The WHO's polio challenge: From inspiration to exhilaration

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The World Health Assembly - the forum through which the World Health Organization is governed by its 193 member states - will be meeting in Geneva from Monday through May 23. Among the issues they will discuss is stepping up efforts to eradicate polio. The plan to eliminate the disease was first hatched in 1988, but has stalled in recent years. Bruce Aylward, the Canadian epidemiologist who co-ordinates the WHO global polio eradication program talks with The Globe.

In a word, how would you characterize polio eradication efforts to date - frustrating, inspiring, exhilarating?

Frustrating would not be the word. Inspiring would be closer to it. Exhilarating is what I hope to feel five years after.

But there seem to be so many obstacles.

Sure, there are challenges. Take northern Nigeria: There are real problems, but they're not about polio eradication per se, they're about making a quantum leap in the delivery of public services like health care. Take northern India: We've run into problem, problem, problem. But, again, it's about applying modern science to breaking the back of an ancient virus. We're either over, at or inches from the tipping point but we don't know yet; we'll know in six months.

If things are going well, why do we need a new plan?

The context is that, two years ago, the world assembly looked at the eradication program and said: 'We're deeply alarmed by the situation in Nigeria, and the fact that the last four countries [Nigeria, India, Pakistan, Afghanistan]seemed stalled in their efforts.' So it asked for a new strategy. We suspended our five-year plan and developed a one-year plan.

So how is the new plan?

There are four elements: 1) A recognition that, in Asia and Africa, the immunity thresholds you need to stop the virus are different - they are 10-15 per cent higher in Asia, especially northern India, than in sub-Saharan Africa. 2) We learned that polio can survive in smaller populations and geographic sub-populations than scientists ever thought. 3) We have recognized that the routes of international spread of polio are largely predictable. 4) The last piece of the strategy involved the vaccine itself. Since 2005 we've used new vaccine - type 1 and type 3 - and they've worked really well. But we've seen a Ping-Pong effect: You get type 1 under control and type 3 pops up, and vice-versa. So now we're going to systematically use bivalent vaccines that work well against both remaining viruses.

Are you confident this will get you over the hump?

Just five months into 2010, we're seeing really good results. At this time last year, we had 300 cases of polio in Nigeria; this year, we have two. In northern India, in the states of Bihar and Uttar Pradesh we have not had a single case in four months.

But you have a big outbreak in Tajikistan, which has been polio-free for a long time. It's like a hydra - cut off one head and two more appear.

It's almost like a hydra, but it's not: To kill a hydra you have to cut off all the heads at once. With polio, the challenge is different, it's finding the weak point in the hydra. If you look at a map of the world, every dot you see that is a case of polio originates from eight states in northern Nigeria and two states in northern India. If you stop polio there, there will be no other outbreaks.

But the voices saying "eradication can't work" are growing louder.

There are two groups that control whether or not eradication will get finished. First, there are the countries where infection is still endemic, in particular India and Nigeria. The other group is the G8. That's because 50-60 per cent of the funding for the initiative comes from the G8. The day they decide 'we're not behind this program,' that will be the end of eradication. The good news is that neither group is saying 'No.' On the contrary.

What message would you like to deliver about polio eradication to the G8 meeting in Canada?

They embraced a bold initiative on public health: to get rid of polio and to eliminate inequity in public health. After 10 years of a major investment, they are finally seeing a dramatic result in polio: months and months with very little virus in northern India and northern Nigeria. This is their chance to finish the job.