U.N. officials said Friday that they were mobilizing to vaccinate 2.5 million young children in Syria and more than 8 million others in the region to combat what they fear could be an explosive outbreak of polio, the incurable virus that cripples and kills, which has reappeared in the war-ravaged country for the first time in more than a dozen years.
The officials said the discovery a few weeks ago of a cluster of paralyzed young children in Deir al-Zour, a heavily contested city in eastern Syria, had prompted their alarm, and that tests conducted both by the government and rebel sides strongly suggested that the children had been afflicted with polio.
The possibility of a polio epidemic in Syria, where the once-vaunted public health system has collapsed after 31 months of political upheaval and war, came as the United Nations is increasingly struggling with the problem of how to deliver basic emergency aid to millions of deprived civilians there.
Valerie Amos, the top U.N. relief official, on Friday told the Security Council that combatants on both sides of the conflict had essentially ignored the council's Oct. 2 directive that they must allow humanitarian workers access to all areas in need. Speaking to reporters afterward, Ms. Amos said she had expressed to council members "my deep disappointment that the progress that we had hoped to see on the ground as a result of that statement has not happened, and, in fact, what we are seeing is a deepening of the crisis."
Bruce Aylward, the World Health Organization's assistant director general for polio and emergencies, which is helping to lead the new emergency effort to vaccinate for polio in Syria, said WHO officials were taking no chances and assuming that the 20 paralyzed children in Deir al-Zour were polio victims. "This is polio until proven otherwise," he said in a phone interview from the group's headquarters in Geneva.
Despite the war, Dr. Aylward said, he believed that both sides understood the urgent need for repeated vaccinations of all young children because polio can spread indiscriminately and is so difficult to eradicate. Nonetheless, he said, it remained unclear whether the vaccination effort in all parts of Syria would be impeded by the conflict's chaos and politics.
"The virus is the kind of virus that finds vulnerable populations -- and the combination of vulnerability and low immunization coverage, that is a time bomb," he said. "There is a real risk of this exploding into an outbreak with hundreds of cases."
The WHO, working with the U.N. Children's Fund and other aid groups, had organized a plan to administer repeated oral doses of polio vaccine in concentric geographical circles, starting with children in Deir al-Zour and eventually reaching western Iraq, southern Turkey, Jordan, Israel, the Palestinian territories and Egypt. In Lebanon, home to more than 700,000 Syrian refugees, public health officials said Friday that they were undertaking a related effort to vaccinate all children younger than 5.
Altogether, Dr. Aylward said, more than 10 million young children in the Middle East would get polio vaccinations over the next several weeks.
The WHO has spent 25 years trying to eradicate polio. In recent years, its presence had narrowed to just three countries -- Nigeria, Pakistan and Afghanistan -- from more than 125 when the campaign began in 1988. The virus is highly infectious and mainly affects children younger than 5. Within a matter of hours, it can cause irreversible paralysis or even death if breathing muscles are immobilized. The only effective treatment is prevention, the WHO says on its website, through multiple doses of a vaccine.
While the precise source of the Syrian polio strain remained unclear, public health experts said the jihadis who had entered Syria to fight the government of President Bashar Assad may have been carriers. Dr. Aylward said there were some indications that the strain had originated in Pakistan. He cited the discovery of the Pakistani strain recently in sewage in Egypt, Israel, the West Bank and Gaza.