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72th meeting of the COVID-19 advisory boardof Ministry of Health, Labour and Welfare (February 16, 2022). Material 1

 

Evaluation of the latest infection statsu, etc.

Infection status

  • The number of new cases of infection nationwide (by date of report) decreased to about 464 per 100,000 in the last week, with the ratio of this week to last week at 0.90. The number of newly infected people by age group has shown a decreasing trend in almost all age groups, and only those in their 80s and older have increased slightly.
  • Among the 36 prefectures that are currently under priority preventative measures, 32 of them show a downward trend in the number of new cases of infection, with a ratio to that for the previous week of less than 1. In other prefectures, the ratio to that for the previous week is also on a downward trend, and the rate of increase continues to slow down. In Hiroshima, where the number of new cases of infection continues to decrease, all age groups are showing a decrease. However, it should be noted that in many areas, the number of patients in their 80s and older continues to increase. Among prefectures where priority measures are not in force, Akita, Yamanashi, Shiga, Tottori, and Ehime have a ratio to that for the previous week of less than 1.
  • Although the number of new infections has been decreasing nationwide, the numbers of patients receiving treatment, severe cases, and deaths continue to increase.

    Effective reproduction number: On a national basis, the most recent number is below 1 (0.98; as of January 31), while the figure stands at 0.99 in the Tokyo metropolitan area and 0.97 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.

< Areas under priority measures >
  1. Hokkaido

    The number of new cases of infection was approximately 419 (about 559 in Sapporo City), with a ratio that for to the previous week of less than 1 (0.91). The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 30%.

  2. Tohoku

    In Aomori, the number of new cases of infection is approximately 213, with a ratio to that for the previous week of less than 1 (0.97). The infected individuals are mainly in their 20s or younger. The use rate of beds is approximately 50%. In Yamagata and Fukushima, the number of new cases of infection has also decreased to approximately 123 and 152, respectively, with a ratio to that for the previous week of less than 1 (0.72 and 0.78). The use rate of beds is slightly more than 40% in Yamagata and about 50% in Fukushima.

  3. North Kanto

    In Gunma, the number of new cases of infection is approximately 272, with a ratio to that for the previous week of less than 1 (0.78). The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 60%, while the use rate of beds for severe cases is slightly more than 20%. In Ibaraki and Tochigi, the number of new cases of infection was approximately 332 and 273, respectively, with a ratio to that for the previous week of less than 1 (0.96 and 0.91). The use rate of beds is slightly less than 40% in Ibaraki and slightly more than 40% in Tochigi.

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

    In Tokyo, the number of new cases of infection is approximately 758, with a ratio to that for the previous week of less than 1 (0.82). The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly less than 60%, while the use rate of beds for severe cases is slightly more than 40%. In Saitama, Chiba, and Kanagawa, the number of new cases of infection was approximately 481, 526 and 574, respectively, with a ratio to that for the previous week of less than 1 (0.87, 0.98 and 0.94). The use rate of beds is slightly less than 60% in Saitama, slightly less than 70% in Chiba, and slightly more than 70% in Kanagawa. The use rate of beds for severe cases is slightly more than 20% in Saitama, approximately 20% in Chiba and slightly more than 40% in Kanagawa.

  5. Chubu/Hokuriku

    In Ishikawa, the number of new cases of infection is approximately 246, with a ratio to that for the previous week of less than 1 (0.83). The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 60%, while the use rate of beds for severe cases is slightly more than 20%. In Niigata and Nagano, the number of new cases of infection was approximately 153 and 176, respectively, with a ratio to that for the previous week of less than 1 (0.98 and 0.91). The use rate of beds is slightly more than 20% in Niigata and slightly more than 40% in Nagano.

  6. Chukyo/Tokai

    In Aichi, the number of new cases of infection has increased continuously to approximately 540, with a ratio to that for the previous week of 1.03. The infected individuals are mainly in their 30s or younger. The use rate of beds is approximately 70%, while the use rate of beds for severe cases is slightly more than 20%. In Gifu, the number of new cases of infection has increased continuously to approximately 318, with a ratio to that for the previous week of 1.05. In Shizuoka and Mie, the number of new cases of infection was approximately 290 and 266, respectively, with a ratio to that for the previous week of less than 1 (0.90 and 0.91). The use rate of beds is slightly less than 60% in Gifu, slightly more than 50% in Mie, and slightly more than 40% in Shizuoka.

  7. Kansai area

    In Osaka the number of new cases of infection was the highest in Japan (approximately 943), but with a ratio to that for the previous week of less than 1 (0.94). The infected individuals are mainly in their 30s or younger. The use rate of beds exceeded 100%, while the use rate of beds for severe cases is slightly more than 50%. In Kyoto, Hyogo, and Wakayama,, the number of new cases of infection is 592, 628, and 343, respectively, with a ratio to that for the previous week of less than 1 (0.86, 0.88, and 0.89). The use rate of beds is approximately 70% in Kyoto, slightly more than 70% in Hyogo, and slightly less than 70% in Wakayama. The use rate of beds for severe cases is slightly more than 60% in Kyoto, slightly more than 30% in Hyogo, and slightly less than 20% in Wakayama.

  8. Chugoku/Shikoku

    In Hiroshima, the number of new cases of infection is approximately 222, with a ratio to that for the previous week of less than 1 (0.83). 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 patients is approximately 30%. In Okayama, Yamaguchi, and Kagawa, the number of new cases of infection has also decreased to approximately 306, 143, and 242, respectively, with a ratio to that for the previous week of less than 1 (0.78, 0.89, and 0.98). In Shimane and Kochi, the number of new cases of infection was approximately 86 and 256, respectively, with a ratio to that for the previous week increasing to 1.12 and 1.14. The use rate of beds is slightly less than 30% in Shimane, slightly more than 50% in Okayama, slightly less than 40% in Yamaguchi, and slightly less than 50% in Kagawa and Kochi. The use rate of beds for severe cases is slightly more than 20% in Okayama and slightly more than 40% in Kochi.

  9. Kyushu

    In Fukuoka, the number of new cases of infection is approximately563, with a ratio to that for the previous week of less than 1 (0.88). The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 80%. In Saga, Nagasaki, Kumamoto, Oita, Miyazaki, and Kagoshima, the number of new cases of infection is 374, 223, 310, 234, 163, and 241, respectively, with a ratio to that for the previous week of less than 1 (0.86, 0.81, 0.90, 0.87, 0.77, and 0.92). The use rate of beds is slightly more than 40% in Saga, Nagasaki and Oita, slightly more than 60% in Kumamoto, approximately 40% in Miyazaki, and slightly more than 50% in Kagoshima. The use rate of beds for severe cases is approximately 20% in Kumamoto.

  10. Okinawa

    The number of new cases of infection is approximately 268, and the ratio to that for the previous week remains less than 1 (0.91). In the Yaeyama and Miyako districts, the increase is continuing. The newly infected individuals are mainly in their 30s or younger. The use rate of beds is about 50%, and the use rate of beds for severe cases is about 50%.

< Areas other that the above >
    1. In Iwate, Miyagi, Toyama, Fukui, Nara, and Tokushima, the number of new cases of infection is approximately 95, 211, 247, 207, 577, and 178, respectively. All of these prefectures show an increase, with a ratio to that for the previous week of more than 1. In Akita, Yamanashi, Shiga, Tottori, and Ehime, the number of new cases of infection is 131, 231, 426, 93, and 112, respectively, with a ratio to that for the previous week of less than 1 (0.99, 0.98, 0.86, 0.76, and 0.84). The use rate of beds is slightly more than 40% in Iwate and Miyagi, slightly more than 30% in Akita and Tokushima, slightly less than 70% in Yamanashi, approximately 30% in Toyama, slightly more than 20% in Fukui and Tottori, slightly more than 70% in Shiga and Nara, and slightly less than 40% in Ehime. The use rate of beds for severe cases is slightly more than 60% in Nara, and approximately 20% in Ehime.

* The bed use rate and bed use rate for severe cases are shown on the website of the Cabinet Secretariat.

Future outlook and measures to be taken

  • The number of newly infected people nationwide has continued to decrease, with the effective reproduction number and the ratio of this week to last week at 1 or less, and the total for the last week turned to a decrease. However, the infection still seems to occur at certain places, such as homes, schools, nursery schools, workplaces, and nursing welfare facilities. In many of areas under priority measures, the number of newly infected people has been decreasing or has stopped rising, but there are signs that the nighttime population will reverse and increase in some areas under priority measures. In addition, it has been pointed out that the published data may deviate from the actual situation due to delays in reporting. It is necessary to pay attention to the possibility that the number will increase again by replacement by the BA.2 lineage in the future, although there are no signs of this yet.
  • The number of people infected with the Delta variant, which has almost been replaced by the Omicron variant and is more likely to become severe, is decreasing, but it is still detected. In Okinawa, where a prevalence of infection with the Omicron variant was seen earlier than in other areas, the number of new cases of infection has been decreasing, while there was a lag of approximately 2 weeks in the timing when the number of patients staying at hospitals or other facilities began to decrease. In addition, a similar trend was seen in the course of the infection, until the number of infected individuals at nursing welfare facilities began to decrease.
  • Even if the number of infected people nationwide continues to decline, for the time being, there is a possibility that the medical care provision system for mild and moderate cases will be tight in many areas, and the use of beds for severe cases will continue to increase due to the increase in the number of elderly people with severe illness. It was suggested that the death toll from the spread of infection this time may be centered on the elderly. It has been pointed out that some of them die without meeting the definition of severe illness due to the effects of not desiring highly invasive treatment or the worsening of an underlying disease. Attention should also be given to a possible increase in the number of infected individuals requiring hospitalization, as test-positive persons with an underlying disease may require hospitalization due to disease exacerbation by the infection, or elderly infected patients developing pneumonia including aspiration, even in cases where they do not have COVID-19 pneumonia.
  • In cases of difficult emergency transportation, non-COVID-19 suspected cases are also increasing, which puts a heavy burden on conventional medical care, especially emergency medical care.
Findings on the characteristics of the Omicron variant
  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 occur through the same opportunities as before (spending time indoors with insufficient ventilation, eating and drinking, etc.), and infection is considered to occur via the same routes as before (droplets, aerosol inhalation, contact infection, etc.).

  3. [Severity]

    It has been suggested that infection with the Omicron variant may present a relatively lower risk of hospitalization and aggravation than does the Delta variant. However, the number of cases of hospitalization due to the Omicron variant infection has already increased.

  4. [Duration of viral shedding]

    Viral shedding in individuals infected with the Omicron variant decreases over time, regardless of vaccination status. In patients with symptoms, it has been shown that the possibility of viral shedding after Day 10 (when the date of onset is regarded as Day 0) is as low as in the case of infection with the conventional strain. In patients with no symptoms, it has been shown that the possibility of viral shedding is low 8 days after the date of diagnosis.

  5. [Vaccine effect]

    For infection with the Omicron variant, the preventive effect of a first vaccination against disease onset is markedly reduced, but its preventive effect on hospitalization is maintained at a certain level. It has also been reported from overseas that a booster shot improves the preventive effects against disease onset and hospitalization for infection with the Omicron variant. There was also a preliminary report of a case-control study on the efficacy of COVID-19 vaccines against the Omicron variant in Japan.

  6. [BA.2 lineage]

    In some areas overseas, the number of cases of infection with the BA.2 lineage is increasing. Currently, the mainstream of the Omicron variant in Japan is the BA.1 lineage, but the BA.2 lineage has also been detected in quarantine and in Japan. Monitoring must be continued through a certain number of genome analyses. Analyses of the effective reproduction number, risk of domestic secondary infection, and other indices have shown that the infectivity of the BA.2 lineage is higher than that of the BA.1 lineage. According to a report from Denmark, there is no difference in the risk of hospitalization between the BA.1 lineage and the BA.2 lineage, in terms of severity. In addition, a report from the UK says that there is no difference in the preventive effect of vaccination between these lineages.

Efforts based on the spread of infection due to the Omicron variant
  1. [Surveillance in areas where infection is rapidly spreading]

    Effective and appropriate surveillance must be considered in order to understand the trends of occurrence. Regarding the monitoring system for mutant strains, it is necessary to continue monitoring trends by genome surveillance in regions where a strain has been replaced with the Omicron variant. For severe cases, clusters, or other applicable cases, confirmation by PCR test for mutant strains and whole-genome analysis is required.

  2. [Monitoring system for mutant strains in Japan]

    While the infection is spreading nationwide, it is necessary to maintain a surveillance system according to the local infection status, including the situation regarding replacement with the Omicron variant. For severe patients, clusters, or other applicable cases, a genome analysis should also be performed to identify variants such as the Delta variant.

  3. [Measures taken by local governments]

    Based on the infection status of the region and forecasts of the numbers of infected cases and severe cases, local governments must work flexibly to secure the required number of beds and healthcare professionals, secure the functions of public health centers, which are indispensable for local communities, along with support for strengthening the healthcare center system, and establish home-visit and online medical care systems for home care recipients. At that time, it is necessary to secure a system for prompt administration of oral therapeutic drugs and neutralizing antibody drugs, for patients at risk of developing severe disease, such as elderly patients and patients with underlying diseases.

    Since patients with acute diseases other than COVID-19 who require emergency transportation often appear during the winter, attention should be given to the balance between medical care for COVID-19 and regular medical care. If the infection spreads rapidly, it will be necessary to secure prompt access to consultation and condition monitoring for those at a higher risk of developing severe disease. In addition, a system must be established that allows COVID-19 patients with an underlying disease to continue treatment for the underlying disease.

    Implementation of efficient public health center operations are required, based on the recently issued administrative notice, such as prioritization of health observation and streamlining the handling of patient outbreak notifications. In addition, the optimization of measures based on the characteristics of the epidemic strain needs to be examined.

  4. [Reinforcement of information provision to persons who have not been vaccinated or who are eligible for booster vaccination]

    Local governments are required to promote the provision of information on vaccination. Booster vaccinations, which have already been started, must also be implemented steadily, along with vaccinations for unvaccinated persons. The number of infected individuals among the elderly may continue to increase in the future. Therefore, it is necessary to further accelerate vaccinations for the elderly and other eligible persons, and also to successively provide vaccination services ahead of the original schedule for the general public as well, as much as possible. Vaccination of children from 5 to 11 years old is necessary as a special temporary vaccination, and it is necessary to proceed with vaccination in the future taking into account that the obligation to make efforts does not apply to these children.

  5. [Quarantine measures]

    It is necessary to verify the epidemic situation of mutant strains such as Omicron variant in Japan and overseas. For individuals found to be positive by an entrance test, a whole-genome analysis should continue to be performed, to monitor the strains that are spreading 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 Omicron variant.

  • In many areas, the numbers of persons who are positive for the COVID-19 and in close contact with infected individuals are increasing at schools, kindergartens, nursery schools, etc. Local governments need to actively promote vaccination for teachers, childcare workers, and the other staff at such facilities. It is also necessary to consider securing educational opportunities through multiple measures including staggered attendance and online lessons, and maintaining social functions. At the same time, infection control measures must also be thoroughly implemented at home.
  • At nursing welfare facilities, promotion of booster shots for residents and staff, as well as aggressive testing for staff is required. For infection control and medical care at facilities, external support is important.
  • At workplaces, it is necessary to promptly review business continuity plans, and to reduce staff attendance at workplaces and opportunities for contact by utilizing telework, promoting the taking of time off, and through other measures, so that social functions can be maintained. Thorough health management and active promotion of occupational booster vaccinations for workers are also needed.
It is essential to widely share the current infection status with citizens and business operators, and cooperate toward preventing the spread of infection.
  • Basic preventative measures are still effective against infection with the Omicron variant. Therefore, administrative officers, business operators, and citizens should 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, because the Omicron variant is highly transmissible. Booster vaccinations are also effective in preventing disease aggravation/onset.
  • When going out, it is necessary to avoid situations/places with a high risk of infection such as crowds, and large gatherings either with or without shouting/loud speaking in poorly ventilated spaces. 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 carried out in a small group, without speaking to the extent possible, in principle, and the wearing of masks should be ensured at all times, except while eating and drinking.
  • In order to protect the lives of both ourselves and our families, and at the same time, to prevent the spread of infection due to the Omicron variant, it is necessary to refrain from going out if you feel a little unwell, such as a mild fever or fatigue, and to consult a physician and undergo tests according to government policy.

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

 

Copyright 1998 National Institute of Infectious Diseases, Japan