KINSHASA Health workers launched a program on Thursday to vaccinate 16 million children across four countries in a bid to stamp out the crippling polio virus in Central Africa, Reuters reported.

The horrific disfigurement caused by the preventable virus is a common sight across the continent where war has hampered efforts to end the scourge by mass vaccination programs.

The project in Angola, Congo Republic, the Democratic Republic of Congo and Gabon will target difficult areas such as refugee camps and volatile border areas where vaccination has been difficult in the past, allowing the virus a foothold despite a global elimination campaign.

The three-month program was launched in the Democratic Congo's capital, Kinshasa, on Thursday by Gro Harlem Brundtland, executive director of the World Health Organization, which aims to eliminate polio throughout the world by 2005.

"We urge the leaders of these countries and all parties to all conflicts to respect the coming days as days of tranquility to ensure the safe passage of health workers and volunteers," Brundtland said.

Angola and the Democratic Republic of Congo are both split by civil war, while the Republic of Congo is still recovering from a bloody 1997 civil war and subsequent militia violence.

The disease, whose full name is poliomyelitis, causes inflammation of nerve cells in the spinal cord and can cause permanent paralysis and disfigurement.