Emergency declared in Tokyo - What medical experts are saying on hosting the Olympics?

The nation's virus outbreak remains much smaller than in many countries, but a recent uptick in cases has officials and medical professionals worried, even as the government and Olympic organisers insist this summer's Games will go ahead.

"Today we decided to declare a state of emergency in Tokyo, Kyoto, Osaka and Hyogo prefectures," Prime Minister Yoshihide Suga announced, citing the rise of infections involving new virus variants. The measure will run from April 25 to May 11.

The country's minister for virus response Yasutoshi Nishimura earlier warned of a "strong sense of crisis," saying current restrictions were not sufficient.

The measures will be tougher than Japan's last state of emergency, imposed in parts of the country from January, but still far short of the harsh lockdowns seen in some parts of the world.

Initial success in restricting COVID

Japan has had some success containing the coronavirus, with fewer than 10,000 deaths despite never imposing strict lockdown measures.

But cases surged over winter and have rebounded since the previous state of emergency was lifted in March.

Recent outbreak and how it affects Olympics?

Tokyo on Friday logged 759 cases, while Osaka recorded 1,162 new infections, slightly down on record numbers earlier in the week.

Authorities in Osaka have said health facilities there are already overwhelmed and beds for seriously ill patients are running short.

Officials insist the situation will not affect preparations for the Games, with Tokyo 2020 chief Seiko Hashimoto telling reporters Friday: "we're not thinking about cancellation."

"We're thinking about how we can prepare in a way that prioritises safety and makes people feel it can be held safely, and makes them want it to be held."

But the spike in infections is already disrupting everything from the Olympic torch relay -- which has been forced off public roads in several regions -- to test events and qualifiers.

Australia's diving team on Friday withdrew from the Diving World Cup scheduled for May 1-6 in Tokyo, saying it was "not safe" to travel to Japan.

Japan's vaccine programme is moving slowly meanwhile, with just over 1.5 million people given a first shot and only around 827,000 fully vaccinated.

Japan's public remains opposed to holding the Games this year, favouring a further delay or outright cancellation.

What health experts suggest?

The head of the Tokyo Medical Association, Haruo Ozaki, has serious worries about the Olympics however, even if the Games are held with no spectators.

Ozaki says organisers need to show concrete measures on how they can prevent the spread of infection at home and abroad, news service AFP reports.

"If infections spread further, in reality it would be difficult to hold the Olympics in its regular form with athletes coming from various countries, even if the Games are held with no spectators," the Japanese language daily sports newspaper Sports Hochi quoted Ozaki as saying.

At a recent meeting of the Tokyo metropolitan government panel assessing the outbreak, medical experts also voiced their concern about the spread of virus mutations. Their modelling forecasts potential daily infections continuing to escalate and potentially reaching up to 4,000 by mid-May.

"It is best to not hold the Olympics given the considerable risks," Dr. Norio Sugaya, an infectious diseases expert at Keiyu Hospital in Yokohama, told The Associated Press. "The risks are high in Japan. Japan is dangerous, not a safe place at all."

Sugaya believes vaccinating 50-70% of the general public should be "a prerequisite" to safely hold the Olympics, a highly unlikely scenario given the slow vaccine rollout in Japan.

Fewer than 1% of the population has been vaccinated so far, and all are medical professionals. Most of the general public is not expected to be vaccinated by the time the Olympics open July 23.

"Tens of thousands of foreigners are going to be entering the country, including mass media, in a short period of time," Sugaya said, "the challenges are going to be enormous."

The Japanese government and local Olympic organizers have said vaccination is not a prerequisite for the Olympics, although the International Olympic Committee is encouraging the 15,400 Olympic and Paralympic athletes to be vaccinated when they enter Japan.

The number of Covid-19-related deaths in Japan is about 9,000 — far fewer than many countries — but Sugaya stressed the number is among the highest in Asia.

Hospital systems are stretched, especially in hardest hit areas such as Tokyo.

Japan never pushed PCR testing, meaning few mechanisms are in place to prevent infection clusters. There hasn't been a national lockdown, but the government has periodically issued a "state of emergency," urging people to work from home and restaurants to close early.

Dr. Toshio Nakagawa, who heads the Japan Medical Association, expressed serious concern about what he called "a rebound" of coronavirus cases. He called for preventive measures.

"To prevent a fourth wave, we have to act forcefully and extremely quickly," he told reporters earlier this month.

Taisuke Nakata and Daisuke Fujii, professors of economics at the University of Tokyo, have been carrying out projections for the spread of the coronavirus, adapting a standard epidemiological model but taking into account economic activity as measured by GDP and mobility data.

According to their projections, daily infection cases in Tokyo will total more than 1,000 people by May, peaking in July, right about the time the Olympics are on. Daily cases have hovered at about 300 people for Tokyo lately.

They say that's an "optimistic" scenario that assumes vaccines will be gradually rolling out by then.

The other possible scenario has the government declaring a state of emergency as daily cases climb. That could mean the Olympics will be held in the middle of an "emergency." The professors declined to comment directly on the wisdom of holding the Olympics.

Despite the warnings, the Japanese government and Tokyo Olympics organizers remain determined to go ahead with the Games. Tokyo is officially spending $15.4 billion to prepare the Olympics, but several government audits say it might be twice that much. All but $6.7 billion is public money.

The chief driver of the Olympics is the IOC, which derives almost 75% of its income from broadcast rights and needs to get the games on television.

Japanese news agency Kyodo has reported, citing unidentified sources, that 90,000 people are expected to enter Japan from abroad. About 30,000 of those are Olympic and Paralympic athletes, coaches, staff and officials.

That leaves 60,000, and Kyodo said the plan is to cut that to about 30,000, many of whom would be news media. In addition, organizers said all ticket holders from abroad would be banned from entering. Public opinion surveys show most Japanese want the Tokyo Games canceled or postponed again.

Taro Yamamoto, a former lawmaker, said Japan is not prepared to deal with an influx of travelers from abroad. "If Japan has not been able to protect its own people, it cannot claim to be able to protect people from all over the world," during the Olympics, he said. "To keep insisting the Games will go on is just madness."