96th Meeting of the COVID-19 Advisory Board of the Ministry of Health, Labour and Welfare (August 24, 2022) Material 1

Evaluation of the latest infectious status, etc.

Overview of the infection status

• The number of new cases of infection nationwide (based on the reporting dates) is approximately 1,250 per 100,000 population for the latest week, and the ratio to the previous week is 1.19, which is an increase from last week's downward trend. The highest number ever as been surpassed, as the highest level of infection continues. Increase was seen in most regions, partly due to the influence of socio-economic activities such as Obon and summer vacation.
• As the number of new cases of infection start to increase, the number of patients receiving treatment is also starting to increase. In addition, the use rate of beds is increasing or remains high nationwide. As for the medical care provision system, many cases of difficult emergency transportation and absences of healthcare professionals from work have placed a significant burden not only on treatment for COVID-19, but also on the medical care provision system, including general medical care. There are concerns that the situation will deteriorate further.
  In addition, the numbers of severe cases and deaths are on the rise, and there is particular concern that the number of deaths may further increase to exceed the previous record-high.

  Effective reproduction number: On a national basis, the most recent number is 0.96 (as of August 7), while the figure stands at 0.92 in the Tokyo metropolitan area and 0.94 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 the reporting dates.

1. Hokkaido

   The number of new cases of infection was approximately 933 (approximately 957 in Sapporo City), with a ratio to the previous week of 1.07. The infected individuals are mainly in their 30s or younger. The use rate of beds is approximately 40%.

2. North Kanto

   In Ibaraki, Tochigi, and Gunma, the numbers of new cases of infection were roughly 940, 889, and 900, with ratios to the previous week of 1.31, 1.29 and 1.16, respectively. In Ibaraki, Tochigi, and Gunma, they were mainly in their 30s or younger. The use rates of beds are slightly more than 60% in Ibaraki, slightly less than 70% in Tochigi, and slightly less than 60% in Gunma.

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

   The number of new cases of infection in Tokyo was approximately 1,221, with a ratio to the previous week of 0.96. 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 about 60%. In Saitama, Chiba, and Kanagawa, the numbers of new cases of infection were approximately 946, 764, and 756, with ratios to the previous week of 1.04, 1.06, and 0.94, respectively. The use rate of beds is slightly more than 60% in Saitama and Chiba and slightly more than 70% in Kanagawa.

4. Chukyo/Tokai

   The number of new cases of infection in Aichi was approximately 1,476, with a ratio to the previous week of 1.34. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 70%. In Gifu, Shizuoka, and Mie, the numbers of new cases of infection were roughly 1,398, 1,165, and 1,449, with ratios to the previous week of 1.31, 1.27, and 1.51, respectively. The use rates of beds are slightly less than 60% in Gifu, approximately 70% in Shizuoka, and slightly more than 50% in Mie.

5. Kansai area

   The number of new cases of infection in Osaka was approximately 1,601, with a ratio to the previous week of 1.22. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly less than 70%, while the use rate of beds for severe cases is approximately 50%. In Shiga, Kyoto, Hyogo, Nara, and Wakayama, the numbers of new cases of infection were roughly 1,267, 1,240, 1,378, 1,378, and 1,458, with ratios to the previous week of 1.12, 1.04, 1.13, 1.26, and 1.20, respectively. The use rates of beds are approximately 70% in Shiga, and slightly more than 60% in Kyoto, Hyogo, Nara, and Wakayama.

6. Kyushu

   The number of new cases of infection in Fukuoka was approximately 1,714, with a ratio to the previous week of 1.24. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 70%. In Saga, Nagasaki, Kumamoto, Oita, Miyazaki, and Kagoshima, the numbers of new cases of infection were approximately 1,956, 1,890, 1,697, 1,536, 1,908, and 1,947, with ratios to the previous week of 1.45, 1.33, 1.38, 1.26, 1.20, and 1.27, respectively. The use rates of beds are slightly more than 50% in Saga, Nagasaki, and Miyazaki, slightly more than 60% in Kumamoto and Kagoshima, and slightly less than 60% in Oita.

7. Okinawa

   The number of new cases of infection was approximately 1,758, with a ratio to the previous week of 0.99. 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 patients is slightly more than 30%.

8. Areas other than the above

   The ratios to the previous week in Akita, Yamagata, Fukushima, Toyama, Shimane, Tokushima, Ehime, and Kochi are 1.61, 1.46, 1.45, 1.56, 1.53, 1.79, 1.43, and 1.41, respectively. The use rates of beds are slightly more than 80% in Aomori, slightly more than 60% in Niigata and Okayama, slightly less than 70% in Nagano and Ehime, and slightly more than 70% in Hiroshima.

Infection status and future outlook

Infection status

• The number of new cases of infection increased in most regions, partly due to the increase in socio-economic activities such as Obon and summer vacation. In many regions and nationwide, the highest infection levels continue, surpassing all-time highs. In addition, there are some regions where the number once tended to decrease or remained high, in which rapid increase continues. On the other hand, in Tokyo, Kanagawa, and Okinawa, a decreasing trend can also be seen. In addition, the number of “patients receiving treatment within facilities” has actually been increasing due to a rapid increase in mass infections at facilities for elderly people and shortages of beds. In addition, the rapid increase in cases of infection and close contacts nationwide is still affecting not only medical institutions and welfare facilities, but also social activities as a whole.
• The number of new cases of infection in each age group started to increase nationwide, except among those under the age of 10, with a particularly large increase among those in their 20s. On the other hand, as the trend was before, increases in the number of severe cases and deaths tend to lag behind the rapid increase in the number of new infections. The number of deaths in particular continue to rapidly increase, and there is concern that there will be a further increase in the number of deaths in the future that will exceed the previous record-high number.
• Regarding the place of contracting new infections, the rate of infections that develop at home is still showing an increasing trend, while at schools the trend is changing from decrease to increase. In addition, the percentage of people who contracted the infection at the office (workplace) has increased among people in their 20s to 60s. (It must be kept in mind that active epidemiological surveillance is focused on large cities, and that infection routes are not fully understood).

Future outlook and factors that increase and suppress infection

• Regarding future infection status, the number of new infections may continue to increase or remain high in many regions, based on the epi curve of the date of onset and short-term forecast in large cities. There is also concern about the effects of the reopening of schools after the summer vacation. The number of infected people is unlikely to decrease soon, and the severe situation in the medical care system is expected to continue.
• The main factors affecting the number of infected people include the following.

1. [Vaccination and immunity from infection]

   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. On the other hand, those in their 60s or older are less likely to acquire immunity by infection than those in their 20s to 40s. It is also pointed out that immunity is attenuated, and there is concern that the infection will spread further among elderly people in the future.

2. [Contact patterns]

   The nighttime population curve generally remains flat, and in many areas such as Tokyo and Osaka, it tends to decrease.

3. [Epidemic strain]

   After the prevalence of the BA.2 lineage, it has almost been replaced by the BA.5 lineage, which has become mainstream. The BA.5 lineage is thought to cause an increase the number of infected persons more easily, and there is concern about immune escape, which may be a factor to increase the number of infected persons.

4. [Climatic factors]

   Although it was late August, the weather was still hot, and ventilation may be difficult because air conditioning is prioritized.

Status of the medical care provision system

• Nationwide, the burden on the outpatient examination system is increasing, and the use rate of beds has increased or remains high nationwide, exceeding 50% in most regions. The use rate of beds for severe patients now exceeds 50% in Tokyo and Osaka. In addition, the numbers of home care recipients and medical treatment adjustments remain high in many regions or continue to increase.
• Sufficient manpower cannot be secured yet due to an increase in infections among healthcare professionals nationwide, including Okinawa. The burden on the medical care provision systems has persisted and includes general medical services. In the field of nursing care too, the difficult situation continues due to the increasing numbers of patients being treated in facilities and infection among workers.
• The positive rate of the test remains high, complicating assessment. There is also concern whether the test is appropriately performed on those who need it, such as symptomatic people.
• Although the number of cases of difficulty in emergency transport has decreased nationwide, such cases have increased in some regions and caution should be paid to them. In addition, careful attention should be paid to the increase in cases of ambulance transportation due to the effects of the continuing hot weather.

Measures to be taken

Basic concepts

• In the midst of the spread of infection, it is necessary to reduce, as much as possible the chances of contacts that 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. Furthermore, further efforts should be made to reinforce the medical care provision system, and reduce the burdens on medical institutions and public health centers.

1. 1. Further promotion of vaccinations
   • In a case-control study investigating the efficacy of the SAR-CoV-2 vaccine in Japan, the prophylactic effect against the disease at 5 months after the second vaccination was low compared to unvaccinated cases in the epidemic period of BA.5. On the other hand, 3 doses of vaccination (booster) were shown to possibly increase the prophylactic effect against the disease to a moderate to high degree. It was preliminarily reported that the relative efficacy rate of 3 doses of vaccination compared with 2 doses can be expected to a certain extent.
   • Regarding the booster vaccination with "vaccine for the Omicron variant," it will be prepared for use after the middle of October this year, targeting those who have completed the initial vaccination.
   • For the fourth vaccination, it is necessary to continue efforts to provide earlier vaccination for eligible persons (elderly people aged 60 years and older, and those aged less than 60 years at risk for severe illness, etc.) for prophylaxis against exacerbation. Considering the ongoing spread of infection, workers at medical institutions, facilities for elderly people, etc. where many individuals who are at high risk of becoming severely ill gather, have also been included in those who are eligible for vaccination.
   • Vaccination with recombinant protein may be selected for up to the third vaccination. It has been confirmed that a third vaccination restores the attenuation over time, of both the preventive effect against the Omicron variant and that against aggravation conferred by the first vaccination. Considering the current infection status, it is necessary to promote consideration of the first and third vaccinations at the earliest possible time.
   • Regarding vaccination of children (5-11 years old), the Immunization and Vaccine Section Meeting considered that it was appropriate to impose an obligation to make efforts to vaccinate children, as a certain level of knowledge has been acquired during the spread of the Omicron variant.
2. 2. Use of tests
   • 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.
   • Frequent tests (about 2 or 3 times a week for facility workers) are required for workers at facilities for elderly people.
   • Depending on the circumstances in the area, testing at appropriate occasions is recommended for users of facilities for elderly people.
   • 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 children’s health, and test those with any symptoms.
   • Preliminary testing is further recommended when having a meal with a large number of people or when interacting with elderly people.
   • Establishment of a self-testing system for fever outpatients should be further promoted, 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 at a health follow-up center, etc.
   • In order to promote these 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.
   • It is necessary to promote the utilization of medical antigen qualitative test kits as OTC.
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.
   • In addition to facilitating the use of available hospital beds and developing temporary medical facilities to supplement hospital beds, making efforts to avoid a shortage of hospital beds and emergency medical care, such as utilization of lodging facilities and resting beds
   • Making appropriate adjustments so that patients requiring inpatient treatment can be hospitalized preferentially, performing frequent tests at facilities for elderly people, etc., and further strengthening medical support
   • Securing and expanding logistical support hospitals, and improving the hospital turnover rate, such as by dissemination of the standard for early discharge of 4 days, as a rule
   • Promotion of effective and less burdensome measures against infection, such as flexible and efficient use of hospital beds through zoning of each hospital room
   • Establishment of a self-testing system for fever outpatients should be further promoted, 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 at a health follow-up center, etc.
   • 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
   • Local residents should be informed that they should refrain from visiting an emergency outpatient unit only to receive a precautionary examination without symptoms, according to the actual situation in the region. In addition, in order to respond to concerns and questions at the time of worsening physical conditions, the consultation service by healthcare professionals via telephone should be thoroughly publicized, and this service should also be strengthened.
   • A system of appropriate and early administration of therapeutic drugs should be established and strengthened, such as publication of the registration status of therapeutic drugs in medical care/testing institutions.
   • Response to ambulance transport difficulties In addition to confirming the acceptance system for patients other than those with COVID-19, spreading awareness of heat stroke prevention and warning of increased emergency transportation due to heat stroke.
   • 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.
   • Inspecting and securing oxygen administration systems for patients who temporarily need oxygen administration, such as securing oxygen concentrators, in view of the increase in the numbers of home care recipients and medical treatment adjustments, and medical care in facilities for elderly people.
5. 5. Surveillance
   • Deterioration of the accuracy of current surveillance is a concern due to prioritization of notification items, delays in testing and diagnosis/reporting due to the spread of infection, and changes in healthcare-seeking behavior. It is necessary to promptly promote consideration of effective and appropriate surveillance to grasp the epidemic status. It is also 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.
   • Eating and drinking should be done with as few people as possible, and masks should be worn except while eating and drinking.
   • Continue proper wearing of nonwoven masks, hand hygiene, thorough ventilation, etc.
   • People with symptoms such as sore throat, cough, and fever should refrain from going out.
   • Avoid situations with a high risk of infection, such as the three Cs, congestion, or loud voices.
   • Refer to guidelines for hospital visits and use of an ambulance.
   • To reduce the chances of contact as far as possible, it is necessary for measures at the workplace, such as again promoting the use of telework.
   • 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, and information on how these vaccine effects are attenuated after a third vaccination has become available. Regarding the fourth vaccination, it has been reported that while the preventive effect against aggravation was not reduced for 6 weeks, the preventive effect against infection lasted only for a short time.

6. [Sublineages of the Omicron variant]

   Worldwide, the proportion of the BA.5 lineage is increasing while the number of positive cases increases, suggesting that this lineage is superior to the BA.2 lineage in terms of causing an increase in the number of infected people, but recently the number of positive cases has decreased. 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 severity of BA.5 lineage shows both increased and unchanged data compared to the existing Omicron variants, and continued information collection is needed. In addition, 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 the previous dominant variant was replaced with this lineage.

   In addition, the BA.2.75 lineage, which has been reported mainly in India since June, has been detected in Japan. However, no clear findings have been obtained overseas regarding its infectivity or 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)