90th Meeting of the COVID-19 Advisory Board of the Ministry of Health, Labour and Welfare (July 13, 2022). Material 1

Evaluation of the latest infection status, etc.

Infection status

• The number of new cases of infection nationwide (by date of report) was about 290 per 100,000 in the last week, rapidly increasing at a ratio of this week to last week of 2.14.
  It is increasing in all prefectures and age groups.
• As the number of new cases of infection increases, the number of patients receiving medical treatment is increasing, and although the use rate of beds is generally low, it is on the rise.
• At present, the numbers of severe cases and deaths remain low.

  Effective reproduction number: On a national basis, the most recent number is above 1 (1.14 as of June 26), while the figure stands at 1.19 in the Tokyo metropolitan area and 1.16 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 111 (about 135 in Sapporo City), with a ratio to the previous week of 1.37. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly less than 10%.

2. North Kanto

   In Ibaraki, Tochigi, and Gunma, the numbers of new cases of infection were about 118, 122, and 160, with ratios to the previous week of 2.05, 2.58, and 2.70, respectively. In Ibaraki and Tochigi, they were mainly in their 30s or younger, and in Gunma, mainly in their 20s or younger. The use rates of beds are slightly more than 10% in Ibaraki and Gunma, and approximately 10% in Tochigi.

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

   The number of new cases of infection in Tokyo was approximately 446, with a ratio to the previous week of 2.37. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 20%, and the use rate of beds for severe cases is slightly more than 30%. In Saitama, Chiba, and Kanagawa, the numbers of new cases of infection were about 232, 246, and 296, with ratios to the previous week of 2.19, 2.33, and 2.41, respectively. The use rates of beds are slightly more than 20% in Saitama, Chiba, and Kanagawa.

4. Chukyo/Tokai

   The number of new cases of infection in Aichi was approximately 294, with a ratio to the previous week of 2.26. The individuals are mainly in their 20s or younger. The use rate of beds is slightly less than 20%. In Gifu, Shizuoka, and Mie, the numbers of new cases of infection were about 235, 212, and 224, with ratios to the previous week of 2.18, 2.65, and 2.07, respectively. The use rates of beds are slightly less than 20% in Gifu and Shizuoka, and approximately 30% in Mie.

5. Kansai area

   The number of new cases of infection in Osaka was approximately 421, with a ratio to the previous week of 2.22. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 20%, and the use rate of beds for severe cases is slightly less than 10%. In Shiga, Kyoto, Hyogo, Nara, and Wakayama, the numbers of new cases of infection were about 243, 284, 276, 250, and 306, with ratios to the previous week of 2.29, 2.27, 2.13, 3.01, and 2.09, respectively. The use rates of beds are approximately 20% in Kyoto, slightly more than 40% in Wakayama and Shiga, slightly less than 30% in Hyogo, and slightly more than 10% in Nara.

6. Kyushu

   The number of new cases of infection in Fukuoka was approximately 406, with a ratio to the previous week of 2.27. The individuals are mainly in their 20s or younger. The use rate of beds is slightly more than 20%. In Saga, Nagasaki, Kumamoto, Oita, Miyazaki, and Kagoshima, the numbers of new cases of infection were about 626, 298, 640, 402, 379, and 409, with ratios to the previous week of 2.00, 1.58, 1.75, 2.24, 2.24, and 1.97, respectively. The use rates of beds are approximately 30% in Saga, slightly more than 20% in Nagasaki, slightly less than 50% in Kumamoto, approximately 30% in Oita, slightly more than 30% in Kagoshima, and approximately 20% in Miyazaki.

7. Okinawa

   The number of new cases of infection was the highest nationwide at approximately 1,118, with a ratio of this week to last week of 1.52. 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 20%.

8. Area other than the above

   In Iwate, Akita, Yamanashi, Nagano, Tottori, and Shimane, the ratio to the previous week was 2.77, 3.57, 2.61, 2.58, 2.18, and 1.80, respectively, and the number of new cases of infection in Shimane was about 776. The use rates of beds are slightly less than 30% in Aomori, slightly more than 20% in Fukushima, and slightly more than 30% in Shimane.

Future outlook and measures to be taken

• Infection status

  • The number of new cases of infection is increasing in all prefectures, and in many areas the increase is large and the infection is spreading rapidly. In addition, Okinawa continues to have a higher level of infection than other areas, and is now the highest level to date.

  • The number of new cases of infection by age group increased in all age groups, and the rate of increase was particularly large among those in their 50s or younger.

  • Regarding the places of infection of new cases, the proportion at schools and at home are increasing (it must be kept in mind active epidemiological surveys are focused on large cities, and that infection routes are not fully understood). In Tokyo, an increase in infections at places of eating, drinking, and work has also been reported.

  • Regarding future infection status, the number of new infections is expected to continue to increase in many regions, based on the epi-curve of the date of onset and short-term forecast in large cities. Since (1) the immunity acquired by the third vaccination and infection is gradually decreasing, (2) an increase in contact is expected due to the influence of three consecutive holidays and summer vacation, and (3) replacement of the Omicron variant by lineages such as BA.5 is proceeding, there is concern that the number of infects will continue to increase rapidly, and it will be necessary to pay close attention to the impact on the medical care provision system.

• 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]

     The third vaccination is proceeding, but it should be noted that as a certain period elapses after the third vaccination, it is expected that the infection prevention effect will be weakened 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 decreasing in some regions, it shows an increasing trend in many areas, mainly in large cites. Since in some areas the number approaches or exceeds the peak at the end of last year, it is necessary to pay attention to the impact on the infection status.

  3. [Epidemic strain]

     After the prevalence of BA.2 lineage, the replacement by BA.5 lineage is progressing. In particular, 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.

• Medical care provision system

  • Nationwide, the use rate of beds is generally low, but as the number of newly infected individuals increases, it has been on an upward trend in some areas, including large cities. Especially in Okinawa, the use rate of beds tends to be higher than in the country as a whole.

  • In cases of difficult emergency transportation, there is an increasing trend nationwide for both suspected non-COVID-19 cases and suspected COVID-19 cases. In addition, careful attention should be paid to the increase in ambulance transportation due to heat stroke.

• Efforts based on the spread of infection with the Omicron variant

  1. [Surveillance, etc.]

     It is necessary to 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. For severe cases, clusters, and other applicable cases, confirmation via PCR testing for mutant strains and a whole-genome analysis is required.

  2. [Efforts by local governments]

     1. The number of new cases of infection is increasing in all prefectures, and local governments need to continue to inspect and strengthen their testing, health, and medical care provision systems.

     • It is necessary to strengthen the system to enable prompt and smooth testing and safe home care that keeps up with the spread of infections in the region, and continue the inspection and strengthening of testing, health, and medical care provision systems that have been developed so far, such as further securing of beds.
     • Recently, effective and less burdensome measures against infection in medical and nursing care settings have been newly seen, and while knowledge about the risk of infection and infection control has accumulated, it is important to consider reasonable measures against infection according to the actual conditions at each facility.
     • When strengthening and thoroughly implementing a medical care support system for the elderly, it is important for medical and nursing care departments to cooperate, and proceed in consultation with local concerned parties so that the system that has been developed thus far is functioning properly.
     • Based on administrative notices such as to prioritize health observation and improve efficiency in processing notices of the occurrence of patients, in order to efficiently carry out public health center operations and maintain the public health center functions required in the region, it is important to secure a system for outsourcing or centralization at the main office.
  3. [Provision of information to unvaccinated individuals, and those receiving the third or fourth vaccination, etc.]
     • It is important for local governments to promote the provision of information on vaccination. The third and fourth vaccinations must also be steadily implemented, along with vaccinations for unvaccinated persons. The main purpose of the third vaccination is prevention of onset and aggravation. As of July 12, the rate of third vaccinations was about 90% for the elderly aged 65 years and older, and about 62% overall. It is necessary to steadily implement a third vaccination in subjects, and to vaccinate as many desiring recipients as possible. A fourth vaccination was started to prevent aggravation in persons aged 60 years and older, persons with underlying diseases at high risk of severe symptoms, and other persons deemed by doctors to be at a high risk of severe symptoms. It also became possible to start administration of a new vaccine for the first to third doses. This vaccine is different from the previous new coronavirus vaccine and can ensure a diversity of vaccines. It is also manufactured in Japan, ensuring the stability of vaccine supply.
     • Vaccination of children from 5 to 11 years old is being implemented as a special temporary vaccination, and it is necessary to promote vaccination, considering that the obligation to make efforts does not apply to these children. In hope of preventing infections in children, it is also important for parents and the adults around them to be vaccinated a third time.
  4. [Quarantine measures]

     It is necessary to verify the step-by-step review of quarantine measures, while taking into account the status of the current epidemic situation overseas and in Japan. In addition, while continuing pre-departure tests and responding to the risk of inflow, whole genome analysis should be continued for those who are positive in the immigration test to monitor strains circulating overseas.

• Strengthening and thorough implementation of infection prevention measures based on the characteristics of the Omicron variant

  1. In situations and places where infection is widespread, it is necessary to strengthen and thoroughly implement infection control measures, based on the characteristics of the Omicron variant.

  2. [Schools, kindergartens, nursery schools, etc.]

     Infection control measures including active promotion of vaccinations for teachers and nursery teachers will be thoroughly implemented, as well as infection control measures for children, while sharing situations where the risk of infection in children and students increases with staff, children, parents, etc. It is also necessary to continue educational activities and social functions as far as possible. It is important to establish an environment where children and workers can take a leave of absence, in the case of any poor health conditions. At the same time, thorough infection control measures are also required at home. Masks are not recommended for children under 2 years of age, and for preschool children over 2 years of age, there are concerns about the risk of heat stroke and the effects of difficulty in seeing facial expressions. Therefore, it is necessary to thoroughly inform nursery schools, etc. that masks are not uniformly required, and that children should not be forced to wear them. Schools must be thoroughly informed that it is not necessary to wear a mask during physical education classes, athletic club activities, or when going to and from school.

  3. [Facilities for the elderly, etc.]

     Thorough measures are needed to control infections in the elderly. Therefore, workers are actively examined. In order to prevent aggravation, the fourth vaccination of residents will proceed. Further, it is important to secure external support systems for infection control and medical care at facilities, and to promptly intervene when infection is confirmed at facilities.

  4. [Workplace, etc.]

     In order to maintain social functions, in addition to reinspection and utilization of business continuity plans, efforts are required to utilize telework and promote the taking of time off. In addition, thorough health management of employees, including the use of apps, and securing an environment where they can take a leave of absence if they are even a little unwell are necessary. In addition, a third vaccination in the workplace should be actively promoted.

• It is essential to widely share the current infection status with citizens and business operators, and cooperate toward preventing the spread of the infection.

  1. The number of new cases of infections is increasing in all prefectures. The number of contacts is expected to increase due to the three consecutive holidays and summer vacation. For this reason, in order to minimize the increase in the number of cases of infection, it is necessary to thoroughly implement basic infection control measures and daily health management, and cooperate in efforts to reduce the risk of infection.

  2. [Vaccination]

     In preparation for the spread of infection, a fourth vaccination is recommended for the elderly and those at risk of severe illness. It is important for people to receive the third vaccination, regardless of type. People with the novel coronavirus disease may experience severe conditions even if they are young, and may also suffer from prolonged symptoms. Accordingly, it is necessary to promote vaccinations not only in the elderly, but also in younger persons, in order to protect their health. It is important to consider vaccination again for people who have not received the first or second vaccination.

  3. [Thorough infection control]

     As basic infection control measures, it is necessary to continue to ensure the proper wearing of nonwoven masks, hand washing, ventilation, etc. The risk of infection becomes highest when the three Cs (crowded places, closed spaces, and close contact) overlap. However, even a single C should be avoided as much as possible.

  4. [When going out]

     Crowded or poorly ventilated places with a large number of people and loud voices, where the risk of infection is high, should be avoided. Activities with other persons should be carried out in a small group of people who usually meet each other. Eating and drinking together should be done in a small group without speaking to the extent possible, and masks should be worn at all times except while eating and drinking. On the other hand, the use of a mask is not necessary outdoors, except when talking at a close distance. Especially in summer, removing the mask outdoors is recommended from the viewpoint of preventing heat stroke.

  5. [Health management]

     It is necessary to refrain from going out if you feel a little unwell, such as a mild fever or fatigue, and to consult with a physician and undergo tests according to local government policy. Particularly, if there is a chance of meeting people at high risk of severe illness, such as the elderly, it is necessary to check the condition before visiting, and also to recommend a preliminary test using an antigen test kit, etc.

<< 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. People aged 80 years and older account for a larger proportion of deaths in this wave of the spread of the infection than during last summer. It has been 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 at 10 days after the date of onset. In patients with no symptoms, it has been shown that viral shedding does not occur 8 days after the date of diagnosis.

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.

6. [Sublineages of the Omicron Variant]

   Worldwide, the proportions of the BA.4 and BA.5 lineage are increasing, suggesting that these lineages are 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.4 and BA.5 lineages proceeds. 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.

   According to the WHO report, the findings accumulated from multiple countries indicate that there is no increase in the severity of the BA.4 and BA.5 lineages 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. 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 BA.4 and BA.5 lineages.

   The BA.4 lineage and BA.5 lineage have both been detected in Japan and in quarantine. According to genomic surveillance, the BA.2 lineage continues to be the mainstream in Japan, but the detection rate of the BA.5 lineage is increasing, and replacement is progressing. It is necessary to continue to collect and analyze the situation and findings in other countries regarding the characteristics of the virus, and to continue monitoring by genome surveillance.

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