Why do some countries manage to eradicate polio while others just can't? India had the most cases in the world and in a few years eradicated it against all odds. Yet in Nigeria, a much less populated country, polio is still a thread. Worsening things, the virus can come back as in Syria and Iraq, bringing the Middle East close to an epidemic. What is the key for a country to beat polio? And how can it be stopped from coming back? Thanks to the Innovation in Development Reporting Grant Programme by the European Journalism Centre, we have launch a project that aims at shedding light on the social, political, cultural and economical factors that affect the vaccination campaigns around the world. We travel to Nigeria to trace the work of NGOs and the struggle of the population to get the vaccines. In India, we look for the succesful story of polio eradication. And on the ground in Iraq we try to trace the way to content the latest outbreak of polio as the refugee crisis worsens and threat the neighboring countries.