When will the 8th wave of the new coronavirus come? Experts analyze the scale of the infection

At the timing when the "7th wave" of the new corona has finally subsided, there is already talk of "the 8th wave is coming."

Will the 8th wave really come, and if so, when and how big will it be?

And how should we prepare?

Now that the number of infected people is bottoming out, we interviewed experts.

Experts feel a sense of crisis in the “eighth wave”

"There is a considerable sense of crisis regarding the coronavirus among experts.

" If

this

is combined with an influenza epidemic, there is a risk that the medical system will be even more burdened.”

Experts have been making statements expressing a sense of crisis about the "eighth wave" of the spread of infection.

At an expert meeting of the Ministry of Health, Labor and Welfare on the 12th of this month, a discussion was held on the 8th wave.

After the meeting, chairman Takaji Wakita pointed out that overseas, the number of infected people and the number of hospitalized people is at the same level as the wave of infections so far, or even larger.

On top of that, he said, ``There is no doubt that infection will occur in Japan, and in a situation where strong restrictions on movement are difficult to implement, there is an argument that we should start thinking about what measures can be taken when a medical crisis occurs. there was," he said.

On the 13th, chairman Omi of the subcommittee also said, "Medical experts have expressed a sense of crisis that the new corona alone may cause an infection that greatly exceeds the seventh wave. In Europe, the vaccination rate. The number of people infected with the virus is high, and the proportion of people who are naturally infected is much higher than in Japan. , We share the recognition that there is a risk of a fairly large spread of corona infection, and if this is combined with an influenza epidemic, there is a risk that the medical system will be further burdened."

Many people should have immunity, but it is spreading in Europe

Chairman Omi and other experts have a sense of crisis about the "8th wave" because while the number of new infections worldwide continues to decline, many people are already infected and have immunity. The number of infected people and hospitalizations is increasing in Europe, where there are supposed to be many people.

According to the site "Our World in Data" operated by researchers at the University of Oxford, England, in Germany, the number of new infections per million population was 3,000 in late March, and then in late July. After reaching 1,100 in 2010, the number had dropped to about 350 in early September, but has exceeded 1,000 again since early this month.

According to the materials submitted by Professor Hiroshi Nishiura of Kyoto University to the Ministry of Health, Labor and Welfare's expert meeting, in Germany, the number of hospitalized patients has increased sharply since late September, and last year, when the delta strain infection spread, Omicron It is said that the stock's "BA.1" has spread and may exceed the spring peak.

In France, after experiencing an extremely large spread of infections of 5,400 per million population in late January, there were times when it reached about 2,000 in late May and early July, but 240 in early September. reduced to the size of a person.

It turned to an increase, and there were about 840 people in the middle of this month.

In Europe, various regulations that have been implemented as a countermeasure against corona are being relaxed.

In Japan as well, border measures have been greatly eased from the 11th of this month, the limit on the number of people entering the country has been lifted, and nationwide travel support has started, and people-to-people contact is increasing. I am afraid that it will increase to

The number of infected people in Japan “bottomed out”

In Japan, we are starting to see signs that the number of infected people is bottoming out.

In the seventh wave caused by Omicron strain BA.5, the number of infected people continued to decline for almost two months after peaking in late August.

The average weekly number of infected people nationwide decreased from about 227,000 on August 24th to about 26,000 on October 11th.

Recently, however, the number has been flat or increasing, reaching approximately 31,600 on October 17.

Professor Kazuhiro Tateda of Toho University, who is a member of the government's subcommittee on new coronavirus countermeasures, said, ``There are signs that the decline has bottomed out in many areas. In addition, with the start of nationwide travel assistance and the easing of border measures, opportunities for person-to-person contact have increased, increasing the risk of an increase in the number of infected people. We have to keep an eye on whether it will stop declining and increase."

“8th Wave” When?

What is the scale?

When will the next “8th wave” of the spread of infection come?

According to Professor Nishiura of Kyoto University, looking at data from Europe, the "eighth wave" will arrive in Japan in the not too distant future.

(Professor Nishiura)

"We can see from European data that the 8th wave is right in front of us, and its scale is likely to be quite large. There are messages such as promoting relaxation and not having to wear masks. It is a situation where there is no sense of crisis."

Professor Akimasa Hirata of Nagoya Institute of Technology says that predictions using AI (artificial intelligence) may start increasing from the end of the year to the beginning of the new year.

Professor Hirata used AI to predict the future number of infected people based on the effects of both the immunity acquired by vaccination and the immunity acquired by being infected.

▽ Assuming that the number of people has almost returned to the state before the spread of the new coronavirus, and that people's behavior such as holding dinners and wearing masks will continue to be as thorough as it is now, It is predicted that there will be no significant increase in the number of infected people in the future.

▽ If people's activities such as year-end parties become active during the year-end and New Year holidays, the average number of new infections per day in Tokyo will be about 10,300 per week from mid to late January next year (2023). predicted to reach.

▽ In addition, assuming that actions have been relaxed other than the year-end and New Year holidays, it is predicted that the number of infected people will begin to increase from mid-December and will reach more than 14,000 from mid-January to late January.

Professor Hirata said, ``Vaccines have progressed, and many people were infected in the 'seventh wave,' so it is believed that many people have maintained a certain level of immunity. If the behavior continues, the next wave of infections may be relatively contained.On the other hand, if we take off our masks and have more immodest dinners, the number of infected people will increase. There is a risk that the number of infections will increase.It can be said that the infection can be spread or suppressed depending on our actions this year-end and New Year holidays."

It's just that this prediction doesn't consider the possibility of a new mutant virus.

“8th wave” also Omicron stock?

What kind of mutated virus will be mainstream if the next infection expansion happens?

Professor Nishiura of Kyoto University reported at an expert meeting of the Ministry of Health, Labor and Welfare on September 21, based on overseas research, that the speed at which Omicron strains mutate is abnormally fast.

And he commented, "Although there is always the possibility of a highly mutated mutant virus, it is predicted that the next wave of epidemics will be caused by variants of the Omicron strain."

In Germany and France, where infections are spreading again, "BA.5" accounts for about 90% as of early October.

In Japan, too, the "seventh wave" has become mainstream, and in Germany and France, where it dominated for several months, causing a resurgence of infections.

Atsuro Hamada, a specially appointed professor at Tokyo Medical University who is familiar with the situation of overseas infections, says that there are two main types of mutated viruses that could cause an "eighth wave."

One is the spread of infection by "BA.5", the same as the one that caused the "seventh wave".

(Professor Hamada)

“In Europe, the BA.5 epidemic has rekindled, and the embers are beginning to spread. As the weather gets colder, the epidemic will reignite, and it is expected to become an 'eighth wave.'"The

other is a case where a new mutated virus is introduced from overseas and the infection spreads.

Professor Hamada pointed out that one of the mutated viruses of concern is the spread of a type of virus called "XBB" in Singapore and other countries.

"XBB" is a combination of multiple types of viruses in the Omicron strain, and according to Singapore's Ministry of Health data, it was 6% as of September, and 54% in the week to the 9th of this month. %.

Partly due to the impact of this mutated virus, the number of infected people per million population in Singapore increased from about 340 in early September to over 1,500 in the middle of this month.

(Professor Hamada)

"If another type of Omicron strain enters Japan, there is a possibility that it will expand beyond the previous 'BA.5'."

In addition, other mutant viruses have been detected.

In the United States, according to the CDC = Center for Disease Control, as of the 15th of this month, ▽ Omicron strain "BA.5" continues to account for 67.9%, but ▽ "BA.4" derived "BA. 4.6" is 12.2%, ▽"BQ.1.1" and "BQ.1" are 5.7% each, ▽"BA.2.75.2" is 1.4%, and "BA.2.75" is 1.3%. It's a kind of, but the type of mutation virus is increasing.

Among these, the "BQ.1" lineage virus is a virus in which "BA.5" has undergone further mutations.

In addition, 'BA.2.75.2' has been detected in the United States, India, and European countries, and three more mutations have been added to 'BA.2.75', which has been mutated by 'BA.2'.

The nature of these mutant viruses is not yet clear, but when analyzed using human blood, it has been reported that immune function is lower than that of "BA.5".

According to Professor Hamada, although it is unlikely that these mutant viruses will change the severity of infection significantly compared to BA. At the same time, it is necessary to pay attention to the possibility that it may spread in Japan.

(Professor Hamada)

“The mutated viruses that are emerging now are those that have changed within the Omicron strain, so it is unlikely that the severity will increase significantly. As expected, a drastic change is unlikely given the current situation.In the past two years, shortly after the winter epidemic spread in Europe and the United States, the mutated virus reached Japan. We saw the situation coming in, but now that border measures have been relaxed, we have to think about the fact that the epidemic will spread in Japan immediately after the epidemic in Europe and the United States. should not"

No change in measures to be taken

Opinions differ on the timing and scale of the pandemic, but experts all agree that preparations for an "eighth wave" are necessary.

Furthermore, it has been pointed out that there is a possibility of a simultaneous epidemic with influenza this winter.

However, the measures we should take will not change significantly.

▽ 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.

And Professor Hamada says that vaccination is important once again, no matter which mutation virus spreads.

(Professor Hamada)

"The important point is to get the Omicron strain vaccine, which is starting now. It will increase your immunity not only to the Omicron strain but also to the new coronavirus in general, so I would like you to take this vaccination."