Translartion. Region: Russians Fedetion –
Source: Novosibirsk State University – Novosibirsk State University –
At the popular science marathon “Darwin Week”, a doctor of biological sciences, professor, academician of the Russian Academy of Sciences, head of the laboratory of bionanotechnology, microbiology and virology spoke with a report “Evolution of a set of respiratory infections” Faculty of Natural Sciences of NSU Sergey Netesov.
Evolution of the virus
In Russia, doctors register 28 to 33 million cases of acute respiratory infections every year, but these are official statistics. When seeing a patient, the doctor fills out a statistical form, which is sent for processing to the health authorities, where statistical data is collected. However, not everyone comes to see a therapist, especially if the disease is mild, preferring to endure it “on their feet” or use home remedies to fight the infection. Such patients are not included in these statistics. Therefore, experts assume that the actual number of cases exceeds the official data at least twice.
Acute respiratory infections (ARI) are caused by viruses, bacteria, mycobacteria and mycoplasma. In addition, most likely not all pathogens of ARI in humans have been discovered yet.
Previously, doctors officially diagnosed ARVI without specifying the pathogen and specifically – influenza viruses, and even then the diagnosis was made by the doctor, guided only by the symptoms observed in the patient, and the laboratory diagnostic methods that existed before the 2000s were lengthy, inaccurate and insensitive. More or less reliable test systems for diagnosing influenza viruses based on the polymerase chain reaction PCR method appeared only in the late 90s, and for diagnosing other pathogens – only in the last 5-10 years. The data from a study of the causes of ARVI using the example of one of the counties of the state of Michigan (USA), published in 2002, surprised epidemiologists: influenza was not in the leading positions – its share was only 9%, while ordinary coronaviruses – 14%, rhinovirus – 34%. Unknown infections then accounted for 23%. Later, metapneumoviruses were identified, and their share in the structure of pathogens was about 10% in the category that was previously designated as “unknown infections.” Common coronaviruses, as a rule, have “overtaken” the flu in the share of infected people in the last 20-30 years, but did not pose a serious danger in the form of fatalities – until SARS-CoV-2 appeared, which took millions of lives around the world. At the initial stage of the pandemic, it posed a very serious danger with a mortality rate of up to 6%, but over time, due to the evolution into much less pathogenic variants, it almost equaled the mortality rate of the common flu – 0.1 – 0.2%.
— The high mortality rate from the new coronavirus infection was due to vascular thrombosis, which was classified as a circulatory disease at the initial stages of the pandemic, and a cytokine storm — an overly aggressive immune response of the body to a viral infection. It manifests itself in different ways, depending on the chronic diseases of the infected person — in the form of circulatory diseases, pneumonia, complications of type 1 and type 2 diabetes, and sometimes — digestive organs. In the first six months of the pandemic, there were no reliable diagnostics for SARS-CoV-2 markers. Partly due to this, some cases of death from the new coronavirus infection were attributed to serious chronic diseases that the deceased patients suffered from – diseases of the circulatory system, respiratory system, endocrine system, etc. In addition, unlike most respiratory diseases, people died from the new coronavirus not during the first two weeks of the disease, but within a month or two, so it was believed that the patient’s death was the result of complications rather than an acute viral disease, explained Sergei Netesov.
Over the past few years, the deadly coronavirus has evolved towards changing its antigenic properties and reducing pathogenicity, and is no longer as dangerous in terms of mortality as before. Large-scale vaccination of the population, as well as the immunity formed in those who have recovered, have also had an effect, but in terms of morbidity, this virus still sometimes outpaces the combined influenza viruses A and B, and mortality from it has not been reduced to zero. Last fall, 20-30 people died from Covid every week in Russia. These were mainly elderly people with serious chronic diseases.
Currently, another pathogen of ARVI, the respiratory syncytial virus, is no less dangerous in terms of severe progression and mortality. In certain periods of the 2023-2024 season, its share in the causes of the overall incidence of ARVI was 40%. Scientists and doctors have long found out that it is one of the main causes of severe pneumonia in children and the elderly. Since last year, trials of vaccines against this virus have begun in the European Union and the United States.
In the winter of 2024, rhinovirus was the leading cause of acute respiratory viral infections in Russia. It has unpleasant symptoms because it causes inflammation of the nasal sinuses, but does not pose a danger to humans.
— Only in rare cases is the cause of ARI or ARVI only one pathogen, more often two or three. It often happens that the same patient has one or two ARI pathogens — viral and one — bacterial. In this case, the picture of the disease becomes complex. Viral infections, as a rule, prepare the ground for infection with pathogenic bacteria, — said Sergey Netesov.
Reliable protection
To reduce the risk of severe respiratory viral infections, it is necessary to get vaccinated in a timely manner, and it is advisable for people at increased risk of severe acute respiratory infections to wear medical masks in public places. Sergei Netesov also spoke about the influenza vaccines used in Russia. According to him, it is necessary to choose, if possible, four-component drugs with a share of 15 micrograms of antigens of each subtype of the virus. At the same time, the probability of severe disease is reduced by about 20-30 times. And for unvaccinated people, increased risks of severe acute respiratory infections remain for people with impaired immune systems, diabetics and representatives of other risk groups.
In favor of the effectiveness of masks, Sergei Netesov noted that the mask will not hold a single viral particle, because the size of its pores is too large for this. But viruses in the form of single particles do not fly through the air. They move on microdroplets of fluids in our bodies, released from the body when talking, singing, coughing or sneezing. But these drops have a larger diameter and do not pass through the pores of the mask. And even the most primitive mask holds about 75-80% of such particles, of course, if you cover both your mouth and nose with it. And for infection, the size of the pathogen dose that a person receives is very important. Reducing this dose often leads to zeroing out the infection or getting a very small dose – then the disease does not develop quickly, and the body copes with it much easier.
The flu virus is constantly evolving, and this process is aimed at an important goal for it – to “break through” the previous immunity and infect as many carriers – susceptible people – as possible.
In early 2024, several publications were published in the United States stating that cow milk yields in some regions of the country had begun to decline; later, veterinarians identified the H5N1 subtype of avian influenza in them. The influenza virus of this subtype was first isolated not only from birds, but also from some sick people in 1997 in Singapore, Hong Kong, and Vietnam. The virus also affected people, with a very high mortality rate. The reason was soon revealed: in most cases, it was a rare mutation characteristic of the inhabitants of these countries, in which one of the receptors in their lungs turned out to be similar to a similar receptor in birds. This feature is not typical for residents of other countries. And so in 2024, the virus spread not only among birds, but acquired new mutations and “switched” to cattle and more. Several dead cats that had previously drunk cow’s milk were found near the barns with sick cows. The cause of their death, like the illness of the cows on the farm, was the avian influenza virus. And although humans and animals do not have many common infections, this virus has become one of them. It turned out that at the end of 2023, the virus acquired mutations that allowed it to move from birds to cattle. From the beginning of 2024 to February 2025, 68 cases of infection of dairy and poultry workers were noted worldwide. It seems that this flu virus has not yet spread widely, but careful monitoring of its evolution is necessary.
Race for survival
Scientists believe that the more common this subtype of the virus becomes, the more likely it is to acquire a combination of mutations that will increase the risk of infection in humans. On the other hand, this subtype of flu has been circulating in various bird species and causing rare sporadic infections in humans for more than two decades, but so far there has been no pandemic. This is one of those cases where a pandemic could start next week or never.
— Not only pathogens of viral diseases evolve, but also our immune system. It is a kind of race. Therefore, it is necessary to study not only pathogens, but also the parameters of our immunity. Increase the number and effectiveness of vaccines, increase the volume of vaccination. This really improves the quality of life of the population and increases its duration. At the same time, long-term monitoring studies are needed to study the occurrence of pathogens, their molecular genetic diversity and molecular evolution, including drug resistance. Russia has the necessary instrumental and material-reactive bases, including its own high-tech production of many (but not all) modern vaccines and diagnostics. But their wider implementation in practice is required. It is also necessary to develop new vaccines against a number of viral and bacterial pathogens. Unfortunately, so far the diagnostic algorithms in our compulsory insurance medicine have been worked out to a minimum — primarily due to underfunding. But it is possible to distinguish a bacterial infection from a viral one using a very simple test for the content of procalcitonin and some other markers in the blood, said Sergei Netesov.
The scientist also noted that when fighting a viral disease, regardless of what virus caused it, the patient’s psychological state and the support of loved ones are also important. It is important to be sick in a good mood, then recovery will be faster.
— You should always be positive when you are sick! A person with a bad emotional background is objectively sicker. You need to look to the future with confidence and optimism and tell your body: “Get well.” The human body is a very complex unified system, where all components influence each other. In this case, you need to establish positive feedback between the body and the brain, try to create a good mood for yourself and, of course, follow all the doctor’s recommendations, — said Sergey Netesov.
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