Poor cold chain facilities linked to Pakistani polio cases
Abdul Wakeel, the assistant director of Pakistan's expanded program on immunization in the Khyber Pakhtunkhwa province, said that the country told the UN body its concerns about the efficacy of the OPV. He said that when people see children getting sick despite receiving the vaccine, they lose confidence in its ability to protect their children, SciDev.net reports.
Wakeel said that it was possible the ineffective batches of live polio vaccine could be the result of poor cold chain maintenance at health facilities. OPV doses must be maintained at between two and eight degrees Celsius from manufacturing to oral administration.
"We procure and supply the vaccine to the health department while the vaccine vial monitors are at stage one," Kamran Sultan, a WHO immunization expert, said, according to SciDev.net. "Further exposure to heat results in their losing efficacy - at stage four they are completely ineffective. The problem may lie in the low education levels of vaccinators who cannot read the VVMs. People associated with immunization campaigns must be trained to examine the VVMs before administering OPV doses to children and reject vials that have been exposed to heat."
Another factor may be the administration of OPV to children whose immunity was already compromised by illness.
"We have been encouraging the health department to ensure that the health status of children is rigorously checked before administering them the vaccine," Shukaib Adnan, an immunization officer with UNICEF, said, according to SciDev.net.
Using OPV, UNICEF, WHO and other international organizations were able to cut polio cases from 350,000 in 1990 to just 250 in 2012.