The number of new infections with the new coronavirus nationwide, which had been declining moderately for more than a month, turned to increase this week.
We organized the current situation and interviewed experts about why the number is increasing and whether the "7th wave" of infection has begun.
Increased for the first time in a month and a half
In the "sixth wave" of the spread of infection, the number of infected people increased sharply in January 2022, and the average number of infected people per week reached about 93,000 in early February, and then the number of infected people has continued to decrease gradually. I did.
However, according to NHK's summary, the number of newly infected people in the week up to March 30 was 1.15 times that of the previous week nationwide, and it turned from a decrease that lasted about a month and a half to an increasing trend.
The number of areas increased from the previous week has risen to 42 prefectures.
[Metropolitan area]
▽ 1.21 times in Tokyo ▽
0.95 times in Kanagawa prefecture ▽
1.17 times in Saitama prefecture
▽ 1.07 times in Chiba prefecture
[Kansai]
▽ 1.11 times in Osaka prefecture ▽
1.23 times in Kyoto prefecture ▽
1.11 times in Hyogo prefecture,
etc. It has become.
Among them are
▽ Akita prefecture 1.35 times
▽ Mie prefecture 1.47 times
▽ Saga prefecture 1.49 times
▽ Oita prefecture 1.45 times
▽ Kagoshima prefecture 1.74 times
▽ Okinawa prefecture 1.36 times
etc. There are also places where the target is getting bigger.
In Kagoshima Prefecture, on March 30, the number of infected people per day was 776, a record high for the second consecutive day.
The reason for the increase now is
Why is the number of infected people increasing now?
At the expert meeting of the Ministry of Health, Labor and Welfare held on March 30, it was pointed out that
▽ opportunities for contact with people at three consecutive holidays from March 19, graduation events and welcome and farewell parties that change every year.
▽ Since the priority measures such as prevention of spread were lifted by March 21, the number of people in downtown areas at night has increased nationwide
.
Along with this, the number of infected people in their twenties is increasing, and the rate of infection in restaurants is increasing.
The increase in infections in the active 20s has always been seen in the early stages of infection, and it tends to spread to a wide range of generations from there, so caution is required.
On the other hand, it is said that the infection of elderly people in long-term care welfare facilities and medical institutions is still continuing.
7th wave?
It should be noted that the expert meeting seems to have increased numerically in late March due to the effect of the three consecutive holidays when the number of examinations decreased, but the current increasing trend is infected. It is said that it is necessary to pay close attention to whether or not it will lead to re-expansion and rebound.
The number of new infections per day has nearly doubled from the peak of the 5th wave in the summer of 2021, although it has halved from the peak of the 6th wave.
It has been pointed out that it is still in the middle of the 6th wave, and experts point out that if it becomes the "7th wave" as it is, there is a possibility that the infection will spread more than before.
At a press conference on March 30, Takaji Wakita, chairman of the expert meeting, said, "The number of infected people has begun to increase a little in their 20s, and the rate of infection at restaurants is increasing. Also, the positive rate of tests in Tokyo and Osaka. It is possible that signs of rebound are beginning to appear, such as the rise in the number of people, but we are not in a situation where we can say that we have entered a period of spread of the infection. "
In addition, Professor Koji Wada of the International University of Health and Welfare, who is a member of the expert meeting, said, "If the spread continues in the midst of an unprecedented scale of infection, we do not expect a wave higher than the sixth wave to come. I have to do it. "
What will happen in the future
Regarding the future infection situation, the expert meeting says that there are factors that increase and suppress infection, and which one will be dominant in the balance.
As factors to increase the number, the expert meeting
cites
the increase in the number of people in the downtown area at night
and the replacement of the Omicron strain with "BA.2", which is said to be more infectious
. As
a result, the rate of the third vaccination has improved, the number of people who have been infected and have antibodies has increased, and
the temperature has risen, making it easier to ventilate
.
Increase factor 1 "Increase in the number of people in downtown at night"
Since the infection of the new coronavirus spreads through conversations without masks, the pattern of spreading the infection has been repeated after the number of people in the downtown area at night increased.
After the lifting of the priority measures, the number of people in downtown at night has increased almost nationwide.
Among them, the number of infections among young people who are active is increasing, and according to the data of the Ministry of Health, Labor and Welfare's system "HER-SYS" that collects information on infected people, the ratio of newly infected people in their 20s is nationwide. Then, it was about 13% after February, but gradually increased from the middle of March to about 16% to 17%.
In addition, according to data from Okinawa Prefecture, which currently has the highest number of infected people per population, the number of infected people in their 20s increased by 40% in the week leading up to the 27th of this month compared to the previous week, accounting for the total number of infected people. It is about 22%.
Increase factor 2 "Replacement with'BA.2'"
It has been pointed out that replacing Omicron strain with "BA.2", which is said to be more infectious, may lead to an increase in infection.
According to the National Institute of Infectious Diseases, "BA.2" accounted for around 20% in the week from March 7th, according to the results of coronavirus test conducted by a private inspection agency.
▽ March 28th this week Approximately 60% in the week
from the day
▽ .
In the United Kingdom and elsewhere, the replacement of BA2 has led to an increase in infections, and the number of seriously ill and dead people is also increasing.
Suppressive factor 1 "Improvement of the third vaccination rate"
At the beginning of January 2022, the third vaccination rate was less than 1% even for the elderly aged 65 and over, but as of March 31, the elderly aged 65 and over. More than 80% of the population has exceeded 40%, and it is expected that the younger generation will be further vaccinated in the future.
According to a study conducted by Nagasaki University and others, the effect of preventing the onset of the new coronavirus vaccine by the third vaccination is estimated to be 68.7% even when the Omicron strain spreads, and the expert meeting regained the effectiveness by the third vaccination. It is supposed to be.
In addition, it is pointed out that there are a certain number of people who have antibodies against the new coronavirus in the area where the infection spread significantly in the 6th wave, which may lead to the suppression of the spread of the infection in the future.
Suppressive factor 2 "Easy to ventilate due to rising temperature"
Ventilation has become an important measure because the new coronavirus is transmitted mainly through tiny flies that float in a closed room called "micro flies" or "aerosols".
In the future, expert meetings will make it easier to ventilate restaurants and other places due to rising temperatures, and reducing the amount of time spent indoors will also be considered as factors that curb the spread of infection.
Experts have stated that changes in these factors that increase and suppress infection affect the status of infection, and in order to control infection, steadily implement additional vaccinations, properly wear non-woven masks, and disinfect. It is necessary to take thorough measures such as avoiding ventilation and congestion.
Experts
Professor Wada of the International University of Health and Welfare said, "If the factors that lead to the suppression of infection, such as further promotion of vaccine booster in the younger generation, catch up, the rapid increase may be suppressed. I want you to receive it as soon as possible. If you feel sick, such as sore throat or fever, think that you are infected and do not meet people. "
Regarding future preparations, "It is necessary to prepare on the assumption that the 7th wave will come at some point. Especially in general medical institutions, patients who need treatment due to injury or illness are infected with corona. However, it is very important to create an environment where we can respond. There are an increasing number of cases where it is difficult to carry out emergency transportation if we cannot respond to ourselves and cannot be transferred to another hospital, which directly leads to the strain on general medical care. Based on the lessons learned from the wave, it is necessary to urgently re-examine and improve the medical system in each region. "
In addition, Chairman Wakita of the expert meeting said, "I think there are various opinions on infection control, but so far in Japan, we have taken measures if there are signs of tight medical care in order to reduce the number of seriously ill and fatalities. However, restricting behavior will cause great damage to the economy. In the current situation where priority measures have not been issued, measures to avoid infection risk without restraining economic activities and measures such as the third vaccination are taken firmly. In my opinion, if the infection spreads and medical pressure is sure to occur in the future, it is necessary to take measures to control the infection. In that case, various measures are required. The parties concerned should make a firm agreement and proceed. "