He had a full course of polio vaccinations, including three doses of
weakened live virus at five, seven and 12 months old, followed by a
booster when he was about seven.
He had an immune disorder that mean the weakened polio virus used to vaccinate him in childhood survived in his body.
Over time it has mutated into a form of the virus that can cause paralysis and he had no idea the jab had not worked.
The discovery was made by a team from the National Institute for Biological Standards and Control in Potters Bar, Hertfordshire.
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