Poliomyelitis is a highly infectious disease caused by a virus. It invades the nervous system, and can cause total paralysis in a matter of hours. After initiation of polio eradication programme in 1988 by WHO, number of polio cases abruptly decreased.
In 1988, polio paralyzed nearly 350000 children annually worldwide while in 2007 just 1360 cases reported. The programme has been started in Iran since 1991 and based on high routine immunization coverage, robust Acute Flaccid Paralysis surveillance system and very qualified supplementary immunization activities which has been established and implemented in all the country, number of reported cases decreased from 50 to zero in 2001 and Iran has been polio free since 2001. However due to endemicity of poliomyelitis in Afghanistan and Pakistan (two neighboring countries of Iran) and high level of international traveling between these countries, risk of polio importation and re-emergence of wild polio virus is very high.