A leading global health scientist has said holding the Tokyo Olympics in 2021 would be "very unrealistic" without an effective vaccine for the new coronavirus, the BBC reported Friday on its website.

Devi Sridhar, the chair of global health at the University of Edinburgh, said the timely development of a vaccine would be necessary for the games to go ahead as now scheduled from July 23 to Aug. 8 next year, a one-year postponement due to the coronavirus pandemic.

(Devi Sridhar)[Getty/Kyodo]

"If we do get a vaccine within the next year then actually I think that (the Olympics) is realistic," the professor said. "The vaccine will be the game-changer -- an effective, affordable, available vaccine."

"If we don't get a scientific breakthrough then I think that looks very unrealistic."

On Thursday, John Coates, the head of the International Olympic Committee's coordination commission, told a press conference that it is still "too early to say" if the outbreak could further impact the games, including another delay or banning spectators.

Related coverage:

Olympics: Narasaki goes back to basics in bid for sport climbing gold

Olympics: Japanese wrestler using lockdown to lock in mental fortitude

Olympic torch designer shares DIY face shield with health care workers