Wiffen took part in the men's 10-kilometre marathon swim in the River Seine on Friday, finishing 18th with a time of 1 hour 58 minutes. However, the athlete did not link his illness to the river water. Moreover, the organisers insist that health problems should not automatically be attributed to the river, but may be due to other factors unrelated to the state of the Seine.

This came as a surprise because he was due to carry the Irish flag during Sunday's closing ceremony, but failed to turn up. In response, he issued the following statement on Monday morning, Monday 12. "Thanks to everyone who has contacted me, I am very disappointed not to have had the opportunity to be the flag bearer last night," Wiffen wrote on X. "I rushed to the hospital yesterday because I was very ill with a virus that I am being treated for, and I am feeling better now.

Shortly after this was published, Paris Olympics organisers wished Wiffen "a speedy recovery", but said they were not aware of "any established link between the illness and the quality of the water in the Seine".

"The water quality on the day of the men's marathon swim was considered 'very good' or 'excellent' at all four testing points and within the thresholds set by World Aquatics," the organisers said in a statement, trying to avoid confusion and misinterpretation. And it is that The Seine was beset by pollution problems during the Olympics, despite a €1.4 billion renovation to improve Paris' sewage and water treatment system.

There are already three athletes who announced they had fallen ill after swimming in the River Seine. Among them was Belgian triathlete Claire Michel, who also needed medical attention after suffering three days of vomiting and diarrhoea due to a virus.