“We’ve been working very closely with the authorities in Qatar on that as WHO, and providing advice as needed to them on how to run a safe World Cup.
“The public health authorities in Qatar have been very engaged… on the public health risk management of the World Cup.
“Overall, the risks are being very carefully managed.”
Two million tickets will be sold in total, with another one million reserved for sponsors and the sport’s global governing body FIFA.
The Qatari capital Doha, with a population of about 2.4 million, is bracing itself for the huge influx of visitors.
“I don’t perceive there’s any more risk with the World Cup than there’s been with any other mass gatherings,” said Ryan.
“I have every faith that they will be able to run a successful World Cup and that it will be a spectacle for the world to enjoy.”
The 32-team tournament set to be the most geographically-concentrated World Cup in history kicks off on November 21.