An unprecedented vaccination campaign has produced strong results in fighting polio in India and if sustained, the crippling disease could be eradicated in the next two years, a top WHO expert said.

Although India overtook Nigeria with the most cases in the world this year, the rise was of a less virulent strain and authorities should not divert their focus from rooting out Type 1 polio, Bruce Aylward, director of WHO's Global Polio Eradication Initiative, said.

Polio, which is incurable, leads to irreversible paralysis. Death occurs in about 5-10 percent of paralyzed patients when their breathing muscles are immobilized.

Overall, India had 367 cases this year compared to 593 in the same period in 2006, WHO data, compiled in collaboration with Indian health authorities, showed. Of this, Type 1 accounted for a mere 66 cases compared to 575 last year.

This is the biggest thing to happen in the program. No one would have believed India would be here in October, Geneva-based Aylward told Reuters. This is a surprise.

Eighty-five percent of your kids are protected. You've got almost zero polio for 11 months in the core area, unprecedented, he said in an interview late on Wednesday. This has never happened before.

If you finish Type 1 at the end of 2008, that's victory. Type 3, mop it up in 2009 if you have to, that's still victory, he said.

Since the WHO eradication drive began in the late 1980s, cases have dropped from 350,000 in more than 125 endemic countries in 1951 to 695 so far this year, the lowest in years. India has said it hopes to wipe out the virus by the end of 2008.

The virus is transmitted through the fecal-oral route in unhygienic conditions. It enters the intestine and multiplies there if food is eaten with unwashed hands.


India, along with Nigeria, Pakistan and Afghanistan, is among the last hotspots for the disease and a spike in cases in India in 2006 had sparked global alarm.

A change in strategy to focus first on the virulent Type 1 strain in the most vulnerable northern states of Uttar Pradesh and Bihar, and increase the frequency of immunization to cover as many children as possible, was paying off, said Aylward.

While Type 1 paralyses around one out of every 200 infected children and travels over wide areas, Type 3 paralyses one in around 1,000 infected children and does not travel so far.

The density of populations in Uttar Pradesh and Bihar and poor living conditions made the task of eradication especially difficult, Aylward said.

There are big risks, the Canadian epidemiologist said at the end of a tour to Nigeria, Pakistan, Afghanistan and India. When you're doing something this big, there's a tremendous temptation to stop as soon as possible and that's where people make mistakes.

While Uttar Pradesh needed to focus on Type 1 and not worry too much about its higher Type 3 cases, Bihar needed to go after the Type 1 in remote villages along river embankments and immunize children who are difficult to reach, he said.

The last few cases are the toughest because you are trying to get out to the populations that always get left behind for everything, you are trying to put a face on the kids that nobody ever sees, the population nobody ever knows, the governments, quite frankly, everyone, fail.