Kabul, Oct 14 (IANS): Afghan health authorities on Monday launched an extended sub-national immunization campaign to give polio immunity vaccination dose to 8.5 million children under five years old.

"The five-day campaign targets over 8.5 million children under 5 years of age in 324 districts across the country. The campaign is launched in most of the places where limited children were reached earlier in the year," Xinhua news agency quoted the Ministry of Public Health as saying.

"We are concerned that following the long pause in polio vaccination in parts of the country, more children have become vulnerable to poliovirus, therefore it is of paramount importance that we vaccinate those who have been missing out," it added.

The Ministry called on the parents to protect their children against polio by letting the vaccinators get in when they come knocking on the doors.

The ongoing insurgency and conflicts have been hindering the efforts to curb the infectious disease in the mountainous country as 1.2 million children from inaccessible areas have missed previous drives.

There are only two countries in the world, Pakistan and Afghanistan, where polio cases are still reported.