Pakistani polio victims traced to weakened vaccine

According to health authorities in Pakistan, over 78 percent of the confirmed polio cases in the country have been in children who were given polio drops.

The National Polio Control Program said that the number of polio cases has increased the last three years after having previously gone down for seven consecutive years, reports.

Officials believe that the vaccine may have lost its efficacy after it was not stored at the necessary temperature, especially in areas where electricity can be disrupted for many hours at a time.

"Vaccine failure and failure to vaccinate are two important factors which have affected the national polio campaign," Professor Athar Niaz Rana, head of the allergy and immunology department at the Shifa International Hospital, said, according to "The problem of vaccine storage in areas where refrigeration facilities are not available or power supply is discontinued very frequently also affects the efficacy of polio vaccine."

A health ministry official told that the vaccine, which has been tested by the World Health Organization, is not at fault, and that the management and security issues surrounding the use of the vaccine are more to blame. The official said that they a comprehensive plan has been developed for 2011 to reverse the recent trend.