71th meeting of the COVID-19 advisory boardof Ministry of Health, Labour and Welfare (February 9, 2022). Material 1

Evaluation of the latest infection status, etc.

Infection status

• The number of new cases of infection (by date of report) nationwide increased continuously to approximately 505 per 100,000 in the latest week. However, at the same time, the ratio of new cases to that for the previous week is 1.19, indicating a continuous downward trend, with an increasing pace. Seen by age group, the proportion of patients in their 20s has decreased, while the proportions of patients under 10 years old and patients in their 60s and older has increased.
• Among the 35 prefectures that are currently under priority measures, Shimane, Hiroshima, Yamaguchi, Nagasaki, Kumamoto, Miyazaki, and Okinawa show a downward trend or a sign of bottoming out in the number of new cases of infection, with a ratio to that for the previous week of less than 1. Gunma is also showing signs of a decrease, with a ratio to that for the previous week of 0.99. In other prefectures, the ratio to that for the previous week is also on a downward trend, showing continuous slowing, with an increasing pace. In Okinawa, where the number of new cases of infection continues to decrease, all age groups are showing a decrease. Among prefectures where priority measures are not in force, Akita, Yamanashi, Tottori, and Ehime have a ratio to that for the previous week of less than 1.
• While the pace of increase in the number of new cases of infection is slowing down nationwide, the numbers of patients receiving treatment, severe patients, and deaths continue to increase.
• In the Tokyo metropolitan area and Kansai area, cases of infection with the Omicron variant have become dominant.

  Effective reproduction number: On a national basis, the most recent number is above 1 (1.07; as of January 24), while the figure stands at 1.09 in the Tokyo metropolitan area and 1.06 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 has increased continuously to approximately 459 (approximately 669 in Sapporo City), with a ratio to that for the previous week of 1.30. The infected individuals are mainly in their 30s or younger. The use rate of beds is approximately 30%.

2. Tohoku

   In Aomori, the number of new cases of infection has increased continuously to approximately 221, with a ratio to that for the previous week of 1.18. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 30%. In Yamagata and Fukushima, the number of new cases of infection has also increased continuously, to approximately 171 and 194, respectively. Both prefectures show an increase, with a ratio to that for the previous week of more than 1. The use rate of beds is slightly more than 40% in Yamagata and Fukushima.

3. North Kanto

   In Gunma, the number of new cases of infection is approximately 347, with a ratio to that for the previous week of less than 1 (0.99). The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly less than 60%. In Ibaraki and Tochigi, the number of new cases of infection has increased continuously, to approximately 346 and 300, respectively. Both prefectures show an increase, with a ratio to that for the previous week of more than 1. The use rate of beds is slightly more than 30% in Ibaraki and Tochigi.

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

   Tokyo continues to show an increase in the number of new cases of infection. The number has reached the highest value in Japan (approximately 926), with a ratio to that for the previous week of 1.21. The infected individuals are mainly in their 30s or younger, while the number of those aged less than 10 years is also increasing. The use rate of beds is slightly more than 50%, while the use rate of beds for severe patients is approximately 40%. In Saitama, Chiba, and Kanagawa, the number of new cases of infection has also increased continuously, to approximately 550, 537, and 613, respectively. All of these prefectures show an increase, with a ratio to that for the previous week of more than 1. The use rate of beds is slightly less than 70% in Saitama, slightly more than 60% in Chiba, and slightly less than 70% in Kanagawa. The use rate of beds for severe patients is approximately 40% in Kanagawa.

5. Chubu/Hokuriku

   In Ishikawa, the number of new cases of infection has increased continuously to approximately 297, with a ratio to that for the previous week of 1.20. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 50%. In Niigata and Nagano, the number of new cases of infection has also increased continuously, to approximately 156 and 193, respectively. The use rate of beds is slightly more than 30% in Niigata and slightly more than 90% in Nagano.

6. Chukyo/Tokai

   In Aichi, the number of new cases of infection has increased continuously to approximately 521, with a ratio to that for the previous week of 1.13. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 50%. In Gifu, Shizuoka, and Mie, the number of new cases of infection has also increased continuously, to approximately 302, 324, and 292, respectively. All of these prefectures show an increase, with a ratio to that for the previous week of more than 1. The use rate of beds is slightly more than 50% in Gifu and Shizuoka, and slightly less than 50% in Mie.

7. Kansai area

   In Osaka, the number of new cases of infection has increased continuously to approximately 871, with a ratio to that for the previous week of 1.15. The infected individuals are mainly in their 30s or younger. The use rate of beds is approximately 90%, while the use rate of beds for severe patients is slightly more than 40%. In Kyoto, Hyogo, and Wakayama, the number of new cases of infection has also increased continuously, to approximately 689, 714, and 387, respectively. All of these prefectures show an increase, with a ratio to that for the previous week of more than 1. The use rate of beds is slightly less than 60% in Kyoto and slightly more than 70% in Hyogo. The use rate of beds for severe patients is slightly more than 50% in Kyoto and slightly more than 20% in Hyogo.

8. Chugoku/Shikoku

   In Hiroshima, the number of new cases of infection is approximately 267, with a ratio to that for the previous week of less than 1 (0.81). 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 slightly more than 30%. In Shimane and Yamaguchi, the number of new cases of infection has also decreased to approximately 77 and 161, respectively, with a ratio to that for the previous week of less than 1 (0.89 and 0.85, respectively). In Okayama and Kagawa, the number of new cases of infection has increased continuously, to approximately 391 and 246, respectively. Both prefectures show a continuous increase, with a ratio to that for the previous week of more than 1. The use rate of beds is approximately 30% in Shimane, slightly more than 50% in Okayama, slightly more than 40% in Yamaguchi, and slightly more than 50% in Kagawa.

9. Kyushu

   In Fukuoka, the number of new cases of infection has increased continuously to approximately 642, with a ratio to that for the previous week of 1.17. The infected individuals are mainly in their 30s or younger. The use rate of beds is slightly more than 80%. In Saga, Oita, and Kagoshima, the number of new cases of infection has increased continuously, to approximately 432, 269, and 263, respectively. All of these prefectures show an increase, with a ratio to that for the previous week of more than 1. In Nagasaki, Kumamoto, and Miyazaki, the number of new cases of infection is 276, 344, and 213, respectively, with a ratio to that for the previous week of less than 1 (0.91, 0.85. and 0.86, respectively). The use rate of beds is slightly more than 30% in Saga, slightly more than 40% in Nagasaki and Miyazaki, slightly more than 60% in Kumamoto, slightly more than 40% in Oita, and slightly less than 60% in Kagoshima. The use rate of beds for severe patients is slightly more than 20% in Kumamoto.

10. Okinawa

    The number of new cases of infection is approximately 295, and the ratio to that for the previous week remains less than 1 (0.67). In the Yaeyama district, the increase is continuing. The newly 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 patients is slightly more than 50%.

< Areas other that the above >

1. In Iwate, Miyagi, Toyama, Fukui, Shiga, Nara, Tokushima, and Kochi, the number of new cases of infection is approximately 84, 198, 203, 200, 496, 516, 169, and 225, respectively. All of these prefectures show an increase, with a ratio to that for the previous week of more than 1. In Akita, Yamanashi, Tottori, and Ehime, the number of new cases of infection is 132, 235, 122, and 133, respectively, with a ratio to that for the previous week of less than 1 (0.82, 0.82, 0.65, and 0.87, respectively). The use rate of beds is slightly more than 40% in Iwate, slightly more than 30% in Miyagi, Akita, Toyama, and Tokushima, approximately 20% in Fukui, slightly more than 50% in Yamanashi, approximately 60% in Shiga, slightly more than 70% in Nara, slightly more than 20% in Tottori, slightly less than 40% in Ehime, and approximately 40% in Kochi.

Future outlook and measures to be taken

• The nationwide number of new cases of infection continues to increase, while its pace is slowing down. The infection still seems to occur at certain places, such as homes, schools, nursery schools, workplaces, and nursing welfare facilities. The nighttime population is generally decreasing in the areas under priority measures, although it is increasing in some areas. In some areas, the number of new cases of infection has been decreasing or stopped increasing. As its ratio to that for the previous week and the effective reproduction number by date of report are approaching 1 even in large cities, the number of new cases of infection may peak in the future. However, attention should be paid to the fact that possible discrepancies have been pointed out between the published data and the actual status, due to delayed reporting and a strained testing system, as well as the possibility that the number may increase again when the Omicron variant (BA.2) becomes dominant in the future.
• Individuals infected with the Delta variant, which is more likely to cause severe symptoms, are still being detected, although their number is decreasing, along with replacement by the Omicron variant. 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 new cases of infection decreases mainly among young people in many areas, medical care provision system and other types of service for mild and moderate patients will continue to remain strained for a while, and the possibility that there will be limited bed availability for severe patients will become higher, along with a possible increase in the number of elderly patients with severe symptoms. 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, even in cases where they do not have COVID-19 pneumonia.
• Each year, many cases of emergency transportation usually occur during this period. According to a status survey on cases of emergency transportation difficulties, cases of suspected non-COVID-19 have increased compared to cases of suspected COVID-19, in many municipalities. With a rapid increase in the number of cases of suspected COVID-19, cases of emergency transportation difficulties have exceeded those during the same period last year and during the spread of the infection last summer. There is already a significant burden on regular 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. As the obtained data indicates that the serial interval is shorter than the incubation period in individuals infected with the Omicron variant, its transmission before disease onset probably occurs to a certain extent, as in the case of infection with the conventional strain.

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 that a booster shot improves the preventive effects against disease onset and hospitalization for infection with the Omicron variant.

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. [Test/diagnosis and surveillance in areas with a rapid spread of infection]

   A test/diagnosis system and the processing of notifications to public health centers are becoming strained, and there are concerns regarding discrepancies between the published data and the actual status. It is necessary to consider effective and appropriate surveillance, in order to properly grasp the trend of occurrences. Tests and active epidemiological surveys should be prioritized based on the findings obtained thus far. Regarding free tests for people who are worried about infection and wish to undergo testing, attention should be paid to a rapid increase in demand for tests as well as test availability, and a system to ensure prioritized testing needs to be secured.

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. As 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. Furthermore, it is also necessary to establish a system that enables COVID-19 patients with an underlying disease to continue treatment for the underlying disease.

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.

5. [Quarantine measures]

   The waiting period after entering Japan has been further reduced from 10 days to 7 days. It is necessary to continue to verify future quarantine measures, while taking into account the prevalence of variants such as the 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. Based on the situation where the infection is spreading due to the Omicron variant, a proposal has just been made at the meeting of the Subcommittee on Novel Coronavirus Disease Control held on February 4. In situations/places where the infection is spreading, prevention measures based on the characteristics of the Omicron variant should be strengthened and thoroughly implemented.

• 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 nursing welfare facilities, promotion of booster vaccinations 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)