“It’s too early to talk about the epidemic”: Director of the Research Institute of Influenza - about the “revenge” of SARS after three years of the COVID-19 pandemic

— Dmitry Anatolyevich, against the background of the weakening of the coronavirus in Russia, the usual seasonal flu began to spread.

Experts talk about the appearance of the Egyptian strain, as well as swine and Hong Kong flu.

What other flu variants are currently circulating in Russia and is there a dominant variant?

- Indeed, an increase in the incidence of influenza and SARS is recorded in Russia, although it is too early to talk about the epidemic.

Most cases of influenza infection in our country are now caused by a variant of the influenza A (H1N1) virus, also called swine flu.

In 2009, this pathogen caused a pandemic, but now it has become a common seasonal virus that constantly circulates among people and comes to Russia every year.

- Did the experts manage to predict which variants of the influenza pathogen will spread this year?

Will the influenza vaccines released be effective?

- The forecast is based on observations of the circulation of viruses throughout the year, almost all over the world.

In particular, data on the rise in incidence in the Southern Hemisphere that preceded the spring-summer period are taken into account.

For example, this year there was a real influenza epidemic caused by the A (H3N2) virus.

It is he who is now predominantly distributed in most countries of the Northern Hemisphere - in the USA, Canada, European countries, where an influenza epidemic is already being recorded.

In Russia, the circulation of A (H3N2) is insignificant, but we are not yet at the peak of the incidence.

On the basis of observations, which, among other things, are being conducted by our institute, a forecast of WHO experts on the strain composition of influenza vaccines for the coming season is formed.

The data we currently have indicate that the influenza viruses circulating in the Northern Hemisphere are consistent with vaccine strains, which means that the prediction turned out to be correct.

- If a person gets sick not with the variant of the virus from which he was vaccinated, but with another one, will the vaccine help to transfer the disease more easily?

- Of course, vaccines provide maximum protection against exactly those variants of the virus for which they were created.

However, practice shows that there is also a cross-effect - even in the event of a discrepancy between the vaccine strain and the circulating version of the virus, vaccination still facilitates the course of the disease.

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Is there a universal flu vaccine being developed?

— Yes, work on such vaccines is being carried out in a number of countries, including Russia, including at our institute.

WHO has even identified the development of a universal vaccine as the main focus of work in the field of influenza vaccines.

Such a vaccine will protect against a wide range of strains and should ideally be given every few years rather than annually.

Unfortunately, so far the drugs brought to clinical trials have not shown the proper effectiveness.

Therefore, research continues, but over time, such drugs will undoubtedly appear - in favor of this is the scientific achievements that have already occurred in this area.

- How willingly do people get vaccinated against influenza, what collective immunity to influenza does Russia have today?

- In general, Russians are quite willing to get vaccinated against the flu.

The positive experience of influenza vaccination is affecting, because large-scale vaccination campaigns have been carried out for a long time, since 1996.

People see the effectiveness of such vaccination.

In terms of measuring herd immunity to influenza, of course, population immunity studies are constantly being conducted to evaluate the effectiveness of vaccines.

However, due to the high variability of the influenza virus, vaccines need to be updated regularly.

Every year, an updated strain composition is used, and the task is to ensure the maximum coverage of the population with vaccination, primarily people from risk groups.

Many years of experience in influenza vaccine prophylaxis, as well as the experience of vaccination against COVID-19, have shown that even if we do not prevent infection and the development of the disease, severe infections and deaths are much less common among vaccinated people.

- When is the peak of the influenza epidemiological season expected this year?

- Observations of more than one decade have shown that the peak incidence of influenza usually occurs at the end of December and January.

However, since the beginning of the pandemic and to this day, these patterns have been violated.

Therefore, we are now seeing such an early rise in the incidence of influenza and other acute respiratory viral infections in a number of countries.

We attribute the current rise, among other things, to the fact that now in most countries the 2020-2021 sanitary restrictions no longer apply.

In addition, during the COVID-19 pandemic, influenza could not compete with a new pathogen and practically retreated, primarily in the 2020-2021 season.

SARS-CoV-2 dominated the human population for two years due to the interference mechanism, when the presence and activity of one virus in the body blocks the development of other pathogens.

• Examination queue during the H1N1 influenza pandemic, New Delhi, 2009

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• © Parveen Negi/The India Today Group

But now SARS-CoV-2 is no longer as widespread as in the first two years of the pandemic, since most people are immune to this virus - either as a result of vaccination, or after illness, or as a result of both.

Therefore, influenza viruses can take "revenge", which we are now seeing.

- What is the seasonality of influenza and other acute respiratory viral infections?

- First of all, this is caused by climatic factors - the rise in the incidence occurs in the autumn-winter period, as well as in early spring.

At this time, it gets colder, people are more crowded, the ventilation of the premises worsens, there is no solar insolation - all this creates favorable conditions for the transmission of pathogens.

For example, in the tropics there is no seasonality of SARS.

— Why did the coronavirus become an exception in this regard, because its epidemic waves are not tied to the seasons?

- The fact is that SARS-CoV-2 was a new virus, its spread is characterized by off-season.

Viruses that can cause such pandemics are still unusual for the human body, so special conditions are not needed for the development of such an infection, people easily become infected and fall ill.

The same will be observed if a pandemic version of influenza appears - the incidence will not be tied to the autumn-winter season.

The experience of previous pandemics shows that during the emergence of a new pandemic pathogen, the principle of seasonality does not work.

Later, as the dominant variant of the virus forms and people adapt to it, the disease becomes seasonal.

- Is it true that in the case of a severe course, the flu causes consequences that are in many ways similar to the consequences of COVID-19 - pneumonia and cytokine storm?

What is the main danger of the flu?

- Yes, the severe course of any respiratory infection is the same.

There are isolated symptoms that allow the doctor to assume which virus caused a particular pathology - the causative agent of influenza, parainfluenza, coronavirus, adenovirus, etc. However, it is possible to determine exactly which pathogen is in question only with the help of laboratory tests.

Approaches to the treatment of respiratory infections are also very similar.

As for the flu, it is dangerous for its complications: pneumonia or, for example, exacerbation of the chronic pathology that the patient already has - from the cardiovascular system, pulmonary system, central nervous system, etc.

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Therefore, we say that people at risk are the first to be vaccinated against influenza and COVID-19 - they often have a severe disease, and long-term health problems are also likely.

The risk group includes people over 60 years old, people with chronic diseases, pregnant women, young children.

For example, older people are known to have a high risk of developing a stroke or myocardial infarction for several weeks after suffering the flu.

- If we talk about the viruses themselves, then the main feature of the flu is its ability to permanently mutate?

- Indeed, a characteristic feature of influenza viruses, which distinguishes it from other causative agents of SARS, is its ability to quickly mutate.

It is for this reason that we cannot yet make a universal influenza vaccine.

- In your opinion, are the epidemiological services of countries ready today for the emergence of a pandemic variant of the flu, similar to the Spanish flu?

Have organizational lessons been learned from the coronavirus pandemic?

“We are constantly preparing for a flu pandemic, we were preparing even before the 2009 flu pandemic.

Both at the WHO level and at the level of national health systems there are adopted plans to combat the spread of infection, guidelines, stocks of medicines - we can talk about a well-functioning system for preparing for an influenza pandemic.

Therefore, in 2009, although an influenza A (H1N1) pandemic was declared, it was nevertheless quickly stopped and did not acquire such grandiose proportions as the previous ones.

— During the coronavirus pandemic, huge resources around the world were thrown into the search for new antiviral drugs and drugs for the consequences of the disease.

Can these developments push the development of anti-influenza therapy?

- Influenza and other acute respiratory viral infections are the main infectious diseases in terms of the number of cases in the world.

Experience in combating COVID-19, including the development of new vaccines and antiviral drugs, is now being applied in the fight against other infectious diseases.

Of greatest interest today is the experience of using monoclonal antibodies for the treatment of infectious diseases.

Now a qualitative leap has been made in this area both in terms of production and in terms of application.

• Influenza virus under the microscope

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• © CAVALLINI JAMES/BSIP/Universal Images Group

- Many people do not go to the doctor for the flu and SARS.

Under what symptoms should this be done to avoid serious consequences?

- The main thing is that a person does not ask for help too late.

Of course, each case of the disease requires a doctor's consultation.

Particular attention should be paid when people from the mentioned risk groups are ill.

Such patients do not need to wait until the disease develops; any respiratory or other infection should immediately cause alertness in them or their environment.

As for people who are not at risk, each case is individual, but with a deterioration in general well-being, shortness of breath, lack of oxygen or other unusual manifestations, you should consult a doctor.