Brazzaville/Dakar, 21 March 2012 -- Health Ministries, UN agencies and communities are uniting with tens of thousands of volunteer immunizers over four days to go door-to-door and hut to hut for a vaccination campaign against polio in 20 African countries starting on 23 March. Across West and Central Africa, over 111.1 million children below the age of five are expected to be vaccinated through this campaign. Nigeria, the only polio endemic country in Africa, aims to get two drops of the oral vaccine into the mouths of 57.7 million children. Nineteen other countries, which are at risk of re-infection, are stepping up efforts to reach nearly 53.3 million children.