Today the World Health Organization (WHO) kicks off a five-day campaign to give a polio vaccination to every child under five in four central African countries.
Whereas the rest of the world is largely free of the disease, the difficulties of vaccinating children in areas of civil unrest or with a poor health-care infrastructure have kept the crippling disease rife in central Africa.
The African campaign is central to the WHO's global eradication effort. This aims to prevent any new polio cases worldwide by 2002 and to certify the world polio-free by 2005. However, some public-health experts warn that this goal is over-ambitious.
Having been polio-free for decades, large parts of the globe are now increasingly susceptible to it. Central Africa may act as a reservoir for the disease. Says Bruce Aylward, director of WHO's Global Polio Eradication Initiative: "We can't let this drag on."
Efforts such as these synchronized 'National Immunization Days' (NIDs) eliminated polio from the Western Hemisphere. It was certified free of the disease last October. Given the difficulty of routine access to poor and war-torn areas, Aylward believes NIDs are "the only way forward".
Between today and Monday, around 250,000 health workers and volunteers will oversee the distribution and administration of oral polio vaccine to 16 million children in Angola, Congo-Brazzaville, the Democratic Republic of Congo and Gabon.
WHO workers in the four countries have had to overcome "every logistical hurdle you can think of", says Aylward. They have set up a 'hub-and-spoke' system - distributing vaccines by road or airlift and then carrying them on foot or by boat to remote areas.
Most vaccines will be distributed door-to-door and given to children by volunteers and parents, as previous NIDs have shown that many people cannot travel to local vaccination posts.
Although NIDs have worked elsewhere, access to all parts of central Africa on the same day is impossible. Some people therefore feel that a more long-term and systematic approach is needed.
"I don't for a moment believe there's a prayer they can meet the 2002 deadline," says Donald Henderson of Johns Hopkins University in Baltimore, Maryland, who led the WHO's successful eradication of smallpox.
Henderson fears that if the WHO don't meet the deadline, the opportunity to eradicate polio is in danger of being missed, as WHO funders may become disenchanted and divert limited resources to other areas of public health. He says: "It is critical that [the WHO] be realistic in their goals and expectations and share these regularly and candidly with supporting donors and participants."
Indeed, the WHO will be unable to visit parts of Angola that are under the control of UNITA rebels, where about 20% of Angola's children live. War is the biggest obstacle to vaccination efforts, admits Kandjoura Drame, the WHO's polio eradication coordinator for central Africa based in Kinshasa, Democratic Republic of Congo.
But by working with local leaders and church groups in Angola, says Drame, the WHO has encouraged parents to bring their children to Angola's borders for vaccination. National Immunization Days are the only way to get a foot in the door to many remote areas, he says, and will ultimately increase access.
For the same reasons, the WHO are sticking to their 2002 deadline. Although transient, NIDs are easier to implement than more sustained efforts in areas of conflict. They are highly visible, raising public and political awareness and accelerating other vaccination activities. "Given everyone's commitment, and despite the war, we're confident we can make it," says Drame.
Similar campaigns are scheduled for the same region until 2003.