What appears to be a fourth wave of COVID-19 is materializing in Japan mere weeks after the country began easing virus countermeasures.

There were concerns that beginning to lift the state of emergency in early February in the nation’s most populated regions would trigger a viral rebound, but perhaps not so soon or in so many parts of the country.

The resurgence is most pronounced where the order was lifted in early February, which implies the unsettling possibility that in the greater Tokyo metropolitan area — where the declaration was ended weeks later on March 22 — a delayed uptick is quickly approaching.

As the central government weighs stiffer restrictions, regional leaders have already begun to sound the alarm.

On Wednesday, Osaka Prefecture reported 599 cases of COVID-19, the highest one-day figure since Jan. 23.

Of the country’s 47 prefectures, 34 saw a significant jump in new cases between March 21 and 28 compared with previous weeks, most notably in Miyagi, Aichi, Hyogo, Okinawa, Osaka and Yamagata prefectures, as well as in Tokyo.

“We have entered a fourth wave,” Osaka Gov. Hirofumi Yoshimura said Monday, outlining his plans to submit a formal request to the central government to designate Osaka an area in need of stricter virus measures in accordance with a legal amendment passed in February. That would give him the ability to impose monetary fines on businesses that fail to comply with repeated requests to close early and a subsequent order to do so.

Those measures could take effect in Osaka as early as Thursday, according to media reports.

Aichi Gov. Hideaki Omura said Monday that new cases are rebounding “without a doubt,” while Miyagi Gov. Yoshihiro Murai said the prefecture has no more hospital beds to spare for COVID-19 patients.

The state of emergency — which was declared in early January in 11 prefectures, then extended in all but one place, Tochigi Prefecture — was lifted in six prefectures in early February, including Osaka.

The order wasn’t lifted in the remaining locations — the capital and the neighboring prefectures of Kanagawa, Chiba and Saitama, which together comprise the greater Tokyo metropolitan area — until March 22.

Osaka Gov. Hirofumi Yoshimura speaks to reporters in Osaka Prefecture on Wednesday. | KYODO
Osaka Gov. Hirofumi Yoshimura speaks to reporters in Osaka Prefecture on Wednesday. | KYODO

The natural assumption is that, like Osaka, the capital region — Japan’s most populated area — is bound for a delayed resurgence.

It may have already started.

Nationwide cases have been steady or climbing since early March, but the increase has intensified in recent weeks.

While the latest outbreak is still in its early stages, there are several factors that differentiate the fourth wave from past ones, both in nature and size.

Regional outbreaks of varying severity, compounded by a deep fatigue felt by the millions eager to enjoy the warmer weather and a growing number of cases linked to more contagious variants of the virus, are contributing to an altogether different kind of domestic surge that experts fear may be impervious to past countermeasures.

“The resurgence is disjointed across various parts of the country; coronavirus variants continue to spread at a faster rate and people are starting to relax due to virus fatigue,” said Koji Wada, a professor in public health at the International University of Health and Welfare and a member of the government’s expert panel on the virus. “We’re seeing a new kind of outbreak.”

Over the past 15 months, Japan has experienced three waves of COVID-19, each bigger than the last.

While older people accounted for the majority of those infected during the first wave, which peaked in April, the second wave in July consisted mostly of young people and cluster infections. The third wave, which topped out in early January, featured clusters occurring more broadly across different kinds of places — from office buildings and restaurants to homes and apartment buildings — which made it difficult for officials to trace infection routes.

Kazuyuki Aihara, a professor at the University of Tokyo’s International Research Center for Neurointelligence, believes a rebound in foot traffic during the late stages of the state of emergency is to blame for the latest resurgence.

Aihara is part of a team of researchers who recently announced the development of an early warning system for future outbreaks based on patient data, analysis of the mass movement of people in public places and transportation hubs, as well as the use of biomarkers — an indicator that health professionals can use to measure the presence or severity of an infectious disease.

People walk past cherry blossom trees in bloom along the Meguro River in Tokyo on Saturday. | KYODO
People walk past cherry blossom trees in bloom along the Meguro River in Tokyo on Saturday. | KYODO

The team’s research was used to retroactively predict the peaks of Japan’s first, second and third wave.

“People are going to start going outside, seeing friends and slowly but surely returning to normal life,” Aihara explained.

Aihara has carried doubts about the government’s capacity to trace infections ever since he himself had a close contact last year, after a colleague became infected. He never received any calls from public officials, and nor was he told to isolate himself or seek a virus test, though he did both voluntarily.

“It’s crucial that efforts to retrace infections and chase down clusters are improved dramatically, or else the virus will spread unchecked,” he said. “Reducing the flow of people might be the only way to prevent a massive outbreak.”

Researchers from Tsukuba University believe that even if the vaccination schedule in Japan is sped up, the impact on the ongoing wave would be limited.

According to their research, the outbreak in Tokyo could peak in May at 1,850 cases a day if the city doesn’t begin inoculating residents by then. Even if it does, and more than 35,000 residents are vaccinated daily, the report warned that the capital could still see more than 1,650 cases every day.

Perhaps the most obvious concern is the size and length of the fourth wave. Several signs indicate the outbreak will be significant, especially since new cases were plateauing at a high level before it began.

During the second wave, new cases peaked at 1,605 on Aug. 7. In comparison, on Tuesday nationwide cases topped 2,000, sparking concerns that new cases could surpass the third wave before older people are slated to start receiving vaccinations in April.

In a time of both misinformation and too much information, quality journalism is more crucial than ever.
By subscribing, you can help us get the story right.