The Global Polio Eradication Initiative has resulted in a drop in recorded polio cases to just 3,500 in 2000, compared with 350,000 cases recorded in 1988.
The initiative sent health workers door-to-door -- or sometimes from mud hut to mud hut -- immunizing 550 million children under age 5 in 82 countries last year.
"The key now is urgently accessing and vaccinating the children we haven't been able to reach because of war, isolation and lack of infrastructure," said UNICEF executive director Carol Bellamy.
"It's essential that warring parties and international mediators give priority to cease-fires that allow us to get polio vaccine to these children."
Polio is a crippling and sometimes fatal disease that attacks the central nervous system. The initiative's goal is to eradicate polio worldwide by 2005.
The virus is now found in only 20 countries, mainly in South Asia and sub-Saharan Africa, compared to 125 countries in 1988.
The initiative will start intensive vaccination programs in Angola and Congo this year, the statement said. U.N. officials have begun negotiating with the warring parties in those countries to have "Days of Tranquility," which will allow health workers into war zones and allow the children to gather safely to receive vaccine.
Polio vaccine is cheap - 9 cents a dose - said Christopher Maher of the World Health Organization. But delivering the doses needed to vaccinate 600 million children in the next four years will cost $1 billion. Children must take repeated doses over several years for the vaccine to be effective.
The oral vaccine, a relatively safe form of the live virus, is preferred in part because it is contagious and can give what experts call "herd immunity." But if too many children are unvaccinated, the virus can circulate in the population long enough to mutate back into a virulent strain.
The eradication initiative is a joint project of the WHO, the U.N. Children's Fund, Rotary International and the U.S. Centers for Disease Control and Prevention.
Rotary volunteers have played a key role in raising money and helping carry out the vaccinations, U.N. officials said. Rotary members in 163 countries have donated $407 million and have pledged $ 500 million more, said Frank Devlyn, president of Rotary International.
Containing the virus quickly is key to the program's success. The small West African island nation of Cape Verde, which was free of polio for years, had an outbreak in August 2000 when an Angolan child with the virus moved there. Seventeen children were killed by the disease and 44 children were paralyzed before the outbreak was contained.
"Victory over the polio virus is within sight," said Dr. GrHarlem Bruntland, director-general of WHO. "We must now close in on the remaining strongholds of the disease."
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