“The upcoming campaign in West and Central Africa will aim to cover all children, immunized or not, in order to boost their protection levels and deprive the virus of the fertile seedbed on which it depends for survival,” said the World Health Organization’s (WHO) Regional Director for Africa, Luis Sambo. “This exercise should bring us closer to reaching our goal of interrupting wild polio virus transmission in our region in 2012.”

The campaign, which will kick off on Friday, is intended to serve as a massive boost in efforts to eradicate the disease, and will involve national health ministries and UN agencies, as well as tens of thousands of volunteers who will go from door-to-door immunizing children.

In a news release today, the World Health Organization (WHO) and the UN Children’s Fund (UNICEF) described the campaign as entering a “decisive phase.”

“Either we succeed in eradicating polio today or this initiative will falter tomorrow and polio will explode,” said UNICEF’s Regional Director for West and Central Africa, David Gressly. “We will then see millions of children being paralyzed by this disease.”

Out of the 20 targeted countries, Nigeria is the only polio endemic country, and throughout its immunization period – which will start a week later for logistical reasons – it aims to provide 57.7 million children with two drops of oral vaccine each.

The other 19 countries are Chad, the Democratic Republic of the Congo (DRC), the Central African Republic (CAR), Niger, Cameroon, Benin, Burkina Faso, Cape Verde, Côte d’Ivoire, The Gambia, Ghana, Guinea, Guinea Bissau, Liberia, Mali, Mauritania, Senegal, Sierra Leone and Togo. Together, the 19 countries account for nearly 53.3 million children who will be targeted in the campaign.

Due to the presence of the disease in Nigeria, the risk of importation of the polio virus remains high in West Africa, with Cote d’Ivoire, Guinea, Mali and Niger having seen the resurgence of the virus last year.

To reduce the risk of transmission of the polio virus, the oral polio vaccine coverage must be sustained for a number of years. However, a WHO assessment conducted in February shows that there have been gaps in routine vaccination in most West African countries. The upcoming campaign aims to address these gaps and boost the population’s immunity levels.

Since the 1988 launch of the Global Polio Eradication Initiative – spearheaded by national governments, WHO, UNICEF, Rotary International, the US Centers for Disease Control and Prevention, and supported by the Bill & Melinda Gates Foundation – the incidence of polio has been reduced by more than 99 per cent. At the time, more than 350,000 children were paralyzed every year in more than 125 countries.

Last year, 650 cases were reported worldwide, and India – once regarded as the epicentre of polio – was declared to be free of the disease in January, reducing the number of polio-endemic countries to three: Afghanistan, Nigeria and Pakistan.