There are many reasons why an athlete may find themselves competing in the Paralympics. They may have been born with a disability; injured in an accident or in conflict, or permanently paralysed by a life threatening disease.
For at least 20 of the athletes who competed in the Games in London this year, it is polio which has left them paralysed - a vicious, highly infectious disease that attacks the nervous system and can cause paralysis, if not death. It is children under five who are most vulnerable to infection.
When I was growing up in the UK in the 1950s, I remember a neighbour affected by polio - there were thousands of cases a year in Britain in the 1940s and 50s, before the polio vaccine was introduced in 1955. But it was possible to watch London 2012's Paralympics Games with a great sense of optimism. These Games were historic, not only for the number of competing athletes and sell-out crowds, but also because they may well have been the last Olympics to take place in a world where a child is at risk of paralysis because of polio. From 350,000 cases in 1988, so far this year there have been only 134 cases worldwide. We are on the verge of eradicating this disease forever.
Ade Adepitan, for many years the face of the GB wheelchair basketball team, now co-anchor of the Channel Four Paralympics coverage, was just six months old when he caught the disease living in his birth city of Lagos, Nigeria.
Polio cost him the use of his left leg and prevented him from ever walking. He, like the 20 athletes competing in London, is living proof that the disease doesn't have to take away someone's life and dreams just because it takes their ability to walk. He is a Paralympics Bronze medallist and World Champion in wheelchair basketball, reaching the greatest heights of his sport.
His achievements also underline the great power of sport in helping children and young people affected by polio to deal with the damage it causes, and rise to the challenges and opportunities it presents. We have been inspired by such resilience, determination and courage day in and day out during the Paralympics.
A key focus of International Inspiration, the London 2012 sports legacy programme, of which UNICEF is a key delivery partner (with the British Council and UK Sport), is to harness this power of sport to reach children with disabilities; to engage them in their communities, underscoring by example the possibility and importance of inclusion. The successes of International inspiration have reached millions of children in many countries around the world.
In Jordan, the programme uses sport to break down virtual boundaries between children in a country where those living with a disability are too often excluded from society. So far nearly 100 NGOs, schools, and organizations for children with disabilities have set up sports hubs in some of Jordan's most deprived areas. Sports coaches have been trained in refugee camps to ensure all children, regardless of ability, are included in sport and play.
This work is literally life-changing, and a real and exciting element of the legacy of London 2012.
Let's be clear, in our current age where a simple, cheap vaccine to protect against polio has been available for over 50 years, no child should still be at risk from the disease. I hope that by the time the Olympics and Paralympics arrive in Rio in 2016 that risk will be gone forever. I hope too that, thanks to the power of sport, the London 2012 Paralympics will mark a milestone in inclusion of people who are disabled, whatever the cause.
India, the epicentre of polio just a few years back, and the place where five of the affected 2012 Paralympians were born, is the latest country to make the disease history. It was officially declared polio free on 25th February 2012.
This leaves just three countries still trying to eradicate the disease; Nigeria, Afghanistan and Pakistan. They face a number of challenges - pockets of opposition to immunisation programmes, re-infection across borders and ongoing security issues - but these barriers are not insurmountable if funding and focus remains.
With global cases of the disease at their lowest levels since records began, and limited to fewer districts, within fewer countries than ever before, the world has a unique window of opportunity to eradicate it completely. In the words of Bill Gates; "if we all have the fortitude to see this effort through to the end, then we will eradicate polio."
If the inspirational athletes of the Paralympics can achieve so much, against such enormous odds, surely the human race can unite to reach those few remaining districts and make a final push to wipe out polio and achieve one of the greatest ever victories for humanity.
If so, then by the time we are celebrating Rio 2016, we will live in a world where no child will have to face the permanent damage which polio can bring. Then, in the years that follow we will see Paralympic Games which are equally inspiring, but in which the legacy of this vicious disease plays no part.
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