Current Situation of COVID-19 Infection.

8th meeting of the COVID-19 advisory board of Ministry of Health, Labour and Welfare (September 10, 2020) Document 3.

Latest infection status, etc. (as of September 9, 2020).

Trends in new infections

• Infections by the time of onset appear to have reached a peak at the end of July across the country, and the effective reproduction number in Tokyo, Osaka, Aichi, Fukuoka, Okinawa and other cities is recently below 1 (as of August 22).
• New infections are showing a decrease across the country, possibly owing to active measures in high-risk places such as night clubs and similar entertainment establishments where food and beverages are served, cooperation with a request for self-restraint by prefectural governments, and changes in the behavior of citizens; however, the trend in the number of infections varies between regions.
  ・Cumulative number of infections per 100,000 people for one week (September 1 to 7): 3.00 (3,785↓) nationwide, 7.41 (1,032↓) in Tokyo, 2.45 (185↓) in Aichi, 6.24 (550↓) in Osaka, 4.29 (219↓) in Fukuoka, and 6.95 (101↓) in Okinawa
  ・Rate of cases with unknown infection route (August 22 to 28) 50.8% (0.1%↓ from previous week) nationwide, 59.5% (2.4%↓) in Tokyo

Trends among inpatients (*)

• The number of inpatients shows a decreasing tendency. The ratio of the number of inpatients to the number of available beds (in parenthesis) is similar, but slightly higher in some regions.
  ・Number of inpatients (September 2): 4,993↓ (18.9%) nationwide, 1,418↓ (35.5%) in Tokyo, 289↓ (36.5%) in Aichi, 488↑ (38.1%) in Osaka, 260↓ (53.1%) in Fukuoka, and 256↓ (55.5%) in Okinawa
• The number of patients with severe disease has been increasing from early July, and have turned to decrease from late August onward.
  ・Number of patients with severe disease (September 2): 324↓ (10.0%) nationwide, 101↑ (20.2%) in Tokyo, 16↓ (22.9%) in Aichi, 61↓ (32.4%) in Osaka, 14↓ (23.3%) in Fukuoka, and 20↓ (40.8%) in Okinawa

Test systems

• Although the number of tests has fluctuated, the rate of positive test results to the most recent number of tests is 2.9%, which decreased by 1.1% points from the previous week and remains low compared to that under the state of emergency (8.8% from April 6 to 12).
  ・Number of tests (August 31 to September 6): 136,868↑ nationwide, 37,362↑ in Tokyo, 4,110↓ in Aichi, 12,294↑ in Osaka, 8,702↓ in Fukuoka, and 3,513↑ in Okinawa
  ・Rate of positive test results (August 31 to September 6): 2.9% (1.1% points↓ from the previous week) nationwide, 2.8% (1.0% points↓) in Tokyo, 5.0% (1.5% points↓) in Aichi, 4.5% (1.7% points↓) in Osaka, 2.9% (2.2% points↓) in Fukuoka, and 3.0% (5.8% points↓) in Okinawa

* “Trends in numbers of inpatients” are based on “Surveillance of the Status of Care for Patients with Novel Coronavirus Infection and the Number of Beds” by the Ministry of Health, Labour and Welfare. This surveillance is conducted/published at 0:00 on the day of publication. Concerning the number of patients with severe disease, the criteria for the targets differ from those published on August 14 or earlier. ↑ represents increase from the previous week, and ↓ represents decrease.

Evaluations of Recent Infection Status

Infection status

• Concerning the nationwide spread of infection from late June onward, new infections are decreasing from the peak seen in the first week of August, and this tendency is continuing through the Obon holiday to the present. The epidemic curve based on the date of onset of the country overall is in a downward trend since July 27 to 29 onward. On the other hand, the trend of the number of infections varies between regions, e.g., spread of the infection in Mie and in Miyagi.
  * Number of new infections per week: 2,983 for July 11 to 17, 4,703 for July 18 to 24, 7,282 for July 25 to 31, 9,454 for August 1 to 7, 8,036 for August 8 to 14, 7,082 for August 15 to 21, 5,560 for August 22 to 28, and 4,323 for August 29 to September 4
• The effective reproduction number in Tokyo, Osaka, Aichi, Fukuoka, and Okinawa was found to be below 1 most recently on August 22. The value is close to 1 in Tokyo and Osaka, and continuous alert is still necessary for the detection of patients and re-spread of the infection. The rate of positive test results decreased by 1.1% points from the previous week to 2.9%.
• These results may be achieved by active measures in high-risk places where spread of the infection may be triggered, such as night clubs and similar entertainment establishments where food and beverages are served, and effective cooperation with the request for self-restraint by prefectural governments, and the effects of changes in the behavior of citizens who watch news reports on the spread of infection.
  * Tokyo: May 29 and June 27 Calling people’s attention to visiting the downtown at night, July 10 Publication of comprehensive measures based on the opinion exchange between the national, Tokyo metropolitan, Shinjuku Ward and Toshima Ward governments and experts, July 22, etc. Calling on people to refrain from going out
  Osaka: July 28 Request for self-restraint when participating in banquets and drinking parties of 5 or more people (August 1 to 31)
  Request for closing or shortening business hours of restaurants (August 1 to 15 for Okinawa, August 3 to 31 for Tokyo [through
  September 15 for the 23 Wards], August 5 to 24 for Aichi, and August 6 to 21 for Osaka)
  　　Restrictions on the number of participants in large-scale events are maintained for the time being from August 1 (July 22)　　
• On the other hand, the proportion of middle-aged and elderly people among people infected with the virus has been on the rise in August; it was fluctuating at higher levels than in June and July, although it is lower than during March to May. Patients with severe disease have also been increasing from early July onward, but turned to decrease from late August.
  *Proportion of people aged 60 years or older among newly infected people: 10% for July 1 to 7, 9% for July 8 to 14, 11% for July 15 to 21, 11% for July 22 to 28, 12% for July 29 to August 4, 18% for August 5 to 11, 22% for August 12 to 18, 22% for August 19 to 25, and 25% for August 26 to September 1.
• Infection frequently occurred in hospitals and facilities for elderly people after the peak of the epidemic infection spread during March to May. Concerning the epidemics from late June onward, “large-scale” infections in hospitals/facilities are decreasing in the metropolitan area etc., due to early detection, prompt measures to prevent the outbreak and spread of the infection. It is important to continuously take actions to prevent infections in hospitals/facilities, including early detection/prompt measures to minimize the number of patients with severe disease and deaths.

Decrease in fatalities (See the following table and explanation)

• Concerning the spread of infection from June onward, the increase in the number of patients with severe disease compared to the increase in people infected with the virus became more gradual than in March and April. The adjusted fatality rate (*) for the most recent month of May and August showed a decreasing tendency in people of all ages and for all age groups.
  * The adjusted fatality rate is the risk of death during follow-up among cases diagnosed according to a certain definition. This is the adjusted 　　　　estimation of cumulative distribution of the number of days from notification to death. Data update may change the estimation.
• Based on the data of approximately 6,100 inpatients registered in the registry of the National Center for Global Health and Medicine (cases registered by September 4), the ratio of deaths after hospitalization to cases of hospitalization (by generation/severity at admission) was lower for patients hospitalized on June 6 or later than for those hospitalized on June 5 or earlier for all generations although the background of patients, such as underlying comorbidities may differ.
• This decrease may be due to such factors as that
  〇The surveillance sensitivity has improved and more infected people can be confirmed (e.g., expanded test systems, active conduct of tests in places with a high risk of infection, and reduction in the number of days to diagnosis)
  〇The proportion of patients among young generations has increased
  〇Relatively healthy elderly people appear to be included (lower ratio of cases of infection in hospitals and facilities than during the spread of infection in March and May)
  〇Measures concerning the standard of care have been promoted
  　It is necessary to continuously conduct analyses according to the infection status trends.

Future actions

• New infections are decreasing; however, they may increase again in the future. Necessary measures should continuously be taken, e.g., basic preventive measures against infection such as avoiding the “3Cs” and environments where loud voices are raised, wearing a mask indoors, keeping a proper physical distance, and thorough ventilation, measures against infections in hospitals/facilities for elderly people, and prompt actions against cluster outbreaks.
• It is especially important to reinforce active measures in high-risk places such as night clubs and similar entertainment establishments where food and beverages are served, where spread of the infection is triggered in Japan.
• On the other hand, spread of infection may be triggered in different places in the future, and it is required to organize a system to take prompt and appropriate actions against large-scale clusters and cluster chains that may be the origin of infection spread by referring to overseas findings. It is also necessary to take note of the possibility of unexpected re-spread in some regions.
• The infection status should continuously be monitored/evaluated, and prompt actions should be taken to drastically expand the test systems, secure medical care provision systems, and organize the system of health centers based on “Future Actions for Novel Coronavirus Infections” (determined by the Novel Coronavirus Infections Control Headquarters on August 28, 2020). Investigation should also promptly be promoted to review the operations of the authorities concerning the recommendations for hospitalization in the Infectious Diseases Control Act in accordance with the discussion in the working group established in this advisory board.

 Comparison of adjusted fatality rate: Estimation as of August 30 and Ratio of deaths after hospitalization to the cases of hospitalization due to novel coronavirus infections (PDF).