An Irish Nobel Prize winner has said receiving the prestigious award meant "the end of retirement".
Professor William Campbell, a Trinity College alumnus, was jointly awarded the Nobel Prize for Medicine last year for his work in developing a drug to fight infections caused by roundworms.
The drug, Ivermectin, has almost eradicated river blindness. His discovery has had a massive impact on world health, saving millions of people from diseases caused by parasites.
Professor Campbell was born in Co Donegal in 1930 and studied zoology at Trinity, graduating in 1952. The drug he developed was given away for free by international pharmaceutical company Merck.
"It costs Merck millions and millions of dollars to make a human formulation [of the drug]," Professor Campbell told the Irish Independent.
"The same drug is a huge success in the animal health field. It's a different formulation. It costs millions of dollars to supervise and organise the distribution along with many other agencies and non-governmental organisations.
"It's very difficult to give a drug away, that's what people don't understand. There are problems with policy, precedent settings. It's a very difficult thing to do."
Prof Campbell cites Dr Roy Vagelos, president of Merck, as being "the one person who deserves the credit" for the decision to give the drug away for free.
"He had a handful of close advisers at the top level of Merck management, and between them they decided to do this. But even though there's a little group making that decision, it was Roy Vagelos who had the accountability.
"To my mind it's easy to tell a big drug company to give something away; people love to do that. But if you have no accountability and you have no awareness of how complicated that is, then it's a cheap recommendation."
Prof Campbell was welcomed at a special reception hosted by Trinity Provost Dr Patrick Prendergast, who announced a new lectureship in parasite biology in honour of the scientist.
The scientist also reflected on his time at Trinity College in the 1950s, calling it "a very good experience".
"I read natural sciences and I was especially interested in zoology, and I had the great good fortune of coming under the influence of Professor Desmond Smyth. He changed my life," he said.
Prof Campbell earned a first-class honours degree in zoology.
He also reflected on attending the Trinity Ball, which he called "a big dress-up occasion", and going to the 'Dixon Hop' dances, which he designed posters for on several occasions.
He added that his posters were often stolen by students to put them up on their walls as souvenirs.