Tokyo, Japan – With less than 100 days to go before the scheduled opening of the postponed Tokyo Olympics, Japan is witnessing the emergence of a fourth wave of the COVID-19 pandemic which some fear will dwarf the previous three.

Much to the government’s chagrin, daily coronavirus cases have been on the rise since early March and this week began to cross 4,000 infections a day.

In the 15 months since Japan recorded its first case of COVID-19, there have now been more than 500,000 confirmed infections and nearly 10,000 deaths in the country.

The government of Yoshihide Suga, however, appears determined to host the Tokyo Olympics after the initial one-year delay, and has attempted to downplay the seriousness of the current crisis. It has refused to declare a third “state of emergency.”

But with case numbers swelling and the increasing inability of some regions’ hospitals to cope, some health experts are now speaking up.

Part of the pressure is coming from the nation’s medical leaders, who are voicing concerns despite the administration’s reassurances.

Japan Medical Association President Dr Toshio Nakagawa declared on Wednesday that “an early emergency declaration is necessary” in order to stem the spread of the coronavirus.

Dr Haruo Ozaki, the chairman of the Tokyo Medical Association told a local newspaper separately that “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 government’s own top medical adviser, Dr Shigeru Omi, testified to a parliamentary committee this week that “there is no doubt that Japan is entering the fourth wave of infections.”

As of midweek, however, Prime Minister Suga was still trying dismiss such talk, telling the House of Councillors that “new infections have yet to become large waves nationwide.”

But the very next day, his position was undermined by the ruling party’s number-two official, Toshihiro Nikai, who told a television programme that the Olympics might yet need to be called off. “What’s the point of the Olympics if they become responsible for spreading infections?” he asked.

Restrictions imposed

Meanwhile, even as the national government continues to resist calls from the medical community to declare a formal state of emergency, it is gradually expanding the scope of what it now calls “quasi-emergency measures.”

These measures, such as clamping down on nightlife by requiring bars and restaurants to close earlier in the evening, are essentially identical to the state of emergency measures that had been imposed in some regions previously.

The only difference is that they are now backed by the power to impose fines on those who fail to cooperate.

As of Friday, such “quasi-emergency measures” had been authorised in 10 of the nation’s 47 prefectures, including in all of the largest urban centres.

But the restrictions may not be enough to slow the outbreak and experts are pointing to two key reasons why Japan’s fourth wave of COVID-19 could easily become larger than the previous three ones.

The main epicentre of past coronavirus waves was in Osaka Prefecture. But this iteration now threatens Tokyo, Japan’s most populous area. This western prefecture is currently recording more than 1,000 cases on a daily basis – a number that it had never previously hit. The surge has already forced the cancellation of the torch relay there.

It is thought to be only a matter of time before the record-smashing case numbers in Osaka reach Tokyo and other parts of the nation.

Driving these concerns is the second distinctive point about the current wave – most of the new cases in Osaka appear to come from the more infectious COVID-19 variants, rather than the initial version of the virus that fuelled previous waves.

At a Tokyo Medical Association news conference on Wednesday Deputy Chairman Masataka Inokuchi said: “There’s a significant chance that Osaka is the Tokyo of two to three weeks from now.”

Association Chairman Ozaki expressed particular concern about the so-called N501Y mutation, which has already taken hold in the Japanese capital region.

“N501Y is very infectious,” Ozaki warned, “and it’s being said that young people, who were previously not easily infected, are now contracting the virus. It’s important that people of all generations consider getting back to the basics on infection prevention.”

Sluggish vaccination programme

Residents are bracing for tougher public policy measures.

Stephen Zurcher, the dean of Asian Studies at Kansai Gaidai University in Osaka, told Al Jazeera that although his university has only just resumed a policy of allowing students back into the classroom as part of a “hybrid” teaching model, they also know that conditions in the region may soon force them back to a purely online format.

“If [Osaka Governor Hirofumi Yoshimura] does decide to go to a full state of emergency and tell people and students to stay home, then of course the school would shut down. We’d have no choice. We’d immediately flip out of this hybrid strategy and move directly to all instruction occurring online,” he said.

Japan can expect little near-term relief from COVID-19 vaccines either.

Although the nation has acquired millions of doses of the Pfizer-BioNTech shot and will be offering it without charge to all residents, its vaccination programme has been disappointing.

The national government had earlier insisted that the vaccines needed to be tested on ethnic Japanese before granting legal approval. And coordination between ministries and local governments has continued to be sluggish.

The net result is that despite the urgency of preparing for the Olympics, having a national healthcare system and the appointment of a capable minister to oversee the programme – Japan is far behind other advanced nations in getting the vaccine to its people.

So far, less than 1 percent of Japan’s population has received a vaccination, compared with more than 47 percent of the population in the United Kingdom and 37 percent in the United States.

As a result it will be too slow to decisively affect the country’s plans to host the Olympics or hamper the trajectory of the threatening fourth wave.