Covid revolutionized the world of viruses, fungi and bacteria: how mad

The coronavirus pandemic has dramatically changed our world. It is still far from complete, but today many scientists are recording a huge number of changes that shape our new reality. First of all, the whole world has entered the era of polydemics (tweendemia, tridemia, or even X-demia): several viruses will determine the incidence at once.

At the same time, if before the arrival of covid, each virus had its own seasonality, now there is no seasonality, which means it is completely incomprehensible when to be vaccinated. SARS-CoV-2 has changed the course of many familiar viruses beyond recognition. Experts discussed what else covid has brought to our lives during the XV Annual All-Russian Congress on Infectious Diseases named after academician V.I. Pokrovsky.

Viruses have come out

The pandemic has affected many aspects of our lives. Yes, and in the nature of viruses there have been dramatic changes. Scientists and doctors are watching with great surprise how everything is mixed up: viruses with previously predictable behavior and well-defined seasonality, as they say, have burst their banks. Associate Professor of the Central Research Institute of Epidemiology of Rospotrebnadzor Elena Melekhina states that with the advent of the pandemic strain that broke the entire planet, we live in a new normality: “Many things have changed, including viruses, fungi and microorganisms. For example, rhinoviruses are asymptomatic in 18% of cases, and even in summer we find influenza B carriers in 3% of people. The post-COVID period makes us remember invisible enemies.”

According to a well-known infectious disease specialist, Academician of the Russian Academy of Sciences, Professor Yuri Lobzin, due to the covid pandemic, the population developed “immune debt” – for a long time we actually did not get sick with anything except the coronavirus. And now viruses are developing new models of coexistence with each other. The flu first completely disappeared. According to the head of the Department of Hospital Therapy No. 2 of the Medical Faculty of Sechenov University, Leonid Dvoretsky, in 2021 only 9 cases of influenza were registered, although before that – 5-6 thousand a year: active vaccination will also have an effect.

As Denis Usenko, a leading researcher at the Clinical Department of Infectious Pathology at the Central Research Institute of Epidemiology, notes, since 2022, the influenza infection has become unusually active: “A fundamentally new trend has appeared – the influenza B virus was detected in our country even in May, which did not happen before at all. Today it is detected along with rhino-, bokovirus, RSV and metapneumovirus. Today, according to the Research Institute of Influenza, in fact, in a third of the country’s cities, the thresholds for influenza B have been increased by 20%, and this is, consider, the beginning of April. But COVID-19 does not lose its position, occupying about 15% in the SARS structure. It is surprisingly stable, regardless of seasonality.”

As Academician Yuri Lobzin says, there has been a dramatic shift in the structure of traditional seasonal viruses: “COVID-19 has changed the epidemiology of acute respiratory infections. New highly pathogenic variants of viruses have emerged. We began to identify many patients with simultaneous infection with different viruses. The flu season is now running longer. Many viruses have lost their seasonality during the pandemic. For example, out-of-season outbreaks of RSV have appeared, it was previously unthinkable to see such patients in June or July. Metapneumovirus used to be in winter and early spring, but now it is year-round. Same story with parainfluenza and rhinovirus. The leaders among respiratory viruses around the world are looming – these are rhinovirus, metapneumovirus and coronavirus. Well, future pandemics are likely to be caused by RNA viruses.”

Another threat that has appeared in the world after (because of?) the pandemic is the “updated” streptococcal infection. Today, a new genovariant of group A streptococcal infection and scarlet fever (GABHS infection) with high invasiveness and altered sensitivity to antibiotics is circulating. This option caused an increase in morbidity and mortality in Europe and England. Over 300 people died from it in the UK alone in 6 months. The chief sanitary doctor of the country, Anna Popova, recently ordered that special emphasis be placed on monitoring this infection.

Fungal diseases behave differently. Doctors say that earlier with manifestations of such fungi as Aspergillus or Candida, they met 2-3 times a year, today – 2-3 times a day. The reason is the mass immunosuppressive therapy that patients were given for covid, and this created excellent conditions for the selection of mushrooms. Prolonged mechanical ventilation allows them to develop in hospitals, and today doctors call the contamination of these microorganisms in hospitals “creepy.” In children, candidiasis began to be detected en masse, which is associated with the active treatment of tonsillitis, which has become very numerous against the backdrop of the pandemic. And yet – after mixed infections in children, markers of myocarditis, vasculitis and ECG changes began to be detected more often.

Children get sick more often

At the beginning of the pandemic, children were rarely and easily ill with covid. Scientists noted that they were protected by an immature receptor system. However, everything has changed – and today it is children who have become the bulk of patients with COVID-19.

According to the chief freelance specialist in infectious diseases in children of St. Petersburg, Elena Dondurei, in 2021, the economic damage in Russia from only 32 viral diseases amounted to more than 800 billion rubles, and respiratory viruses accounted for 93.2% of the damage. After the pandemic, patients are increasingly registering mixed infections (that is, several viral pathogens at once). “In a hospital setting, mixed infection in children is 30-50%,” says Elena Dondurei.

At the same time, a unique epidemiological picture is observed every month. For example, last year there was a lot of talk about tridemia: at the beginning of the year, the incidence was mainly formed by respiratory syncytial virus (RSV), rhinovirus and pandemic coronavirus. Then the rise of influenza began, and the picture of the tridemic changed: the top three were influenza, the “corona” and the rhinovirus. When “Omicron” came, he first forced out all the competitors, then he began to rule the ball in tandem with RSV (didemia), and all other viruses were suppressed by their circulation. “Starting from August 2022, children began to get sick with coronavirus very actively. Along with it, rhinovirus was active. In November, RSV came, then the flu began to rise, then rhinoviruses reappeared – and the coronavirus infection began to rise again. Now influenza B continues to be detected in our country, coronavirus infection remains at the same level – 10% of cases of all acute respiratory viral infections. Covid is gradually being integrated into the structure of respiratory pathology. An unpleasant trend is that after the pandemic, children became more likely to get bacterial pneumonia as a complication of any SARS. In November, we recorded an increase in pneumonia up to 30%. Moreover, other viral pathologies are complicated in small patients with pneumonia many times more often than covid.”

Experts suggest that the reason for this may be a serious decrease in immunity in children who have had SARS-CoV-2. At the same time, several scientific papers have shown an unpleasant trend: children today suffer from severe post-COVID even with asymptomatic or asymptomatic course of coronavirus infection.

Postcovid bunch of infections

…Elena Melekhina and Denis Usenko talk about an unusual patient whose course of illness speaks of many post-pandemic trends. This is a 10-year-old boy who almost never had ARVI and did not take antibiotics. The child was admitted to the hospital with fever, skin rash and dry cough. By the time of hospitalization, he had been ill for 18 days, received antipyretics and cough medicines, and then antibiotics. He was suspected to have measles, herpes type 6, Epstein-Barr virus, reaction to an antibiotic. “We live in a new post-COVID normality, so a lot has changed, including in patients. Due to lockdowns around the world, the timing of vaccination has been violated – and today infections that were previously controlled by vaccines, including measles, have become active. In terms of vaccination coverage against whooping cough and measles, according to WHO, the world today is at the level of the 1990s. The pandemic could affect acquired post-vaccination immunity: people who have had COVID-19 may have reduced immunity after other vaccinations, ”the doctors say.

But back to the unusual patient. Tests revealed that he had influenza B, which the doctors felt was not enough: this influenza virus never lasts so long. Doctors hypothesized that earlier the child could have been ill with covid asymptomatically, which caused an increase in the influenza virus (scientific work on this topic already exists). “Respiratory viruses have changed a lot with the advent of the pandemic, we now live in a world of combined infections, some are already talking about the X-Demia. Viruses in patients coexist with fungi – mycoplasma, pneumococcus, aspergillus, candida. This child was also diagnosed with a fungal infection – mycoplasma. And this can also be a consequence of the postponed covid. And you can add that the post-covid syndrome can occur in different ways, including in the form of an altered sensitivity to a number of drugs. And, perhaps, the boy gave such a reaction in the form of a rash to antibiotics, ”experts continue to argue.

In addition, they add that post-COVID syndrome in children develops regardless of the severity of the disease. And even if the child did not have any symptoms, antibodies and severe post-COVID can be detected in him. By the way, among the manifestations of post-covid syndrome in children, a rash of various etiologies comes first (75% of cases). On the second – frequent SARS. Chinese researchers have shown that in the post-COVID era, up to 15% of respiratory diseases in children occur simultaneously with mycoplasma infections, which cause pneumonia in 70% of cases, but are asymptomatic in 10%. But in the latter case, the disease will constantly return and cause a cough.

Bingo: IgG antibodies to SARS-CoV-2 were found in the child’s blood, confirming that he still had coronavirus. Well, since it happened, it is known that in children after covid, the secretion of immunoglobulin A decreases. It is this type of immunoglobulin that is responsible in the body for preventing the development of bacterial superinfections: it cannot be ruled out that this is exactly what happened to the child.

And yet today, many experts have reconsidered their views on vaccinating children against SARS-CoV-2. “Today, 267 sublines of Omicron have been identified, the effectiveness of the vaccine against each line must be confirmed. Plus, there are many who have been ill who have antibodies. Are the antibodies produced during vaccination that protect against current coronaviruses? We need careful approaches to vaccinating children against SARS-CoV-2,” says Denis Usenko.

What new challenges will the pandemic open up for us? So far, no one knows. But there is no doubt that the coronavirus will continue to change the world.