Tens of thousands of health workers will go house to house over the next three days in an effort to immunize sixty three million children under the age of five in sub-Saharan Africa. The campaign is the start of monthly national immunization days during the low season for Polio.
It's hoped that vaccinating children now - when the virus is at its weakest - will be the best way of stopping transmission. When the Polio campaign started in 1988, a thousand children were paralysed every day by the virus, last year less than eight hundred children were affected in total.
But claims by local religious leaders that the vaccine is unsafe have seriously hampered efforts to stop Polio spreading - not only in Nigeria, but also in India and Pakistan - where similar immunization schemes are due to begin shortly. However the Global Polio Eradication Initiative, as well as state officials and religious leaders have commissioned independent tests that show the vaccine to be safe.