UNITED NATIONS - The U.N. Children's Fund UNICEF and the World Health Organization claimed a big boost to the global campaign for a polio-free world by 2005 on Friday with a vaccine maker's gift of 30 million doses of oral vaccine.

"This marks another milestone in the global effort to eradicate polio," said WHO Director-General Gro Harlem Brundtland at a ceremony marking the donation by Aventis Pasteur, a pharmaceutical firm headquartered in Strasbourg, France.

The vaccine will be distributed primarily in Africa, UNICEF officials said. Some 3 million doses were already en route to Liberia, they said.

As a result of the WHO campaign, launched in 1988 by 166 countries, the world was now "on the cusp" of eliminating polio, Brundtland said.

According to WHO statistics, the number of polio cases has fallen from 350,000 a year in 1988 to 480 last year.

During the same period, the number of countries in which the disease was widespread has declined to just 10 from 125 in 1988. The disease remains endemic in Afghanistan, Angola, Egypt, Ethiopia, India, Niger, Nigeria, Pakistan, Somalia and Sudan.

Polio, which mainly affects children under five, is caused by a virus that invades the nervous system and can cause total paralysis or even death.