Bruce Aylward: "NIDs are usually the largest health activities a country ever sees"

The campaign concentrates on mass vaccinations, or National Immunisation Days (NIDs), which aim to vaccinate every single child in a specific population on two separate days, one month apart.

The second component of the campaign is to put in place surveillance systems to discover where the virus is located at any particular time in order to target supplementary immunisation programmes.

There is no cure for polio, which is highly infectious, but, given a few drops of vaccine, children - the main sufferers of the disease - can be protected for life.

Angola outbreak

1999 World Health Assembly gave programme unanimous backing

Since the polio immunisation scheme was launched in 1988, the disease has been removed from vast areas of the developing world. But it remains active in south Asia and sub-Saharan Africa.

The accelerated efforts to consign the virus to the history books come in the wake of Africa's largest ever recorded polio outbreak, in Angola.

The disease attacks only humans and immunity is life-long, so it is hoped the virus will simply die out as a result of being deprived of human hosts.

'Tranquillity' days

The co-ordinator of the WHO campaign, Bruce Aylward, says its success depends on the willingness of communities to participate.

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But there is a particular problem in gaining access to people in regions affected by war.

The programme will concentrate on six countries which are the scene of current conflicts: Angola, the Democratic Republic of Congo, Sierra Leone, Somalia, Afghanistan and Tajikistan.

So-called "Days of Tranquillity" in these countries, agreed between warring factions and armies, are intended to allow NIDs to go ahead.

The programme will also focus on other countries where the disease is concentrated: Bangladesh, Ethiopia, Nigeria, Pakistan and India - the country where the majority of child polio cases occur.

Reasonable deadline

The resolution to accelerate the immunisation campaign was agreed in May at the World Health Assembly, when 46 countries pledged to meet the 2000 target.

British pop star Robbie Williams helped out in Sri Lanka's last NID

Mr Aylward says the campaign demonstrates a "whole new way of working" between governments, NGOs and private donors.

For example, the global diamond cartel De Beers is meeting one-quarter of the cost of the Angola immunisation day this year and in 2000.

If the 18 month time-scale sounds optimistic, Mr Aylward cites the example of global success in the fight against smallpox, which was declared in 1979.

He says the disease was eradicated in India within 12 months, when the government decided to raise awareness about immunisation programmes.