People of a certain age in the Western World will have haunting recollections of a disease that laid waste to vast numbers of young people. A cruel disease that filled sanitoriums with rows of partially—paralysed children. Polio, a name to strike fear into every parent.

Today, it is a different picture with the disease having been eradicated in most countries, all but defeated by scientific advances in vaccines and a rigorous campaign to administer them that, according to the latest statistics, has reduced incidences by a staggering 99.9 per cent.

Time for a celebration? Well, not quite. Bioscientists and health professionals are a cautious bunch and find themselves loathe to talk about diseases being eradicated because they know that the viruses are simply waiting for an opportunity to make a comeback if we let our guard down.

That is why health professionals constantly caution that the battle against polio is not won.

For all this, the picture is a rosy one with only three countries still blighted by the virus, although a number of others are regarded as at risk should health campaigns falter.

Thirty years ago, according to the World Health Organisation (WHO), polio paralysed more than 350,000 children each year in more than 125 countries. The WHO says that since 1988 cases have decreased to just 37 reported cases in 2016.

Of the three strains of wild poliovirus (type 1, type 2, and type 3), wild poliovirus type 2 was eradicated in 1999 and no case of wild poliovirus type 3 has been found since the last reported case in Nigeria in November 2012.

Nevertheless, according to the WHO, serious challenges remain in the final steps to eradicate the virus, largely caused by weak health systems that struggle to vaccinate every child to ensure high enough protection within a community. This becomes a particular concern in areas including remote locations and those hit by conflict.

Leading the efforts to take those final steps to eradication is the Global Polio Eradication Initiative (GPEI), a public-private partnership led by national governments with five partners, the World Health Organisation, Rotary International, the US Centers for Disease Control and Prevention, the United Nations Children’s Fund (UNICEF) and the Bill & Melinda Gates Foundation.

It dates back to 1988 and the forty-first World Health Assembly, which adopted a resolution for the worldwide eradication of polio. The decision followed the confirmation that smallpox had been eradicated in 1980, progress during the 1980s towards elimination of the poliovirus in the Americas and Rotary International’s commitment to raise funds to protect children from the disease.

In 1994, the WHO Region of the Americas was certified polio-free, followed by the WHO Western Pacific Region in 2000 and the WHO European Region in June 2002.

Twelve years later, in March 2014, the WHO South-East Asia Region was certified polio-free, meaning that transmission of wild poliovirus had been interrupted in a block of eleven countries stretching from Indonesia to India.

The WHO says that the advances mean that 80% of the world’s population now live in certified polio-free regions and that more than 16 million people are able to walk today, who would otherwise have been paralysed. An estimated 1.5 million childhood deaths have also been prevented, through the systematic administration of vitamin A during polio immunisation activities.

However, more needs to be done. For example, contributions and pledges of US$1.2 billion were made at the recent Rotary Convention in Atlanta, USA which was attended by 32, 000 Rotarians from around the world.

A proportion of the money will help WHO in their work to support countries vaccinate 450 million children per year against polio.

Dr Tedros Adhanom Ghebreyesus, Director-General of the World Health Organisation, said: “It is humbling to see again the power of this incredible global partnership to generate funding to fight one of the world’s most horrible and debilitating diseases.

”The new pledges show that donors understand the urgent need to support this mission right through to the very end. We must finish the job properly to ensure that there is no chance of this terrible disease coming back.”

To underline the point, the WHO points to the endemic transmission continuing in Afghanistan, Nigeria and Pakistan.

Failure to stop polio in these last remaining areas puts the world at risk, it argues, and could result within ten years in as many as 200,000 new cases all over the world if left unchecked.

The battle may have been won but there is still a war to be waged before those harrowing pictures of paralysed children lining hospital wards are truly designated to history.