Tokyo’s postponed Olympics is unlikely to take place even in 2021 as the coronavirus pandemic may not be fully contained around the world by then, a growing number of infectious disease experts warn.

The highly contagious virus, which has claimed more than 200,000 lives globally, will be at various stages of spread and infection in different countries by next summer, making it hard to pull off a large-scale international event, some health policy experts say. Under such a scenario, guests and athletes from more than 200 countries and regions would require extensive testing and quarantines -- a logistical process that may not be feasible.

“Japan may be able to contain the virus by next year’s games” but other regions like the U.S., Africa or Brazil may not, creating an uneven playing field for athletes, said Norio Sugaya, a visiting professor at Keio University’s School of Medicine in Tokyo and a member of a World Health Organization panel advising on pandemic influenza. “It’s going to be tough to hold the Olympics.”

Sugaya’s concern is echoed by Yoshito Niki, a visiting professor of infectious disease at Showa University, who warns that the world will need at least two years to contain the virus as infections return in the northern and southern hemispheres when they enter their winter seasons. If the games are to be pushed ahead regardless, spectators would have to be shut out and athletes would have to travel to Japan a month in advance for testing, he said. That raises the question of whether it will be even worth having the event at all, he said.