internationally recognised pharmaceutical companies to address the prevalence of the disease.”

The United Nations agency said since the suspension began in September, 400 Nigerian children had been infected with polio and the virus has since spread to eight other countries in West and Central Africa where it had previously been eradicated.

The spread of the virus has jeopardised a U.N. target of eliminating the disease globally by 2005.

UNICEF and other global health bodies are sponsoring an immunisation campaign covering 63 million children in 10 West African countries that began in February.

Nigeria, one of five countries where the disease is endemic, accounted for about half of all 758 polio cases worldwide last year, according to the World Health Organisation.