ISLAMABAD: An aggressive polio vaccination campaign will be conducted in the twin cities’ high risk areas, after environmental samples tested positive for polio in Islamabad and Rawalpindi this year.

In addition, because both the polio cases from 2017 were reported from low risk areas, two nationwide polio vaccination campaigns will be held before the end of May.

Malnutrition will also be raised as an issue, due to the vulnerability of malnourished children to the poliovirus because of their low immunity levels.

When an environmental sample tests positive for polio, this means that the poliovirus has been found in a sample of sewerage from area. A sewerage sample is the basic parameter to see if polio vaccination campaigns have been successful.

A polio case can be reported from any city because of the frequent movement of people from one city to another, but if the virus is found in sewerage it means the local polio vaccination campaign did not meet its target. A position environmental sample also shows that the immunity level of children in the area has fallen, making them vulnerable to the disease.

Two polio cases have been reported this year – one from Lodhran in Punjab and another from Diamir in Gilgit-Baltistan. Meanwhile, environmental samples collected from Sabzi Mandi in Islamabad and Dhok Dalal and Safdarabad from Rawalpindi tested positive this year.

The head of the National Emergency Operation Centre (NEOC) Dr Rana Safdar told Dawn an aggressive polio vaccination campaign will begin in the twin cities’ high risk areas on March 27 following the positive samples.

In response to a question, Dr Safdar said the virus found in a 14 month old in Diamir was of Lahore origin, and had been found in the city in early 2016.

“[The virus] was in low grade and then it shifted to Rawalpindi. The child from Diamir contracted the same virus but, according to our investigation, had never travelled to Rawalpindi. The family travelled to Mansehra in December 2016. The child’s father is a truck driver and he frequently moves in different parts of the country, so there is a possibility that he may have become a carrier of the virus,” he said.

“A large number of people frequently move from Diamir to different areas in the country, so they can also become carriers. [Therefore] it was decided that an aggressive campaign will also be held in Diamir,” he said.

Dr Safdar said that since the poliovirus was also found in Quetta and Karachi this year, and from low risk areas in both cases, two nationwide polio vaccination campaigns will be held during the low transmission period.

The low transmission period takes place during the winter, from September to May, and during this time the poliovirus is less active and can be eradicated more easily.

The oral polio vaccine (OPV) and the inactivated polio vaccine (IPV) will be administered during the nationwide campaigns to “ensure that the virus does not become active during the high transmission season”, he said.

The OPV vaccine contains a live, weak form of the virus that is used to increase the child’s immunity level and prevent the child from being a polio carrier. The IPV contains the dead poliovirus, which keeps a child from contracting the virus but not from being a carrier if the virus is already in the body.

In response to a question, Dr Safdar said the poliovirus is still trying to survive, which is why cases are reported from low risk areas.

“Another reason is that malnourished children become vulnerable to even the low grade virus due to which we have decided to take up the issue with different government departments, to address the issue of malnutrition so that children’s immunity levels stay high,” he said.

Published in Dawn, March 16th, 2017