Authorities in Pakistan have come out with a shocking figure about polio cases. More than 78 percent of such confirmed cases in the country involved children who had been administered polio drops, raising questions about the efficacy of vaccine. According to a report compiled by the National Institute of Health, out of 136 polio cases reported this year, 107 children had been administered polio drops on several occasions under a prescribed schedule, a report said on Wednesday. The data available on the website of the World Health Organisation also indicated that Pakistan had registered the highest number of polio cases in a decade this year. Officials at the National Polio Control Programme said the number of polio cases had increased during the last three years after going down for the previous seven years.