The worldwide campaign to eradicate polio, which is a whisker from total success, is being threatened by northern Nigerian states that claim the vaccines are part of a sinister Western plot to sterilise African girls.
Politicians and radical Muslim clerics in Kano and Zamfara states have banned World Health Organization polio vaccines, which they insist could help spread HIV and contain hormones that cause infertility. Last week the Nigerian government published a study that refuted their claims. A day later, the Kano government reiterated its ban.
The row has dealt a blow to a massive, 16-year WHO immunisation campaign, and has already taken a human toll. Over 400 Nigerian children have contracted polio since September, according to the UN. The virus has spread to eight nearby countries where it had previously been eradicated. Ivory Coast, for instance, last month reported its first case since 1999.
Elsewhere, the WHO is tantalisingly close to its goal of wiping polio from the face of the Earth. Since 1988 it has immunised two billion children in 200 countries, sending infection rates plummet- ing from 350,000 per year to 782 last year. Now the crippling disease is cornered in eight strongholds - Niger, Afghanistan, Pakistan, India, Egypt and Nigeria, which accounts for half of all cases.
Eradicated from the West in the 1950s, the polio virus now survives in the poor sanitary conditions of the developing world. It mostly attacks children under three, about one in 200 of whom develops the disease. It causes irreversible disability - shrivelled and disfigured limbs, paralysis and, in some cases, death. But it can be easily prevented.
The polio vaccine is cheap - just 6p a shot - quick and effective. Health workers open an infant's mouth, draw the vaccine from an icebox, and squeeze two drops on to the tongue. Against the odds, the campaign has penetrated some of Africa's most bedevilled trouble spots. In Somalia, health workers negotiated one-day truces with rival warlords to administer the drug. Last year in the Democratic Republic of Congo, 25 immunisers were kidnapped by militiamen who accused them of being enemy spies. The Angolans had to wait for the death of rebel leader Jonas Savimbi before acting.
As a result, not one new case of polio has been reported in 22 countries across eastern and southern Africa since October 2002, said Robert Davis of the UN Children's Fund (Unicef) in Nairobi. But apart from a £70m funding gap, the main stumbling block remains the stubborn leaders of northern Nigeria. As the WHO launched an emergency vaccination campaign targeting 63 million African children last month, state officials in Kano said they had found scientific proof that the vaccines contained oestrogen and progesterone, female sex hormones that could cause infertility. The claims were backed by Jama'atu Nasril Islam, an influential Muslim group. One leader said: "We believe that modern-day Hitlers have deliberately adulterated the oral polio vaccines with anti-fertility drugs and contaminated [them] with certain viruses which are known to cause HIV/Aids." The UN rejected the claims as baseless - the claimed oestrogen levels were less than that of Western drinking water - and the Nigerian President, Olusegun Obasanjo, later sent a team of health officers and Muslim leaders to South Africa, India and Indonesia to investigate.
They gave the vaccines a green light on Wednesday, but the Kano state government reiterated its ban, saying it would only source vaccines from "internationally recognised pharmaceutical companies".
Nigerians have reasons to be wary of Western medicine. In 1996, the US pharmaceutical giant Pfizer carried out trials of a meningitis drug. Patients said they were not properly informed of the side effects, and a disabled group is currently bringing legal action in the US. And in the late 1990s author Robert Hooper controversially claimed that the HIV virus was spread through a defective polio vaccine administered to a million women and children in Belgian Congo between 1957 and 1960. "They didn't pull these concerns out of thin air," admitted Oliver Rosenbauer, a WHO spokesman in Geneva.
But the true origin of the standoff may be more mundane. Northerners, who once dominated Nigeria's government, have been jockeying for position in the Christian-led administration. They established Sharia law as a challenge to President Obasanjo; two years ago they fomented violent riots during the Miss World beauty contest. Many of the same voices of the Sharia controversy are also prominent opponents of the vaccine.
Nigeria's next round of immunisation is due to start tomorrow. The WHO is waiting to see if the governors of Kano and Zamfara accept the findings of the team. The Sultan of Sokoto, a senior Islamic figure, has already endorsed it. The fate of hundreds of potential victims, too young to decide for themselves, depends on whether others will follow.