国立感染症研究所

62th meeting of the COVID-19 advisory board of Ministry of Health, Labour and Welfare (December 8, 2021).  Material 1

 

Evaluation of the latest infection status, etc.

Infection status

  • The number of new cases of infection nationwide (based on the date of reporting) has been decreasing, and the number per 100,000 population has been approximately 0.6 in the last week, the lowest since the summer of last year. However, the ratio of this week to last week was 1.11, showing an upward trend. The numbers of patients receiving treatment, severe patients, and deaths continue to be at a low level.

    Effective reproduction number:On a national basis, the most recent number remains below 1 at 0.87 (as of November 21), with values of 0.91 in the Tokyo metro area and 0.74 in the Kansai area.

Future outlook and measures to be taken

  • Patients infected with the new variant (Omicron variant) have been reported in 57 countries including the United States and European countries by December 7 according to WHO, which raises concerns about the spread of the infection. Genomic analysis also confirmed the Omicron variant in 3 persons from overseas who were found to be positive for corona virus during quarantine. Although there is no experimental evaluation of the properties of the Omicron variant or sufficient information for epidemiological evaluation, there are concerns about the high infectivity/transmissibility, the risk of reinfection, and its effects on vaccines and therapeutic drugs. Sufficient information on severity has not been also obtained. To focus on the border-control measures against the Omicron variant and to strengthen the surveillance system in Japan, it is required to administer PCR screening for variants and reinforce 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, and to take appropriate measures based on evaluation of the infectivity, severity, and impact on vaccine efficacy of the Omicron variant by the National Institute of Infectious Diseases.
  • Although the number of new cases of infection nationwide is at a very low level, the spread of infection is still ongoing. In some regions, there is a temporary increase due to clusters at the workplace and in social welfare facilities, as well as the occurrence of cases with an unknown route of infection. There is therefore concern that the decreasing trend may stop. There are also regions where the nighttime population is increasing, especially in urban areas. Indoor activities will increase as it gets colder towards the end of the year, and annual events such as year-end parties and the Christmas and new year holidays, are expected to cause a further increase in socioeconomic activities. Therefore, it is necessary to carefully monitor the number of infected patients in the days ahead.
  • Approximately 77% of the country's population has been fully vaccinated with two doses, and approximately 72% of those aged 12 to 19 years have been vaccinated with two dose. To further increase the vaccination rates, it is necessary to promote vaccination of unvaccinated people, and local governments must enhance the communication of information to those who still have to be vaccinated. It is also necessary to steadily implement additional vaccination, starting in December, for those who wish to receive it.
  • Although the infection transmission level is low, it is still ongoing and attention should be paid to the spread of infection in the future. Therefore, it is important to continue basic anti-infection measures such as the correct wearing of 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 expected that opportunities for eating and drinking such as year-end parties will increase towards the end of the year. On such occasions, it is necessary to select third party-certified restaurants when eating or drinking, 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 provide opportunities for contacts that do not occur on a daily basis, people must refrain from traveling across prefectures when symptoms such as fever are present. It is also important to proactively see a doctor for symptoms such as mild fever and fatigue to undergo the necessary examinations.
  • To prevent the spread of infection, it is necessary to thoroughly implement active epidemiological studies on cases of an unknown route of infection. In addition, active measures using a broad range of tests are required for infection control at social welfare facilities and medical institutions.

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

 

Copyright 1998 National Institute of Infectious Diseases, Japan

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