The World Health Organization has announced the launch of a mass polio vaccination campaign across Africa.
The WHO says 15 countries are taking part in a drive to immunize 72 million children against the crippling disease. It says that beginning this week, vaccinators will be going door-to-door in the "highest risk" polio areas to give children under five years old two drops of oral polio vaccine.
The WHO and African governments have launched similar drives over the past two years following a series of outbreaks in west Africa and the Horn of Africa. It says the biggest current outbreaks are in Angola and the Democratic Republic of Congo, which have 25 cases and 28 cases, respectively. Both of those countries are taking part in this week's campaign.
Other countries taking part include Ivory Coast, Benin, Burkina Faso, Gambia, Guinea, Mali, Mauritania, Senegal, Sierra Leone, Liberia, Chad, Sudan. Nigeria began immunizing children last week.
Polio was once widespread and paralyzed thousands of children each year. Today, after years of immunization campaigns, the disease remains endemic in just four countries - Nigeria, Afghanistan, Pakistan and India.