The World Health Organisation said on Wednesday it plans to vaccinate 48 million people against yellow fever across West Africa over the next three years.
The campaign will start with the vaccination of 3.1 million people in Senegal this week, and aims to increase vaccination coverage to at least 80 percent of the targeted population across the region, the WHO said in a statement.
Senegal has not known any cases of yellow fever since 2002, but the WHO warned that as vaccination coverage rates are only at around 46 percent in some districts, it could be vulnerable to an epidemic if the fever struck again.
The campaign aims to "increase the public health security of the entire region by reducing the chance of a yellow fever epidemic to the greatest extent possible," the WHO said.
After Senegal, the vaccinations will continue in Mali, Burkina Faso, Benin, Cameroon, Guinea, Ghana, Ivory Coast, Liberia, Nigeria and Sierra Leone, and will target all those over the age of nine months who live in high-risk areas, the UN health body said.
In the long-term, the WHO hopes to reach all those in Africa who need vaccination -- approximately 240 million people.
The campaign is funded by a variety of partners including a 63 million dollar (43 million euro) donation from the Global Alliance for Vaccines and Immunisation, which will pay for 58 million doses of vaccine and supplies.
Yellow fever is an acute, haemorrhagic, viral disease transmitted to humans by infected mosquitoes.