The UN is starting the largest-ever polio vaccination campaign in the Middle East after an outbreak of the disease was detected in Syria.<br /><br />The UN plans to immunise more than 20 million children in seven countries, including Lebanon.<br /><br />While no cases of polio have been reported in Lebanon, half of the country's 800,000 Syrian refugees are children, and many have not been vaccinated against polio since they arrived.<br /><br />Al Jazeera's Zeina Khodr reports from Beirut.
