New Corona “8th wave” New Year’s holidays? What we have learned [12/9]

The "eighth wave" of the new corona, which has continued to increase since October.

However, the number of infected people across the country has not increased explosively, and has remained almost flat, repeating slight increases and decreases.

Is this the peak and will it start to decline?

How will the infection situation change over the year-end and New Year holidays?

(as of December 9)

The "8th wave" will remain flat, and in the future...

The number of people infected with the new corona per day was 149,383 nationwide on December 7, the highest in the "8th wave".

The number of people who died is also increasing, and it is 243 people on December 8th.

However, the weekly average number of infected people per day has remained flat since the beginning of December.

On December 7, an expert meeting of the Ministry of Health, Labor and Welfare pointed out that ``the rate of increase continues to slow nationwide, and is currently leveling off.''

How should we look at the current situation?

A clue is the status of the mutated virus that is the mainstream of infection.

Currently, the mainstream is the Omicron stock "BA.5".

It is the same as what caused the "seventh wave" of this summer.

Experts believe that the ``8th wave'' so far is a rekindling of ``BA.5,'' which remained in the city.

In fact, the "8th wave" spread from areas such as Hokkaido and Tohoku, where the number of infected people in the "7th wave" was relatively small.

Now, the number of infected people is believed to be leveling off as the number of infected people with "BA.5" is gradually subsiding.

Now, new mutated viruses such as the "BQ.1" lineage, a type of Omicron strain that could become the next mainstream, are about to start increasing, and there are concerns that they will spread further.

(Takashi Wakita, Chairman of the Ministry of Health, Labor and Welfare Experts' Meeting)

“In Hokkaido, Tohoku, and Hokuriku Koshinetsu, where the spread of infection was relatively early, it has peaked out or is declining. ``BA.5'' is currently the center, but ``BQ.1'' is gradually increasing. It is thought that there will be an impact when this ratio increases further.”

What will happen with the expansion of new mutated viruses?

Rapid increase in hospitalization overseas

Currently, we are seeing more and more detections of

▽ ``BQ.1'', which has a mutation in the spike protein part of ▽ ``BA.5'', and

▽ ``BQ.1.1'', which has further mutations.

Both of these viruses have a strong ability to bypass the immune system, raising concerns about the spread of infection.

"BQ.1" and "BQ.1.1" are collectively called the "BQ.1" system.

According to data from the Tokyo metropolitan government, 76.7% of the mutant viruses whose genomes were analyzed were ``BA.5'' in the first month of November, but it was on the decline, with ``BQ. 1.1” is gradually increasing to 7.5%.

In the week ending November 21st, ``BA.5'' was 73.5%, but ``BQ.1'' was 2.6% and ``BQ.1.1'' was 9.3%.

Overseas, where the "BQ.1" strain has increased first, the infection is spreading again and the number of severe cases is increasing.

According to the ECDC = European Center for Disease Control and Prevention, the percentage of "BQ.1" strains

has exceeded half in France since the beginning of November, and in

Spain it has exceeded 75% in mid-November. ,

as of late November, it has become the most mutated virus in seven European countries.

While it is said that the increase in the number of "BQ.1" strains does not necessarily lead to a worsening of the infection situation, it is said that in some countries the infection spreads and the number of people who become seriously ill is increasing.

Also, according to the CDC = Center for Disease Control in the United States, in the United States, "BQ.1.1" is 31.9% and "BQ.1" is 30.9% in the week until December 3, while " BA.5" decreased to 13.8%.

In addition, the number of new infections increased to about 459,000 in the week ending December 7, up from about 307,000 in the previous week, and there were 2,981 deaths in the week ending December 7. people, up from 1,844 the previous week.

(Specially appointed professor Atsuro Hamada of Tokyo Medical University, who is familiar with the situation of overseas infections)

"In the United States, the 'BQ.1' strain has reached 60%, and the number of hospitalized patients has increased especially since the Thanksgiving holiday in late November. In Europe, there are several countries where the number of "BQ.1" strains is increasing, and the number of severely ill patients is increasing.According to the data, there are countries where the number of infected people has not increased so much, but they are capturing mildly infected people. In Japan, the number of "BQ.1" strains has not increased so much, but it is expected that it will spread quickly. It is possible, and we need to assume that the number of new infections and the number of severe cases will increase in Japan as well.”

Year-end party, homecoming... from now on, it depends on what you do

It is predicted that the proportion of "BQ.1" strains in Japan will increase in the future.

According to the materials presented at the Ministry of Health, Labor and Welfare expert meeting on December 7 by Director Motoi Suzuki of the Infectious Disease Epidemiology Center of the National Institute of Infectious Diseases,

▽ "BA.5" was 54% in the week until December 11.

▽ ``BQ.1'' strain is estimated to be 36%,

▽

``BA.2.75'' 8%, and

▽ ``XBB'' 3%.

It is predicted that the number of ``BQ.1'' strains will gradually increase, although it will not match the speed of increase when ``BA.5'' caused the spread of infection this summer.

A group led by Professor Akimasa Hirata of Nagoya Institute of Technology uses AI (artificial intelligence) to monitor the status of new mutated viruses, the status of infections until December 5, the status of vaccinations, and drinking parties that have appeared on Twitter. In addition to information such as the status of the event, we predicted the future infection status.

The average number of new infections per day in Tokyo per week was about 12,000 as of early December, but assuming that the infectiousness of the new mutated virus is 1.2 times, the number of year-end parties will be limited. If social activity is modest, such as when it is on the decline, it will rise gradually toward the beginning of the year, and will peak at about 19,000 in early January.

On the other hand, if the social activities were large, it was estimated that the number would exceed 20,000 in late December and reach about 28,000 in early January.

(Professor Hirata, Nagoya Institute of Technology)

“Future changes in the number of infected people will depend on our actions. On the other hand, there is a good chance that there will be more people interacting during the year-end and New Year holidays, such as year-end parties, so there is a good chance that it will turn upward.Analyzing social media posts, drinking parties and other events will be held from around the end of November. It's increasing, and I think there will be more opportunities to meet old friends in the future, so there will be more opportunities for people to come into contact with each other. There is a possibility that the infection situation will be equivalent to the 'seventh wave'."

Specially appointed professor Hamada of Tokyo Medical University pointed out that an influx from overseas should also be assumed.

Professor Hamada said that it is possible that China will change its "zero corona policy" and that the number of tourists to Japan will increase in the future, which may affect the infection status in Japan.

He also pointed out that there are a number of cases of returnees from Qatar, where the soccer World Cup and the Qatar tournament are being held, who have been confirmed to be infected by quarantine at the airport.

(Professor Hamada, Tokyo Medical University)

"It is thought that there was a situation where the new corona was likely to spread at the venues of the World Cup. I would like you to actively take tests for the new coronavirus, even if it is from the beginning."

Beware of the simultaneous epidemic of influenza

It is also pointed out that the influenza epidemic may spread in the future.

The number of patients per medical institution was 0.13 nationwide in the week until December 4, which is well below the "1" that is considered to be the epidemic.

Since the spread of the new coronavirus, influenza infection did not spread in 2020 and last year (2021), but in the week until December 4, 38 prefectures reported cases. .

According to the Ministry of Health, Labor and Welfare's expert meeting, although the influenza epidemic situation remains low, caution is required as classes are being closed sporadically, mainly in the Kansai region.

In addition, the WHO = World Health Organization announced on November 28 that ``influenza infections are increasing worldwide,'' and points out that the epidemic is expanding rapidly, especially in North America.

Professor Hamada said, ``The number of people infected with influenza is increasing in the United States, the United Kingdom, Portugal, and Germany. We have to be careful because there is," he said.

No change in measures to be taken

As the year-end and New Year holidays approach, I think that there are many people who are thinking about having a year-end party this year, or thinking about returning to their parents' homes.

An expert meeting of the Ministry of Health, Labor and Welfare calls for the completion of vaccination against the Omicron strain by the end of the year, and calls for the use of antigen test kits that can be tested by oneself in preparation for infection.

And the important thing is to reconfirm the basic measures.

▽ If you have symptoms such as fever, do not go to school or work, and avoid contact with other people as much as possible.

rest is important.

▽Wear a mask when disinfecting your hands and when talking to people indoors at a close distance.

▽ Thoroughly ventilate restaurants and other establishments.

Professor Hamada emphasizes the importance of basic infection control measures and vaccination, saying that it is possible to have year-end parties, New Year parties, and even return home after taking sufficient infection control measures, given the current infection situation. doing.

(Specially Appointed Professor Hamada)

“The increase in movement during the year-end and New Year holidays is likely to lead to the spread of infection due to the increased opportunities for person-to-person contact. If you are planning to have a year-end party, New Year's party, or going home, please consider getting a booster vaccination as much as possible.The BQ. It is stronger than BQ.1, but it does not mean that the vaccine is completely ineffective.By inoculating the vaccine corresponding to the Omicron strain and raising the body's immunity, it will be effective in defending even if "BQ.1" enters the body. Masks are important to prevent the spread of the epidemic in winter, but the best trump card is to ventilate the room.I would like you to suppress the spread of the epidemic by opening the windows regularly. ”.