Possibility of simultaneous epidemic of new corona and influenza What is the situation?

The number of new coronaviruses has been on a downward trend since summer, border measures have been eased, and nationwide travel support has begun.

I can hear the voice that it's ok to take off the mask.

Among them, experts are concerned about the possibility that the new corona and influenza will be prevalent at the same time over the winter.

In the past two seasons since the emergence of the new corona, there have been no simultaneous epidemics, but what is different this year?

What could happen and how should we respond?

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New Corona and Influenza “Possibility of an epidemic is extremely high”

"It is extremely likely that the epidemic of the new corona will spread and the epidemic of seasonal influenza will occur in the half-year period from October to March next year.

" A document showing the outlook was submitted to the Ministry of Health, Labor and Welfare's expert meeting.

It was submitted by Professor Hitoshi Oshitani of Tohoku University, Professor Hiroshi Nishiura of Kyoto University, Director Motoi Suzuki of the Center for Epidemiology of Infectious Diseases of the National Institute of Infectious Diseases, and Director Takaji Wakita, who also chairs the expert meeting.

In response to this, the expert meeting pointed out, ``From autumn, influenza will spread earlier than usual, and there is concern that it will be a simultaneous epidemic with the new corona, and it is necessary to take measures assuming such a situation.'' .

Influenza epidemic not seen in past two years

Before the new corona infection started, seasonal flu was trending every winter.

It is estimated that 10 million people were infected in one season, and 20 million people were infected in a busy year.

Since the emergence of the new coronavirus, the number of flu patients has decreased sharply.

According to estimates by the National Institute of Infectious Diseases based on information from about 5,000 medical institutions nationwide, there were about 14,000 people from 2020 to 2021, and about 3,000 people from 2021 to 2022.

Influenza spreads throughout the year in tropical and subtropical populated areas such as Southeast Asia and Africa.

It has been thought that it will flow to each country due to the movement of people internationally and cause a large-scale epidemic in winter, when the environment for the spread of the virus is more likely to occur.

However, it is believed that the flu epidemic did not occur due to the restrictions on international movement of people due to corona measures and the decrease in person-to-person contact.

Why is this year the risk of a synchronous epidemic?

This is how things have changed this year.

Experts say the flu epidemic could strike for the first time in three years, including:

[Relaxation of border measures, etc.]

Many countries around the world, including Europe and the United States, have continued to ease restrictions on movement, such as border measures, since spring and summer this year, and international movement of people has increased significantly.

In Japan, from the 11th of this month, border measures will be greatly relaxed.

The upper limit on the number of people entering the country has been lifted, allowing free individual travel from overseas.

It is thought that the conditions for not only the new corona but also the influenza epidemic will be easier to prepare.

[Few people with influenza immunity]

Since influenza has not spread in Japan for the past two years, it is believed that the percentage of people who have acquired immunity to influenza after being infected is decreasing.

Every year, before the flu season begins, an "influenza susceptibility survey" is conducted nationwide based on the Vaccination Law to determine the proportion of people with antibodies to influenza.

According to it, the proportion of people who had antibodies to some type A influenza viruses was lower last summer than the previous year, the summer of 2020.

The results of this year are not yet known, but according to a document issued by an expert, it is possible that the influenza epidemic will become larger than usual due to the low antibody status.

[Epidemic in Australia in the Southern Hemisphere] In the Southern Hemisphere, Australia,

where the season is opposite to Japan and the timing of the influenza epidemic is shifted by half a year, the same influenza epidemic as before the spread of Corona occurred for the first time in two years. .

In Australia, the epidemic peaked in August every year, but this year it peaked in June, which means that the epidemic occurred early.

Based on these points, experts believe that an influenza epidemic will occur over the winter and may overlap with the "eighth wave" of Corona.

On the other hand, opportunities for person-to-person contact in Japan have not returned to what they were before the spread of the coronavirus, and it is believed that the scale of the influenza epidemic may not be as large as it once was.

Corona and flu simultaneous epidemic What kind of situation?

In the "7th wave" of the new corona, which became the largest spread of infection in Japan, nearly 12 million people were infected and about 13,500 people died in the three months from July to September this year. I was.

The fatality rate is 0.11%.

At its peak in late August, approximately 1.59 million infections were reported in a week.

The National Institute of Infectious Diseases estimates that the number of flu patients was about 12 million in the season from the fall of 2018 to the spring of 2019 before the spread of the new corona.

At its peak in late January, it is estimated that there were approximately 2.23 million patients per week.

According to a rough estimate by experts presented at an expert meeting of the Ministry of Health, Labor and Welfare in March 2022, the fatality rate of influenza is about 0.01% to 0.05%.

In the "seventh wave" of the new coronavirus this summer, patients rushed to medical institutions with fever outpatient clinics, and there were many cases where medical institutions and public health centers could not be contacted.

In addition, the utilization rate of the secured hospital beds has increased, making it difficult to be hospitalized in many areas, and it has become difficult for people at risk of becoming seriously ill to be transported by ambulance.

Experts are concerned that a similar situation, or even worse, could occur with the covid-19 and influenza epidemics.

The new corona and flu have similar symptoms such as fever and cough.

Symptoms such as sore throat and joint pain are also similar, and it is considered quite difficult to distinguish between the two based on symptoms alone without examination.

It is assumed that patients complaining of fever will rush to outpatient clinics at medical institutions in search of a diagnosis, and the situation will be imminent.

When the spread of the "eighth wave" of the new corona becomes large-scale, it becomes impossible to avoid the strain on medical institutions such as emergency services due to the overlapping of measures to deal with influenza.

In addition, every winter is a time when the number of cardiovascular diseases such as myocardial infarction increases due to a drop in temperature, and the burden on medical institutions increases. There are also concerns that it will become even bigger.

Professor Kazuhiro Tateda of Toho University, a member of the government's subcommittee, said, ``Fever patients are occurring at a level of more than 500,000 people nationwide every day, and this is the worst case in which outpatient treatment is more difficult than the seventh wave of this summer. We have to anticipate the situation,” he said.

Fever under the epidemic How should we respond?

So, if the new corona and influenza become prevalent at the same time and symptoms appear, how should we respond?

We asked Professor Ken Kosaka of Tohoku University, who is a member of the Ministry of Health, Labor and Welfare's expert meeting.

(Professor Kosaka)

"If you become aware of a fever during a simultaneous epidemic, you can't tell the difference just by looking at the symptoms. Now that you can buy an antigen test kit on the Internet, you may be able to make a judgment yourself. Influenza is difficult.It may be necessary for many local medical institutions to take the initiative in treating fever patients.

" ``It is necessary to have guidelines such as ``which medical institution to go to if you have a fever'' and ``what to do'' in an easy-to-understand manner

. Even with the coronavirus, if you take antipyretics, hydrate, and rest well, your symptoms will basically improve.It is also important to rest first.

” When thinking about it, he says that it will be important to see how much influenza is prevalent in the region.

(Professor Kosaka)

“The status of the influenza epidemic in the region is a big guideline.

"

We don't have a real-time grasp that is updated."

It becomes very important.”

Takaji Wakita, chairman of the Ministry of Health, Labor and Welfare Experts' Meeting, also said at a press conference after the expert meeting held on the 5th of this month, "In the midst of the simultaneous epidemic, what should each person do, such as visiting a medical institution if they develop a fever? It is important to show clearly what action should be taken.In addition, it is necessary to discuss how antiviral drugs such as the anti-influenza drug Tamiflu should be used."

What about vaccines?

What about the medical system?

In addition, how should we think about vaccination in preparation for the epidemic?

Both the new corona vaccine and the influenza vaccine are said to be highly effective in preventing infection to some extent and preventing aggravation.

Professor Kosaka is calling for influenza vaccinations along with the third and fourth vaccinations for the new corona.

(Professor Kosaka)

"There is no problem in getting both coronavirus and flu vaccines at the same time. Some medical institutions allow you to get vaccinated at the same time. It's important for us."

In addition, Professor Tateda of Toho University points out that it is important to establish a medical system to ensure that people who are at risk of becoming seriously ill can be examined using online medical care.

(Professor Tateda)

"In order to maintain a system that prioritizes medical care for people at high risk of developing severe symptoms, those who are not at risk and are likely to have mild symptoms should be recuperated at home and make good use of online medical care and follow-up centers. You can test for coronavirus at home with a simple test kit, but if it becomes possible to test for influenza at home as well, you will be asked if you should go to a medical institution or recuperate at home. We think it will be possible to make decisions more smoothly.”

No change in infection control measures to be taken

On the other hand, both the new coronavirus and influenza are respiratory infections, and the routes of infection are similar, so the measures to be taken do 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, etc.

Experts call for the importance of continuing these basic measures in order to reduce the scale of infection in the event of a simultaneous epidemic of the new coronavirus and influenza.