国立感染症研究所

29th meeting of the COVID-19 advisory board of Ministry of Health, Labour and Welfare (April 7, 2021).  Material 1

 

Evaluation of the latest infection status, etc.

Infection status

  • The number of new cases of infection nationwide has continued to increase since early March based on the reporting date, and the number in the most recent week is approximately 14 per 100,000 population. With a rapid increase in the Kansai area, the rate of increase is rising from late March. The number of patients with severe symptoms took an upturn in late March with increases in the number of new cases of infection. Attention should be paid to the speed of increase in severe cases.

    The effective reproduction number: exceeded 1 in late February and has recently reached 1.16 (as of March 21). The figure reached above 1 on March 22 in Miyagi, Tokyo and its 3 neighboring prefectures, as well as Aichi and Gifu, Osaka, Hyogo and Kyoto; especially in the latter 3 where it has risen to 1.74.

  • There is still an increasing trend in the number of persons infected with the mutant strains such as N501Y, designated as a variant of concern (VOC), and clusters have continued to occur. In particular, many cases of infection have been reported in Osaka and Hyogo. The proportion of mutant strains (VOC) detected by screening tests, which are just based on mechanical estimate, remains high and the number of persons infected with mutant strains (VOC) is also increasing in the surrounding areas.
[Local trends]

*The value of new cases of infections is the number of people per 100,000 in the total number for the latest week on the basis of reporting dates.

  1. (1) Metropolitan area (Tokyo and its 3 neighboring prefectures) The number of new cases of infection has continued to increase since mid-March to approximately 20 in Tokyo. A sign of increase has been observed in Kanagawa and Saitama from the beginning of April while the figure remains stable in Chiba. The burden on medical care provision systems has been reduced. In Tokyo, the number of inpatients made an upturn in mid-March, the use rate of beds increased, and the cases of hospitalization/medical care being adjusted are increasing.
  2. (2) Kansai area/Chukyo area/Kyushu There have been more reports on mutant strains in the Kansai area. Furthermore, the number of cases of infection has rapidly increased since mid-March in Osaka and Hyogo with an increase in the flow of people, and the figure has also considerably increased since late March in Kyoto, Nara, and Wakayama. Moreover, in Osaka, the infection is spreading in cities other than Osaka City, and the number of new cases of infection is approximately 47. Particularly in Osaka and Hyogo, the overall use rate of beds and use rate of beds by patients in severe conditions are rapidly increasing with the upsurge in number of new cases of infection, putting the medical care provision systems under very severe pressure. In Aichi, the number of cases of infection has increased since late March. The figure remains stable in Fukuoka.
  3. (3) Areas other than those listed above The infection had rapidly spread in Miyagi and Yamagata, however, the number of new cases of infection began to decrease at the end of March to approximately 36 and 15, respectively. Cases are mainly in persons aged under 50; the number of inpatients is increasing in Miyagi. The infection has also rapidly spread since late March in Okinawa. The number of new cases of infection is approximately 46. While the proportion of infected persons in their 20s to 50s is large, the number of inpatients has increased. The number of infections due to clusters, etc. rapidly increased in some other regions. An increasing trend has been observed in Ehime, and then Tokushima and Kagawa in the Shikoku area.

Analysis of infection status

  • There is still concern that the infection may spread further in the Kansai area. The number of cases of infection is increasing not only in Osaka and Hyogo, but also in the surrounding areas. Attention should be paid to the rapid increase in the number of cases of infection with mutant strains in the surrounding areas as well. The flow of people is decreasing in Osaka, however, it will take a certain period of time to see a decrease in the number of new cases of infection. There is also a concern about the continued spread of infection and increase in the number of inpatients. There is a great need to be more vigilant about the situations while monitoring the conditions of medical care provision systems.
  • The number of cases of infection is slightly decreasing in Tokyo and its 3 neighboring prefectures. In Tokyo, the nighttime population rapidly increased after the Declaration of a State of emergency was lifted. The infection has spread in persons in their 20s and 30s despite the recent decrease in figures. Looking at the recent spread of infection in Osaka, Hyogo and Miyagi, etc., the flow of people is increasing after lifting of requests for shortening of business hours in accordance with the measures under the Declaration of a State of Emergency, and the spread of infection has occurred at around 3 weeks after lifting the Declaration. There is concern that the spread of infection may continue or spike in metropolitan areas including Tokyo. The proportion of mutant strains (VOC) detected by screening tests is also increasing. In Miyagi and Yamagata, the flow of people decreased and the number of cases of infection began to decrease after the original measures of the prefectures were implemented. The government of Okinawa started its own measures. Although the increase in the number of cases of infection slowed down, the increasing trend continued, and the infection spread mainly in young people. The progress in these trends should be monitored from now on.
  • The places of clusters are diverse, including medical institutions, welfare facilities, schools, workplaces, restaurants, scenes of eating and drinking, and sports. Clusters have occurred in restaurants and karaoke bars during the day. Such clusters should be carefully monitored.
  • There is concern in some regions that the proportion of mutant strains (VOC) will continue to grow and there will be further rapid spread of infection and high infectivity of these strains compared to the existing ones.

Measures to be taken

  • In Miyagi, Osaka, and Hyogo, which were designated as areas to be subject to the priority measures such as prevention of the spread of infection in view of the rapid spread of infection, necessary measures should be steadily taken including thorough patrols and requests for restaurants including the shortening of business hours to 20:00, which should be implemented in application of this measure, as well as priority testing, securing medical care provision systems, and requesting restaurants to refrain from using karaoke equipment. Particularly in Osaka and Hyogo, reported cases of mutant strains (VOC) increased in many cases of infection reported. The medical care provision systems have already been under severe pressure, and securing beds for patients in severe conditions, which are expected to increase, should be prioritized. The infection is rapidly spreading beyond Osaka City to neighboring Kyoto, Nara, and Wakayama. Prompt and appropriate measures are required to prevent spread of mutant strains associated with movements of people to other regions, including non-essential and non-urgent outings and movements. It is also required to conduct analyses of the causes of the spread of infection and take measures against the spread of infection based on these analyses.
  • In other regions where the number of cases of infection is increasing, it is necessary to promptly make efforts to control the infection in view of the infection status. It is required to take measures such as requests to shorten the business hours of restaurants and patrols, requests asking people to refrain from going out, improvements for systems to conduct tests without delay, and prompt surveys of close contacts and the sources of infection. Based on such measures, it is necessary to secure medical care provision systems and public health systems to respond to further spread of infection, in addition to support by the national government. Immediate action should be taken.
  • For the Tokyo metropolitan area, the number of cases of infection is increasing particularly in Tokyo, and the nighttime population and proportion of mutant strains detected are likely to induce significant concern about the future course of the disease. As with Osaka and Hyogo, the spread of infection may occur after lifting the Declaration of a State of Emergency. It is necessary to promptly organize testing/consultation systems assuming re-spread of infection and medical care provision systems including recuperation at accommodation facilities and at home, as well as sufficient and timely measures responding to the infection status.
  • The number of cases of infection has rapidly increased in areas outside the metropolitan area where no large-scale spread of infection had previously occurred. Assuming that an actual spread of infection will also occur in regions with no previous large-scale spread of infection, it is necessary to check again whether necessary preparations have been made, such as securing consultation/testing systems and beds/accommodation facilities for recuperation, securing systems for arrangements including recuperation at home and systems for support from the entire government agency, as well as collaborative systems between prefectures and cities with health centers in case of a new spread of infection.
  • There is already a new sign of a spread of infection with movements of people associated with the change to a new fiscal year. In order to prevent further spread of infection, it is necessary to ask people to refrain from opportunities of people getting together such as 3Cs (closed spaces, crowded places, and close contact settings), and parties associated with various events for the beginning of new fiscal year. Furthermore, for the prevention of infection, people should be appropriately informed of the risk of infection in situations where the elderly will get together such as daytime karaoke and product sales with customer service, eating and drinking together for a long time during the day, and actual situations of clusters. In addition, it is necessary to urge patients with symptoms to undergo the test followed by rapid conduct of the test.
  • Prompt actions for mutant strains with mutation in N501Y (VOC) are required based on evaluations/analyses of epidemiological information on the regional status of infection, infectivity, and pathogenicity considering the recent increase in the number of cases of infection. Particular discussion should be promptly made about actions in medical care provision systems and public health systems, including allocation of private rooms for patients infected with mutant strains and revision in the discharge criteria.

Figures (Number of new infections reported etc.) (PDF)

Copyright 1998 National Institute of Infectious Diseases, Japan

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