64th meeting of the COVID-19 advisory board of Ministry of Health, Labour and Welfare (December 22, 2021).  Material 1

Evaluation of the latest infection status, etc.

Infection status

• The number of new cases of infection nationwide (by the reporting date) remains at a very low level of about 0.9 per 100,000 in the most recent week, and in some regions there continue to be days with no new cases of infection. On the other hand, there are some areas where the spread of infection is still ongoing. In addition, there is a temporary increase in the number of patients in some regions due to clusters at the workplace, social welfare facilities, and primary schools, as well as the occurrence of cases with an unknown route of infection. The most recent week increased from the previous week to 1.35, with 1 or more continuing for more than 2 weeks.

  Effective reproduction number:On a national basis, the most recent number is above 1 at 1.11 (as of December 5). The figure is 1.23 in the Tokyo metro area and 1.02 in the Kansai area.

Future outlook and measures to be taken

• Since the Omicron variant was first reported to WHO from South Africa on November 24, cases of infection have been reported in many countries and so-called community-acquired infection has been confirmed in several countries. In Japan, genomic analysis has confirmed that many of those who tested positive for corona virus at border-control on return to Japan had the Omicron variant. In addition, the Omicron variant was confirmed in three people who had no history of overseas travel, and whose relationship with identified cases of the Omicron variant has not been confirmed. In the future, it should be assumed that the infection will spread rapidly.
• Although experimental evaluation of the properties and epidemiological information on the Omicron variant are limited, announcements and preprint article from WHO and various countries indicate high infectivity/transmissibility, risk of re-infection, and potential reduction of the preventive effect of vaccines or the effect of some therapeutic drugs. On the other hand, despite the lack of sufficient knowledge regarding its severity, we must be aware of the possibility that the medical care provision system will be suddenly strained due to the rapid spread of infection.
• To focus on the border-control measures against the Omicron variant and to strengthen the surveillance system in Japan, it is necessary to continue to administer PCR screening for variants and whole genome analysis of all positive individuals, particularly positive individuals who have traveled abroad. It is also necessary to continue to collect and analyze WHO and overseas trends, as well as clinical, epidemiological, and virological information. Based on evaluation of the infectivity, severity, and impact on vaccine efficacy of the Omicron variant by the National Institute of Infectious Diseases, as well as the status of occurrence in Japan, it will be necessary to inform the citizens of the need to shift the focus from border measures to domestic measures, in order to prevent the rapid spread of infection in Japan. In addition, when cases of infection caused by the Omicron variant occur in Japan, it is recommended that those who shared the same space as the cases with Omicron variant infection should undergo a wide range of tests regardless of whether they wore a mask or the duration of contact. Moreover, it is necessary to start taking “comprehensive measures to strengthen prevention, examination and early treatment,” including the government’s recent acceleration of vaccination, start of oral therapeutic drugs and strengthening of the examination system, as well as to promote strengthening of the medical care provision system and the public health system according to the situation of infection.
• The number of new cases of infection is still very low across the country, but is increasing. The nighttime population is also increasing, not only in urban areas but over wide areas. The nighttime population in Tokyo in particular is near the highest recorded level at the end of the last October. From now, the temperature will further decrease, and indoor activities will increase. In addition, annual vents such as year-end parties, Christmas and New Year holidays will increase exchanges between people who do not usually meet, and as well as the movement of people going home toward the end of the year and the beginning of the year, which may rapidly spread infections. For this reason, it is necessary to refrain from activities with a high risk of infection, and limit activities to as few people as possible.
• Amid concerns about the spread of the Omicron variant, it is especially necessary to promote vaccination of unvaccinated people, and local governments must enhance the communication of information to those who still have to be vaccinated. At the same time, the booster vaccination that started in December must also be steadily implemented. In doing so, it is necessary to smoothly carry out the acceleration of the schedule for healthcare professionals and the elderly at high risk of becoming seriously ill, based on the above-mentioned reinforcement measures.
• The transmission of infection by the Delta variant is still ongoing, and attention should be paid to the spread of infection triggered by the coming year-end and New Year holidays. It is also necessary to act with the recognition that the spread of the Omicron variant in Japan should be assumed. Therefore, it is important to continue basic anti-infection measures such as the correct way of wearing masks, hand washing, avoiding the three Cs, and ventilation among all people, including those who are vaccinated. These basic anti-infection measures are also recommended for the Omicron variant. It is also important to refrain from going out and proactively see a doctor if even slightly ill, such as with mild fever or fatigue, to undergo the necessary examinations. It is also necessary to select third party-certified restaurants when eating and drinking out, to wear a mask when not eating or drinking, and to avoid crowded places with a high risk of infection when going out. In particular, considering that homecoming and travel create opportunities for contacts that do not occur on a daily basis, in addition to receiving free tests in prefectures for those who cannot get vaccinated, people must refrain from traveling across prefectures when symptoms such as fever are present.

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