An 11-year old girl might have been infected with the polio virus because of a decreasing resistance level, said the Director, Expanded Programme on Immunisation, Dr Mazhar Khamisani, on Tuesday.

He said that it was true that the girl belonging to North Karachi had gone to Thatta but she stayed there for two hours only. He said that she was a resident of Godhra Colony where people from other parts of the country live, who might have brought the virus there. He said that the girl had undergone three routine immunisation and five additional immunisation campaigns up to age five.

He said that confirmation of a polio virus case in the city could not be called a failure of the polio campaign. He said that the polio campaign was started at a limited level in 1994 but the house-to-house campaign was launched only in 1999. He said that the final report on the girl would be received within a week.

Meanwhile, the World Health Organisation (WHO) today held a meeting with the health officials about the surfacing of a fourth polio case in Sindh over the last few months. Three cases have been detected in Hyderabad, Nawabshah and Shikarpur, all belonging to the P-1 category. The sources said that the meeting decided to administer polio vaccine to children in the affected areas from May 6-8.The sources said that it was also decided to involve union councils in the campaign.