There is an inevitability with the seasoned demographic of Rotary that we will ​lose good friends who pass on to higher service.

However, it was a shock to receive the news in August that Aidan O'Leary, the ​Dublin-born Director of the World Health Organization's Polio Eradication ​Programme, had suddenly died.

Aidan, whose family are based in Galway and who had close connections with ​the Rotary Club of Galway-Salthill, died while on holiday with his family. He was ​just 59.

Such was the impact of Aidan's death that the Irish President, Michael D. Higgins, ​described the softly-spoken Irishman as "a wonderful person who dedicated his ​life to helping those living in the most difficult, war-torn parts of the world".

I met Aidan several times during his three-year tenure in the role, succeeding the ​equally formidable Michel Zaffran. Though Aidan's time in the role was short, he ​made a considerable impact.

Polio and the bid to eradicate the disease from the face of the planet is built ​around considerable science. Aidan's great gift was breaking down the ​complicated science, without god-forsaken acronyms, into easily accessible ​chunks which everyone could understand.

He described what research was being undertaken, he told what was happening ​with vaccinations in remote villages in Afghanistan and Pakistan, outlined the ​diplomatic gymnastics being performed to get the vaccinators on the front line to ​the children, and pulled no punches when pointing out the challenges which lay ​ahead.

Last September, at the Rotary Action Summit in Manchester, Aidan delivered a ​stunning update on the polio campaign which received a standing ovation. It was ​brilliant. Afterwards, he sought me out. "What did you think?" he asked. "I think ​the ovation afterwards said it all," I replied.

Rotary's End Polio Now campaign stands at an important crossroads focussed on ​the final two hot spots in Afghanistan and Pakistan, while tackling the fall-out in ​Gaza. One of the last projects Aidan was working on was preparation for two ​rounds of polio campaigns in Gaza, targeting 600,000 children under the age of ​eight.

Next year will be 40 years since Rotary launched its PolioPlus campaign. There is ​inevitable talk of polio fatigue after Rotarians have contributed more than $2.1 ​billion and countless volunteer hours to protect nearly three billion children in ​122 countries from this paralysing disease.

This issue of Rotary Digital coincides with World Polio Day on October 24th by ​highlighting the stories of polio survivors in Great Britain and Ireland. Theirs is ​the lasting legacy.

This issue of Rotary Digital is dedicated to Aidan O'Leary; an amazing, yet humble ​man, who was passionate about polio. His loss is at this critical time is immense.

I once posed a question to Aidan that if he was a betting man would he put his ​money on polio being eradicated within his lifetime. "I would be confident," he ​replied. "A polio-free world is within reach. There is an opportunity, and now is ​the time to stay on course."