ISLAMABAD: Pakistan today formally launched a new polio vaccine, an important step to accelerate its polio eradication campaign as the authorities vowed to wipe out the disease by 2016.

More than four million children will benefit from the inactivated polio vaccine (IPV).

Pakistan is one of three countries in the world where polio remains endemic. Nigeria, which recently marked one year without a case of wild polio, introduced IPV earlier this year and Afghanistan is due to begin using it in the coming weeks.

Pakistan has made substantial progress in reducing the crippling childhood disease, with only 29 cases reported so far this year, compared with 115 in the same period in 2014.

Saira Afzal Tarar, Pakistan's deputy health minister, hailed the IPV introduction as a landmark.

"We are hopeful that we will intercept the virus by 2016," she told.

The injected vaccine is more expensive than the OPV and needs a nurse or doctor to administer it, but needs only one dose to ensure immunity, unlike the oral vaccine which is administered several times.

Doctor Lamia Mahmoud of the World Health Organization (WHO) said IPV was an important tool to bolster the immunity of infants against poliovirus, especially those who have not had adequate opportunities to receive the oral vaccine.