Medical experts have warned pinning hopes on vaccinating athletes alone is not the solution to guarantee being able to stage the rescheduled Olympic Games in Tokyo this year.

With the Games due to commence in less than six months, the distribution of Covid-19 vaccines has featured significantly in discussions about whether the Tokyo Olympics can be held safely.

Experts, however, believe organisers should prepare for the Olympics regardless of any possible vaccine roll-outs, and have recommended they instead have enough polymerase chain reaction tests to conduct on athletes, coaches and staff on a daily basis.

Last week, reports emerged that the International Olympic Committee were working with the World Health Organisation to ensure all Olympic-bound athletes were vaccinated.

However, the WHO has since reaffirmed that Olympic athletes should not be given priority for vaccinations, a stance recently supported by Brenda Dale, the vice-president of the Bermuda Olympic Association and chef de mission for Tokyo 2020.

Whether or not athletes are vaccinated ahead of arriving for the Games — set to commence on July 23 — as recommended by the IOC, medical experts have warned it would not be ideal to prepare for the Games under the assumption vaccines will be available for athletes.

“It’s only a problem for those who are associated with the Olympics,” said Tetsuo Nakayama, a project professor at Kitasato Institute for Life Sciences and director of the Japanese Society of Clinical Virology, in a statement released to the media in Japan.

“When it comes down to the Olympics, it’s not just the athletes who are participating but others — like people who support the athletes and people working at the Athletes Village.

“I think it’s strange to think of hosting the Olympics assuming there would be vaccinations for all those people.”

Another potential issue raised by Nakayama is whether athletes will want to be vaccinated with some uncertainties surrounding the long-term side effects.

He added: “Would they want to be vaccinated knowing they’re not 100 per cent safe? It’ll be up to each athlete to think about.”

More than half of Japan's population is under a state of emergency as a result of a sudden surge in cases last month, while the vaccination process is set to start in Japan only this month.

Tokyo reported 393 new Covid-19 cases yesterday and, despite that figure being the lowest daily tally since December 21, Nakayama believes that even if numbers continue to fall and vaccinations are distributed, it will not be enough to guarantee safety at the Games because vaccines alone will not achieve a required level of herd immunity in the capital city.

However, despite his concerns, Nakayama actually believes Tokyo can host the event safely even without vaccines by implementing detailed protocols and countermeasures against the virus.

“What’s most important is to arrange a safe situation — where you have athletes and everybody else that’s coming from overseas — to host the Games,” Nakayama added. “The discussions of the vaccines should come after that.

“If the Games are to be held, you have to come up with the situation that will ensure safety, by doing PCR tests for those closely associated with the event. It’s not like there’s no risk you’ll be infected after being vaccinated.

“If you can prepare a system where the participants will be tested every day, you can host the Olympics. If you’re careful, such as by not allowing the athletes to have meals together and giving them PCR tests every day, I think it’s possible to lower the chance of infections during the Games.”

Meanwhile, for the first time Olympic organisers have conceded they have been preparing for a scenario where the Games may have to be held without spectators.

"We have been doing all kinds of simulations,“ Yoshiro Mori, the Tokyo Olympic Organising Committee chairman said in a virtual meeting with IOC president Thomas Bach. ”Basically, I don't think the Games without fans is something that would happen or something that I would like to do, but it won't be a simulation unless we think about it."

Mori is set to hold further discussions with Bach and Olympic Minister Seiko Hashimoto this month to prepare for the Games. The organising committee is looking at various scenarios and running simulations to understand how the event could play out under different circumstances.

At present, three options are being considered for the Olympics:

• Having no limit on the number of spectators

• Imposing a 50 per cent cap on spectator numbers

• Running the events without spectators

Decisions on the matter are expected within the coming months, including the number of spectators permitted into each venue, if allowed, and whether to admit fans from overseas.