93rd Meeting of the COVID-19 Advisory Board of the Ministry of Health, Labour and Welfare (August 3, 2022) Material 1

Overview of infection status

Overview of infection status

• Nationwide, the number of new cases of infection (by date of report) was about 1,137 per 100,000 in the last week, with a ratio to last week of 1.16, and while the rate of increase has decreased, the number of infections continues to increase. It is again the highest level of infection ever in Japan.
• As the number of new cases of infection increases, the number of patients receiving medical treatment continues to increase, and the use rate of beds continues to rise almost nationwide, and putting a heavy burden on the medical care provision system. In addition, the numbers of severe cases and deaths continue to increase, and attention should be paid to future trends.

  Effective reproduction number: On a national basis, the most recent number is above 1 (1.17 as of July 17), while the figure stands at 1.16 in the Tokyo metropolitan area and 1.19 in the Kansai area.

Local trends

* The value for new cases of infection is the number of persons per 100,000 among the total number for the latest week, based on reporting dates.

1. Hokkaido

   The number of new cases of infection was approximately 753 (about 920 in Sapporo City), with a ratio to the previous week of 1.52. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly less than 30%.

2. North Kanto

   In Ibaraki, Tochigi, and Gunma, the numbers of new cases of infection were about 788, 871, and 814, with ratios to the previous week of 1.49, 1.28, and 1.18, respectively. In Ibaraki, Tochigi, and Gunma, they were mainly in their 30s or younger. The use rates of beds are slightly more than 40% in Ibaraki, slightly more than 50% in Tochigi, and slightly less than 50% in Gunma.

3. Tokyo metropolitan area (Tokyo and 3 neighboring prefectures)

   The number of new cases of infection in Tokyo was approximately 1,595, with a ratio to the previous week of 1.11. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 50%, while the use rate of beds for severe cases is slightly more than 50%. In Saitama, Chiba, and Kanagawa, the numbers of new cases of infection were about 1,125, 1,039, and 1,106, with ratios to the previous week of 1.21, 1.17, and 1.26, respectively. The use rates of beds are slightly more than 60% in Saitama, slightly less than 60% in Chiba, and slightly more than 80% in Kanagawa.

4. Chukyo/Tokai

   The number of new cases of infection in Aichi was approximately 1,240, with a ratio to the previous week of 1.10. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly less than 60%. In Gifu, Shizuoka, and Mie, the numbers of new cases of infection were about 947, 932, and 944, with ratios to the previous week of 1.25, 1.05, and 1.29, respectively. The use rates of beds are slightly less than 50% in Gifu, slightly more than 40% in Mie, and slightly more than 70% in Shizuoka.

5. Kansai area

   The number of new cases of infection in Osaka was approximately 1,576, with a ratio to the previous week of 1.01. The infected individuals are mainly in their 30s or younger. The use rate of beds is approximately 60%, while the use rate of beds for severe cases is slightly less than 40%. In Shiga, Kyoto, Hyogo, Nara, and Wakayama, the numbers of new cases of infection were about 1,178, 1,334, 1,238, 1,020, and 944, with ratios to the previous week of 1.64, 1.29, 1.17, 1.24, and 1.22, respectively. The use rates of beds are slightly more than 60% in Shiga, slightly less than 50% in Kyoto, approximately 60% in Hyogo, slightly less than 60% in Nara, and slightly more than 70% in Wakayama.

6. Kyushu

   The number of new cases of infection in Fukuoka was approximately 1,623, with a ratio to the previous week of 1.10. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly less than 80%. In Saga, Nagasaki, Kumamoto, Oita, Miyazaki, and Kagoshima, the numbers of new cases of infection were about 1,292, 1,053, 1,464, 1,099, 1,351, and 1,367, with ratios to the previous week of 1.05, 1.26, 1.00, 1.04, 1.23, and 1.21, respectively. The use rates of beds are slightly more than 50% in Saga and Nagasaki, slightly more than 60% in Kumamoto, approximately 50% in Oita, slightly more than 40% in Miyazaki, and slightly less than 80% in Kagoshima.

7. Okinawa

   The number of new cases of infection was the highest nationwide at approximately 2,353, with a ratio of this week to last week of 1.04. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 70%, while the use rate of beds for severe cases is slightly more than 40%.

8. Areas other than the above

   Aomori, Niigata, Fukui, Shimane, Okayama, and Hiroshima had ratios to the previous week of 0.97, 1.54, 1.61, 0.81, 1.39, and 1.35, respectively. The number of new cases of infection was approximately 785 in Shimane. The use rates of beds are slightly more than 50% in Aomori and Kochi, slightly less than 60% in Niigata, and slightly more than 60% in Hiroshima.

Infection status and future outlook

Infection status

• The number of new cases has again hit a record high nationwide, and all prefectures have greatly exceeded the previous spread of infection as the spread of infection continues. The infection level in Okinawa continues to be higher than in other regions, while the use rate of beds is also severe. In addition, the rapid increase in cases of infection and close contacts nationwide is affecting not only medical institutions and welfare facilities, but also social activities as a whole.
• The number of new infections nationwide by age group started to decrease among teenagers during the summer vacation, but it continues to increase in most age groups, including the elderly, who are at high risk of aggravation. In the past, increase in the number of severe cases and deaths has tended to lag behind a rapid increase in the number of new infections, and the numbers of severe cases and deaths have already started to increase, raising concerns about future trends.
• Regarding the future infection status, according to the epi curve of onset dates and the short-term forecasts for large cities, some regions are thought to be passed the peak, and in some areas the number of new infections has actually decreased, although new infections are still rising in most regions. In addition, there are concerns about the increase in chances of contact due to summer vacation and the impact of people’s movements during Obon, and therefore it is necessary to pay attention with utmost caution, including the effects on the medical care provision system.
• Factors in the continued increase in the number of infected individuals include (1) the gradual diminishing of the immunity acquired by the third vaccination and infection, (2) the increased contact that is expected due to the influence of summer vacation and Obon, etc., and (3) the presumed replacement of the Omicron variant by lineages such as BA.5.
• Regarding the places of new infections, home is showing an increasing trend, with a decreasing trend at schools, due to the impact of summer vacation. In addition, the percentage of offices (workplaces) is increasing among people in their 20s to 60s (it must be kept in mind active epidemiological surveillance is focused on large cities, and that infection routes are not fully understood).

Factors that increase and suppress infection

1. It is thought that infection status is affected by the following changes in factors that increase and suppress infection.

1. [Vaccination]

   It has become clear that as a certain period elapses after the third vaccination, the infection prevention effect is attenuated compared to the aggravation prevention effect. In addition, the immunity acquired from previous infections is expected to similarly decline in the future.

2. [Contact patterns]

   Although the nighttime population is overall flat, in metropolitan areas such as Tokyo, Kanagawa, Aichi, and Osaka, there are regions where the number is increasing, including the high-risk late night.

3. [Epidemic strain]

   After the prevalence of BA.2 lineage, it is estimated that the BA.5 lineage will become mainstream and replace it. The BA.5 lineage is thought to increase the number of infected persons more easily, and there is concern about immune escape, which may be a factor in increasing the number of infected persons.

4. [Climatic factors]

   It is a time when indoor activities increase due to rising temperatures, but ventilation may be difficult because air conditioning is prioritized.

Status of medical care provision system

• Nationwide, the burden on the outpatient examination system is increasing, and the use rate of beds continues to increase almost nationwide, mostly exceeding 30% including in large cities, and the number of regions exceeding 50% is also increasing. In addition, the numbers of home care recipients and medical treatment adjustments are increasing in most regions, and are rapidly increasing in some regions.
• Especially in Okinawa, the use rate of beds continues to rise, exceeding 70%, and the situation is severe, and nationwide, the increasing number of infections among healthcare workers is placing a burden on the medical care provision system. In the field of nursing care also, the difficult situation continues due to the increasing numbers of patients being treated in facilities and of infections among workers.
• The positive rate of the test has increased, and there is concern whether the test is being appropriately received by those who need it, such as people with symptoms.
• Regarding cases of difficult ambulance transport, both suspected non-COVID-19 cases and suspected COVID-19 cases continue to increase rapidly in many areas, and although the number of incidents has peaked in some areas, we cannot be optimistic about the cause, as a thorough analysis is needed. In addition, as hot weather continues, careful attention should be paid to the increase in ambulance transportation due to heat stroke.

Measures to be taken

Basic concepts

• In the midst of rapid spread of infection, it is necessary to reduce as much as possible the chances of contacts which risk infection, based on the various knowledge that Japanese society has already learned. Also, in order to maintain socio-economic activities, it is necessary to work on methods for people to avoid infecting and being infected.
• To this end, the national and local governments will remind the public of the need for routine infection control measures and take measures to support the public's efforts to prevent infection. In addition, efforts must be made to reduce the number of infected people so as not to increase the numbers of severe cases and deaths as much as possible, and further efforts should be made to strengthen the medical care provision system.

1. 1. Further promotion of vaccination
   • Since the 4th vaccination has a limited effect in preventing infection, it has been promoted at facilities for the elderly with the aim of preventing aggravation. However, in light of the recent rapid spread of infection, the target has been expanded to include healthcare workers and those working in facilities for the elderly.
   • It is necessary to continue to promote the third vaccination by active publicity for the age groups and regions in which the vaccination rate is low.
2. 2. Use of tests

   1. Based on the recommendations of the 17th meeting of the Novel Coronavirus Subcommittee, the national and local governments are required to secure a system that enables testing, and further utilize testing.

   2. [The Elderly]
      • Frequent tests (about 2 or 3 times a week for facility workers) are required for workers at facilities for the elderly.
      • Depending on the circumstances in the area, testing at appropriate occasions (e.g. Obon, when contact with relatives who have returned home is expected) is recommended for users of facilities for the elderly.
   3. [Children]
      • Depending on the circumstances in the area, if a cluster occurs it is necessary to carry out frequent testing of teachers and staff at nursery schools and kindergartens.
      • At the discretion of local governments and schools, it is necessary to thoroughly observe health, test those with some symptoms, and prevent outbreaks while allowing participation in club activities such as tournaments and school trips.
   4. [Young people]
      • Preliminary testing is further recommended when having a meal with a large number of people or when interacting with the elderly (especially when contacting them during the Obon/summer vacation homecoming).
      • A self-testing system for fever outpatients should be established, in which patients with symptoms can self-test using an antigen qualitative test kit, and if the result is positive, they can promptly undergo health observation.
      • In order to promote the above efforts, it is important for the government to provide a stable supply including distribution, by purchasing antigen qualitative test kits, distributing them to prefectural governments, and providing coordination support.
3. 3. Effective ventilation
   • Based on the recommendations of the 17th meeting of the Novel Coronavirus Subcommittee, it is necessary to publicize and recommend effective ventilation methods in the summer when ventilation becomes insufficient due to the use of air conditioners (how to create airflow considering aerosols, installation of partitions that do not block airflow, etc.).
4. 4. Securing a medical care provision system
   • In preparation for further spread of infection, prefectural governments must take measures to avoid overcrowding of beds and fever outpatient sections with the support of the national government.
   • Immediate responses such as securing beds by phase raising, and development of temporary medical facilities that play the role of supplementing hospital beds　　
   • Appropriate coordination for patients who need inpatient treatment so that they can be hospitalized preferentially
   • Further strengthen medical support for testing and facilities for the elderly, based on an intensive implementation plan at facilities for the elderly
   • Securing and expanding logistical support hospitals, coordinating the transfer of patients who meet the criteria for release of medical care, and improving the hospital turnover rate by informing that the decision on early discharge should be 4 days as a rule
   • Promotion of flexible and efficient use of hospital beds through zoning for each hospital room
   • Establishment of a self-testing system for fever outpatients, in which patients with symptoms can self-test using an antigen qualitative test kit, and if the result is positive, they can promptly undergo health observation.
   • Strengthening of the supply system of the antigen qualitative test kits, and understanding and publicizing the cases of home care without going through a fever outpatient section
   • Establishing and strengthening a system that enables appropriate and early administration of therapeutic drugs
   • Response to the increasing trend of ambulance transport difficulties. In addition to confirming the acceptance system for patients other than COVID-19 patients, spreading awareness of heat stroke prevention and warning of increased emergency transportation due to heat stroke.
   • For those who are recuperating at home or staying overnight, in addition to calling for the use of consultations such as call centers, raise awareness of guidelines for visiting medical institutions and using ambulances
   • Ensuring that workplaces and schools do not require test certificates at the start of medical treatment
   • Further promote the reduction of burdens, such as hospitalization coordination and outsourcing/unification of operations by the hospitalization coordination division, so that public health center operations will not be strained.
5. 5. Surveillance
   • It is necessary to promptly consider effective and appropriate surveillance, in order to properly grasp trends regarding occurrences. In addition, it is necessary to continue monitoring the trends of variants through genomic surveillance.
6. 6. Re-inspection and implementation of basic infection control
   • Re-inspection and implementation of the following basic infection control measures are needed.
   • Continue proper wearing of nonwoven masks, hand hygiene, thorough ventilation, etc.
   • Avoid situations with a high risk of infection, such as the three Cs, congestion, or loud voices.
   • Eating and drinking should be done with as few people as possible, and masks should be worn except while eating and drinking.
   • People with symptoms such as sore throat, cough, and fever should refrain from going out.
   • Refer to guidelines for hospital visits and use of an ambulance.
   • In order to reduce the chances of contact, it is necessary to promote the use of telework again at the workplace.
   • Organizers of events, meetings, and such should fully evaluate the epidemic situation and risk of infection in the area, and consider whether or not to hold the meeting, and if it is held, measures should be taken to minimize the infection risk.

<< Reference: Findings on the characteristics of the Omicron variant and its sublineages >>

1. [Infectivity/transmissibility]

   It has been confirmed that compared to the Delta variant, the generation time has shortened to approximately 2 days (approximately 5 days for Delta). The doubling time and incubation period have also shortened, the risk of re-infection and secondary infection after infection has increased, and the speed of infection spread is very fast. According to the reported data, pre-symptomatic transmission has probably occurred to some extent as with the previous strains.

2. [Place/route of infection]

   In Japan, many cases of infection have occurred through the same opportunities as before (spending time indoors in locations with inadequate ventilation, eating and drinking, etc.), and infection is considered to have occurred via the same routes as before (droplets adhering to mucosa, aerosol inhalation, contact infection, etc.).

3. [Severity]

   It has been suggested that infection with the Omicron variant presents a lower risk of hospitalization or aggravation than the Delta variant. However, analyses to date show that the fatality due to infection with the Omicron variant is higher than that due to seasonal influenza. It is also suggested that the incidence of pneumonia is higher than that of seasonal influenza, but given the limited data, it needs to be investigated by various analyses. The death toll from the previous outbreak compared to last summer's outbreak had a higher proportion of people aged 80 and over. It is reported that there are many cases in which the new coronavirus infection is not the direct cause of death, for example, people who have been in a facility for the elderly before the infection are infected and die due to the worsening of the underlying disease. Attention should also be paid to worsening of the condition of elderly infected people and infected people with an underlying disease, and to the onset of heart failure and aspiration pneumonia.

4. [Duration of viral shedding]

   Viral shedding in individuals infected with the Omicron variant decreases over time. In patients with symptoms, it has been shown that the possibility of viral shedding is low from 10 days after the date of onset, and that no shedding is observed after 8 days from the date of diagnosis in those without symptoms.

5. [Vaccine effect]

   For infection with the Omicron variant, the preventive effects of a first vaccination against infection and disease onset are markedly reduced. Its preventive effect on hospitalization is reported to be maintained at a certain level for the first 6 months, but subsequently decreases to 50% or less. On the other hand, it has been reported overseas that a third vaccination restores the infection-preventing effect, onset-preventing effect, and hospitalization-preventing effect against infection by the Omicron variant, as well as information regarding how these vaccine effects are attenuated after a third vaccination. Regarding the fourth vaccination, while the preventive effect against aggravation was not reduced for 6 weeks, the preventive effect against infection was limited, and it was reported that the effect lasted only for a short time.

6. [Omicron variant sublineages]

   Worldwide, the proportion of the BA.5 lineage is increasing, suggesting that this lineage is superior to the BA.2 lineage in terms of increasing the number of infected people. The number of positive tests is on the rise globally, as replacement by the BA.5 lineage proceeds. The BA.5 lineage has shown a tendency to escape existing immunity compared with the BA.1 and BA.2 lineages, but no clear findings on the infectivity have been shown. The effective reproduction number of the BA.5 lineage calculated based on the data of Tokyo was about 1.27 times that of BA.2. It was also estimated that it was about 1.3 times higher in samples collected from private testing institutions nationwide.

   According to the WHO report, the findings accumulated from multiple countries indicate that there is no increase in the severity of the BA.5 lineage compared to existing Omicron variants. On the other hand, the pathogenicity of the BA.5 lineage is reportedly higher than that of the BA.1 and BA.2 lineages, based on Japanese laboratory data, but it has not been confirmed clinically at this time. Although it is unknown whether it is due to the traits of the BA.5 lineage, it should be noted that the numbers of inpatient cases and severe cases are increasing in countries where the number of infected people is increasing mainly in the BA.5 lineage. According to genomic surveillance in Japan, the detection rate of the BA.5 lineage is increasing, and replacement has presumably progressed.

   In addition, the BA.2.75 lineage, which has been reported mainly in India since June, has been detected in Japan, but no clear findings have been obtained overseas regarding its infectivity and severity compared with other lineages. It is necessary to continue to collect and analyze the situation and findings in other countries regarding these characteristics of the virus, and to continue monitoring by genome surveillance.

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