Emergency plans are under way to vaccinate more than 20 million children in the Middle East after polio resurfaced in war-torn Syria, the United Nations said on Friday.
Unveiling the region's largest-ever polio campaign, the UN Children's Fund (Unicef) and World Health Organisation (WHO) said vaccinations would be carried out over six months in Egypt, Iraq, Jordan, Lebanon, the West Bank and Gaza Strip, Syria and Turkey.
The initiative was announced 10 days after the WHO reported that polio had re-emerged in Syria for the first time in 14 years, leaving 10 children paralysed.
Preliminary evidence suggests the virus in this outbreak—and also polio samples found in sewage in Egypt, Israel, the West Bank and Gaza Strip—came from Pakistan, one of the disease's last bastions, the agencies added.
"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-immunised children wherever they are," said Peter Crowley, who heads Unicef's polio division.
Inside Syria, the campaign is targeting 1.6 million children with vaccines against polio, measles, mumps and rubella, the agencies said.
More than 650,000 children in Syria, including 116,000 in war-ravaged Deir Ezzor province where the polio outbreak was confirmed, have already been immunised.
"In Jordan, over 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 currently under way to reach 3.5 million people with polio, measles and rubella," the statement said.
"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 later this week and Turkey and Egypt by mid-November."
Polio immunisation hit by war
Polio is caused by a highly infectious virus that invades the nervous system through the mouth and can cause irreversible paralysis within a matter of hours.
Among those paralysed, between five and 10 percent die when their breathing muscles fail to work.
Children under the age of five are those most at risk.
Infection typically occurs through water that carries the virus.
There is no cure for the disease, but there are highly effective vaccines to prevent it.
The 10 polio cases in Syria involved children who had either not been immunised or not received all three doses of the vaccine.
Syria has seen its immunisation rate plummet from more than 90 percent before the conflict began in March 2011 to 68 percent today.
In March this year, health watchdogs celebrated the 60th anniversary of the first successful polio vaccination trial.
But they warned that vaccinations would have to continue so long as a single person still had the virus.
According to WHO figures, polio cases fell by more than 99 percent from 1988 to 2012, from around 350,000 cases to a known 223 cases.
In 1988, polio was endemic in 125 countries, but by 2012, this was reduced to three countries—Afghanistan, Nigeria and Pakistan—where health systems are poor and vaccination campaigns have been disrupted by Islamists.
Experts say polio can spread through so-called asymptomatic carriers.
These are people who have been infected by the virus but do not develop any symptoms of disease. Only around one in 200 people who are infected by the virus become paralysed.
Asymptomatic carriers shed the virus in their faeces, which enters the sewage system, posing a risk for those who are not innoculated or are under-innoculated, especially in areas where sanitation is makeshift.
The European Centre for Disease Control and Prevention (ECDC) has urged European countries to beef up sewage surveillance for polio and to be vigilant about vaccinating Syrian refugees and analysing stool samples
Since the start of the Syrian uprising in March 2011 some seven million people have been displaced, with two million of them fleeing across the border, according to UN figures.
Explore further: Egypt to vaccinate after polio found in sewer (Update)