Seventeen countries in West and Central Africa are gearing up for the largest public health initiative ever undertaken in the region: a massive cross-border polio immunization campaign that seeks to reach 70 million children all at once.

The so-called "synchronized" polio immunization campaign begins Saturday, 14 October and continues through Monday, 23 October.

The synchronized approach to polio immunization is the only way to reach every child in a region where labour migrations, conflict and natural disaster have caused frequent movement of populations across national boundaries. Such back-and-forth has put tens of thousands of children beyond the reach of traditional immunization efforts, which focus on one country at a time.

Thousands of health workers and trained volunteers will take part in the campaign, going door-to-door to make sure no child is missed.

The countries taking part are: Benin, Burkina Faso, Gambia, Ghana, Guinea Bissau, Guinea, Liberia, Mali, Mauritania, Niger, Nigeria, Senegal, Sierra Leone and Togo.

Nigeria is key to the effort because it is the largest remaining reservoir of wild poliovirus in Africa.

Three additional countries will join the effort during a second round of synchronized immunizations in mid-November. They are Cameroon, Chad and Côte d’Ivoire.

Two regional kick-off celebrations will take place. The first will be on 13 October in Niger, with President Mamadou Tandja of Niger and President Alpha Oumar Konare of Mali. On 14 October, President Olusegun Obasanjo of Nigeria will kick-off the campaign in his country. Both kick-offs are aimed at energizing parents, teachers, and community leaders in the final days before the campaign.

The partners in the Global Polio Eradication Effort are the World Health Organization (WHO), United States Centers for Disease Control and Prevention (CDC), Rotary International and the United Nations Children’s Fund (UNICEF), in addition to participating national governments and private foundations.