More than 20 million children are to be vaccinated in Syria and neighboring countries against polio to try to stop the spread of the crippling infectious disease following its re-emergence there after 14 years, United Nations agencies said on Friday.
The mass vaccination against polio, which can spread rapidly among children, is already under way in the Middle East a week after the region declared a polio emergency, the World Health Organization (WHO) and the UN children fund UNICEF said.
Aiming to repeatedly vaccinate about 20 million children in seven countries and territories, it will be the largest-ever consolidated immunization response in the Middle East.
"The polio outbreak in Syria is not just a tragedy for children, it is an urgent alarm - and a crucial opportunity to reach all under-immunized children wherever they are," Peter Crowley, UNICEF's Chief of Polio, said in a statement.
He said the recent outbreak in Syria, confirmed by the WHO last week, should "serve as a stark reminder to countries and communities that polio anywhere is a threat to children everywhere.
WHO spokeswoman Sona Bari said it would take six months of repeated campaigns to reach 22 million children.
"It is going to need quite an intense period of activity to raise the immunity in a region that has really been ravaged both by conflict in some parts, but also by large population movements," she told a briefing in Geneva.
The first polio outbreak in Syria since 1999, it has so far paralyzed 10 children and poses a risk of paralysis to hundreds of thousands of children across the region, the WHO said.
Syria's immunization rates have plummeted from more than 90 percent before the conflict to currently around 68 percent.
Preliminary evidence has indicated the virus is of Pakistani origin, but results of genetic sequencing are still awaited. Polio is still endemic in Pakistan, along with Nigeria and Afghanistan.
Finding the source
"We're never going to know how exactly how it arrived in Syria," Bari said.
"We also know that adults tend to have much higher level of immunity already developed, so it is unlikely that adults brought this it. It is more likely some other route."
Children in unsanitary conditions are particularly vulnerable to infection with the polio virus, which spreads trough faecal-oral transmission and contaminated food and water.
It attacks the nerves and can kill or paralyze, often spreading widely and unnoticed before it starts crippling children. For every case of polio, 200 children can be infected. There is no cure, but it can be prevented though vaccination
Emergency immunization campaigns in and around Syria to prevent transmission of polio and other preventable diseases have vaccinated more than 650,000 children in Syria, including 116,000 in the northeast Deir-ez-Zor province where the polio outbreak was confirmed.
The WHO said the vaccinations were vital in a region that had not seen polio for nearly a decade, but which in the last 12 months has detected the polio virus in sewage samples from Egypt, Israel, the West Bank and Gaza Strip.
Dr. Ala Alwan, the World Health Organization regional director for the Eastern Mediterranean, said what was needed was "a consolidated and sustained assault" on the disease.
UNICEF said it had procured 1.35 billion doses of oral polio vaccine (OPV) to date in 2013 and by the end of the year will have procured up to 1.7 billion doses to meet increased demand.
Global supply of OPV was under pressure with vaccine manufacturers producing at full capacity, the WHO said, and the new outbreak in Syria is adding further pressure. But the WHO, UNICEF and manufacturers said they were are working to secure sufficient quantities to reach all children.
The WHO said the vaccination campaign inside Syria would target 1.6 million children with vaccines against polio, measles, mumps and rubella.
In Jordan more than 18,800 children under the age of five were vaccinated against polio in a campaign in the past few days targeting all children at Za'atari camp, and a nationwide campaign is under way to reach 3.5 million people with polio, measles and rubella.
In Iraq, a vaccination campaign has started in the west of the country, with another campaign planned in the Kurdistan Region in the coming days. Lebanon's nationwide campaign begins this week and Turkey and Egypt by mid-November, the WHO said.