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Polio battle won, war not over

New Delhi, Feb. 10: India will celebrate three years without a single case of polio caused by the wild poliovirus on Tuesday, but public health experts have said the “endgame” to eradicate polio from the country will begin only next year and might last until 2018.

The Union health ministry has planned a celebratory event at a stadium here, inviting India’s political leaders, World Health Organisation (WHO) officials, international agencies, and over 1000 field workers — doctors, vaccinators, and state health officials, all key players in India’s victory over polio.

India’s poliovirus surveillance network has not detected any case of paralysis caused by the wild poliovirus since a two-year old girl from Howrah district in Bengal developed polio in January 2011. A country becomes eligible to receive polio-free certification from the WHO after a period of three years without the wild poliovirus. Health officials expect India to be get the polio-free label from WHO in March this year.

“We’re on the eve of a big celebration — this is very significant,” said Nicole Deutsch, chief of the polio programme at Unicef, a UN agency that has guided India’s war on polio that began with the introduction of universal polio immunisation in 1985.

Public health experts estimate polio caused by the wild poliovirus used to paralyse about 200,000 children each year during the 1980s. The immunisation programme, using the oral polio vaccine (OPV) made from live but weakened versions of the virus, helped reduce the number of polio cases and eventually eliminated the wild poliovirus.

Health officials, guided by senior WHO experts, had to tweak the polio eradication strategy at least twice -- launching nationwide mass immunisation campaigns in 1995, and introducing new versions of the OPV over the past decade — to get rid of the wild poliovirus.

In a typical mass immunisation campaign, over two million vaccinators would visit some 200 million households across the country and immunise 170 million children below five years. Children in transit would receive the polio drops in trains, at railway stations, and in market places.

“Polio control is among India’s best-executed public health programmes,” said Anis Siddique, a polio programme specialist with Unicef. “But India needs to continue with rigourous surveillance and immunisation because there is a risk of India importing polio.”

While Afghanistan, Nigeria, and Pakistan still have wild poliovirus circulating in their populations, Ethiopia, Kenya, Syria, and Somalia have reported cases of imported polio.

India’s three years without wild poliovirus is widely hailed as a landmark achievement, but senior public health experts point out that the country has yet to deal with the risk of polio paralysis that results from the use of OPV.

During 2013, five children developed vaccine-derived poliovirus (VDPV), an infection caused by an OPV virus that has regained its ability to cause disease. Public health experts also estimate that about 100-180 children develop vaccine associated polio paralysis, a rare but serious side effect of OPV, each year.

“This is a political celebration,” said Thekekkera Jacob John, former head of virology at the Christian Medical College, Vellore, who has been tracking wild polioviruses in India since the mid-1970s and had suggested that OPV alone might not be able to eradicate polio. “The second phase of the endgame to completely eradicate polio by eliminating the vaccine viruses from India is yet to begin,” John told The Telegraph.

The WHO has pencilled what its officials have called an “endgame” strategy that involves using an alternative, injectible polio vaccine (IPV) that is made from killed viruses that cannot cause any harm to children with low immunity or to vaccine recipients.

The endgame strategy, a senior official with an international agency said, envisages the introduction of IPV in 2015 with a gradual phase-out of the OPV vaccines over the next three to four years with the goal of global eradication of polio by 2018. While IPV has been used in India’s private health care sector for over five years, a senior official with an international agency said India is expected to introduce IPV in the free routine immunisation programme in 2015.

But Ajay Khera, deputy commissioner for immunisation in the health ministry, told this newspaper that the endgame strategy is under discussion. “The government is still examining the logistics of procuring and delivering IPV through the public immunisation programme,” another health official said.

About 27 million babies are born in India each year, and the IPV is ideally given in three doses at six, ten, and 14 weeks after birth. John, who has in the past chaired a technical group that advised the Indian government on polio eradication, said Indian manufacturers have assured supplies of IPV.

“All countries that use OPV will have to eradicate polio in two phases — wild poliovirus eliminated by OPV, and the vaccine viruses eliminated by IPV," John said. “The immunisation programme has no choice but to introduce IPV — the sooner in 2015, the better.”