On March 15, 2022, 2,578 cases of coronavirus disease (COVID-19) were confirmed in Tokyo Prefecture. The number peaked at around 16.9 thousand on January 31, 2022. Following the accelerated development of cases in the prefecture, the Tokyo prefectural government rose the alert status of the infection level to the highest out of four levels.

Government measures Since the outbreak of the disease in the nation in January 2020, the Japanese government has announced the state of emergency four times for respective prefectures. Tokyo Prefecture was one of the prefectures that were under the state of emergency all four times. To ease the strain on medical facilities, Tokyo prefectural government added about 1,000 beds for COVID-19 patients in private facilities such as sports centers. As of March 2022, over 7,200 beds were designated for patients with the disease in the prefecture.

Tokyo Olympics and Paralympics As a direct impact of COVID-19, the Tokyo 2020 Summer Olympic and Paralympic Games were postponed to 2021. Consequently, the games took place from July to September 2021, one year after the original plan. The games were held without any overseas audience, and initially anticipated economic growth from inbound tourism in the nation did not materialize. 

For further information about the coronavirus (COVID-19) pandemic, please visit our dedicated facts and figure page.

As of September 14, 2022, a cumulative total of approximately 3.1 million people in Tokyo Prefecture tested positive for the coronavirus (COVID-19). Among them, close to three thousand patients were still hospitalized, roughly three million patients were discharged already, and around six thousand patients passed away. Tokyo recorded an accelerated development of new cases per day again from January 2022 onwards.

For further information about the coronavirus (COVID-19) pandemic, please visit our dedicated facts and figure page.

On July 27, 2021, there were ***** positive cases of coronavirus (COVID-19) reported in the near vicinity of the Olympic Summer Games in Tokyo in 2021. Between July 1 and July 27, there have been a total of *** positive cases, of which ** were attributed to athletes.

As of March 17, 2022, the highest number of approximately 1.2 million patients with coronavirus (COVID-19) were confirmed in Tokyo Prefecture in Japan, followed by Osaka Prefecture with about 747.9 thousand people. On that day, all prefectures out of 47 reported new infection cases.

 Tokyo and Kanagawa  The first coronavirus case in Japan was confirmed on January 16, 2020, in Kanagawa prefecture. Part of the Greater Tokyo Area, Kanagawa is the country’s second-most populous prefecture with more than nine million inhabitants. A few days after the first case in Kanagawa, Japan’s second case was reported in Tokyo. Kanagawa and Tokyo, along with Osaka, and four other prefectures, were the first to be placed under a state of emergency by then prime minister Shinzo Abe in April 2020. From the outbreak of COVID-19 until March 2022, the state of emergency was announced four times for Tokyo and three times for Kanagawa Prefecture.

 Osaka Osaka prefecture reported its first case of COVID-19 on January 29, 2020. The prefecture is the center of Japan’s second-most populated urban region, the Keihanshin metropolitan area, which includes Kyoto and Hyogo prefectures. The virus continued to spread in Osaka with the acceleration of new infection cases per day recorded in January, April to May, July to September in 2021, and January and onwards in 2022.

For further information about the coronavirus (COVID-19) pandemic, please visit our dedicated facts and figure page. 

Time series data of the daily reported number of new positive cases of COVID-19 for the entire country of Japan from 16 January 2020 to 21 February 2023.

(a) Phase I (pre-Tokyo Olympic Games, 11 February 2020–22 July 2021). (b) Phase II (post- Tokyo Olympic Games, 23 July 2021–21 February 2023).

There has been a decreasing trend in new severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) cases and fatalities worldwide. The virus has been evolving, indicating the potential emergence of new variants and uncertainties. These challenges necessitate continued efforts in disease control and mitigation strategies. We investigated a small cluster of SARS-CoV-2 Omicron variant infections containing a common set of genomic mutations, which provided a valuable model for investigating the transmission mechanism of genetic alterations. We conducted a study at a medical center in Japan during the Omicron surge (sub-lineage BA.5), sequencing the entire SARS-CoV-2 genomes from infected individuals and evaluating the phylogenetic tree and haplotype network among the variants. We compared the mutations present in each strain within the BA.5 strain, TKYnat2317, which was first identified in Tokyo, Japan. From June 29th to July 4th 2022, nine healthcare workers (HCWs) tested positive for SARS-CoV-2 by real-time PCR. During the same period, five patients also tested positive by real-time PCR. Whole genome sequencing revealed that the infected patients belonged to either the isolated BA.2 or BA.5 sub-lineage, while the healthcare worker infections were classified as BF.5. The phylogenetic tree and haplotype network clearly showed the specificity and similarity of the HCW cluster. We identified 12 common mutations in the cluster, including I110V in nonstructural protein 4 (nsp4), A1020S in the Spike protein, and H47Y in ORF7a, compared to the BA.5 reference. Additionally, one case had the extra nucleotide-deletion mutation I27* in ORF10, and low frequencies of genetic alterations were also found in certain instances. The results of genome sequencing showed that the nine HCWs shared a set of genetic mutations, indicating transmission within the cluster. Minor mutations observed in five HCW individuals suggested the emergence of new virus variants. Five amino acid substitutions occurred in nsp3, which could potentially affect virus replication or immune escape. Intra-host evolution also generated additional mutations. The cluster exhibited a mild disease course, with individuals in this case, recovering without requiring any medical treatments. Further investigation is needed to understand the relationship between the genetic evolution of the virus and the symptoms.

Estimation results for detailed periods.

Estimation results for the weekend afternoon.

In 2021, the three Bar Associations of Tokyo handled about 15 thousand new domestic court cases in total, making it the region in Japan with the highest number of such cases administered at a family court. High case numbers correlated with regions that are densely populated.

Additional file 1.

BackgroundPandemic influenza A(H1N1) virus infection quickly circulated worldwide in 2009. In Japan, the first case was reported in May 2009, one month after its outbreak in Mexico. Thereafter, A(H1N1) infection spread widely throughout the country. It is of great importance to profile and understand the situation regarding viral mutations and their circulation in Japan to accumulate a knowledge base and to prepare clinical response platforms before a second pandemic (pdm) wave emerges. MethodologyA total of 253 swab samples were collected from patients with influenza-like illness in the Osaka, Tokyo, and Chiba areas both in May 2009 and between October 2009 and January 2010. We analyzed partial sequences of the hemagglutinin (HA) and neuraminidase (NA) genes of the 2009 pdm influenza virus in the collected clinical samples. By phylogenetic analysis, we identified major variants of the 2009 pdm influenza virus and critical mutations associated with severe cases, including drug-resistance mutations. Results and ConclusionsOur sequence analysis has revealed that both HA-S220T and NA-N248D are major non-synonymous mutations that clearly discriminate the 2009 pdm influenza viruses identified in the very early phase (May 2009) from those found in the peak phase (October 2009 to January 2010) in Japan. By phylogenetic analysis, we found 14 micro-clades within the viruses collected during the peak phase. Among them, 12 were new micro-clades, while two were previously reported. Oseltamivir resistance-related mutations, i.e., NA-H275Y and NA-N295S, were also detected in sporadic cases in Osaka and Tokyo.

In 2021, the three Bar Associations of Tokyo handled about **** thousand new civil court cases in total, making it the region in Japan with the highest number of such cases administered at a regional court. High case numbers correlated with regions that are densely populated.

The police in Japan's Kanto region recorded 280 homicide cases in 2024. The Kanto region was followed by the the Kinki region, with more than 240 recognized murder cases. That year, the total number of murder cases recorded across Japan amounted to 970.

The police in Japan recorded *** murder cases in 2024, a slight ******** from the previous year. A regional breakdown of murder cases showed that the majority of cases in 2024 occurred in Japan's ***** region.

A total of 712 people were infected with COVID-19 on the Diamond Princess cruise ship – 567 passengers and 145 crew members. The cruise ship, which had more than 3,500 people on board, was quarantined for around two weeks. All passengers and crew members had finally disembarked the ship by March 1, 2020.

What happened on the cruise ship? The Diamond Princess cruise ship was on a 14-day round trip that departed from Yokohama, Japan, on January 20, 2020. The turnaround of passengers and crew was delayed upon the ship’s arrival back in Yokohama because a guest tested positive for COVID-19 after disembarking in Hong Kong. Screening for the virus took place on board the ship, and as the number of positive cases increased, it was confirmed that the ship would remain quarantined until February 19, 2020. Once the quarantine period was over, people who were cleared of the illness were free to leave the ship. All of the 2,666 guests aboard the Diamond Princess had disembarked by February 27, 2020, and the final group of crew members left the ship a few days later.

The coronavirus outbreak in Japan The Diamond Princess cruise ship was carrying passengers from around the world, but approximately half of the guests were from Japan. The country tackled the early outbreak of COVID-19, and Prime Minister Shinzo Abe lifted a month-long state of emergency in late May. However, an upswing in the number of coronavirus cases has highlighted the complexity of easing lockdown measures while the virus is still a threat. Japan is divided into 47 prefectures, and Tokyo has been the most severely affected.