By Tume Ahemba
LAGOS, Nov 25 (Reuters) - Nigeria will launch a new campaign to vaccinate millions of children against polio on Wednesday in an attempt to curb the spread of the disease that has crippled hundreds this year, the World Health Organisation said.
Africa's most populous country, which accounts for more than 50 percent of new polio cases in the world, has struggled to tame the contagious disease since some states in the mainly Muslim north imposed a year-long vaccine ban in mid-2003.
New polio infections in Nigeria have climbed 225 percent to 751 this year from the same period last year because many children in the north missed several rounds of immunisation towards the end of 2007, health officials said.
The immunisation drive runs until Nov. 30 in 17 northern states and from Dec. 10-12 for the rest of the country.
"The challenge is now for all stakeholders to ensure that all eligible children in Nigeria are indeed taken to the vaccination posts ... to receive these vaccines and supplements," WHO said in a notice.
Children need multiple doses of the oral vaccine to develop full immunity to the incurable infection.
The Nigerian government has set up a presidential task force to bolster the national immunisation effort.
Only four countries -- Nigeria, India, Pakistan and Afghanistan -- remain endemic for the disease that spreads through poor hygiene.
Nigeria has come under pressure to boost immunisation since May when neighbouring Benin reported its first infection in four years. The virus had first spread to Nigeria's northern neighbours Chad and Niger, WHO said.
Polio, which can cause permanent paralysis in children, can be prevented with vaccines that have eliminated the virus as a public health threat in most parts of the world.
The global polio eradication initiative, run by WHO, UNICEF, Rotary International and the United States Centers for Disease Control and Prevention, has spent more than $6 billion to fight the scourge in the remaining affected countries.
One major setback was the suspension of immunisation in northern Nigeria in 2003, when Muslim leaders told parents that the vaccines could endanger their children.
(Reporting by Tume Ahemba; Editing by Randy Fabi and Giles Elgood)