Experts are struggling for explanations: Why are children currently getting so sick?

While pediatricians and emergency physicians at children's wards are sounding the alarm about overcrowding, parents are worried.

Experts are struggling for explanations: Why are children currently getting so sick?

While pediatricians and emergency physicians at children's wards are sounding the alarm about overcrowding, parents are worried. The reason: More and more children are sick and have to stay at home, some even need to be treated in hospital. So far we can only speculate about the causes.

Concerned parents, overcrowded waiting rooms: as the temperature drops, so does the number of infections. But this year there seems to be a particularly large number of cases and particularly severe courses early on. While paediatricians hardly manage to treat all children, emergency physicians from children's wards sound the alarm because of overcrowding. But what is different this year than usual? Specialists find a number of explanations.

For paediatricians, neither the pandemic nor the corona measures taken are the cause of the current sometimes dramatic situations in the clinics. "Politics are responsible for the fact that children's lives are in danger at the moment," says Jakob Maske, spokesman for the professional association of paediatricians. "Children die because we can no longer take care of them," explains Michael Sasse, senior physician in pediatric intensive care at the Hannover Medical School. He is certain that the lifted corona measures have led to the current situation. "Now three years of children will go through these infections because they run around without a face mask," said Sasse. That overwhelms the clinics in a "total way".

The general practitioner Peter Schleicher from Munich has a slightly different point of view. For him, the mask requirement that was enacted during the corona pandemic is responsible for the large number of diseases in children. The mask was a "fatal mistake of politics", the doctor is quoted as saying by the "Bild-Zeitung". According to him, children need 14 to 16 infections a year to train their immune system. But this explanation is too simplistic for a number of colleagues.

Corona measures, such as social distancing and wearing masks, have certainly led to people becoming less likely to be infected with seasonal respiratory pathogens in the past two years. But the fact that these measures have had a lasting effect on or even damaged the immune system in children is something that the virologist Isabella Eckerle does not want to leave unanswered: She writes on Twitter: "There is no 'infection account' that you have to work through so that you end up of the year is zero. If you get infected less than average, then you don't have to catch up later. You're just less sick."

Friedrich Reichert sees it similarly. The senior physician of the pediatric interdisciplinary emergency room at the Stuttgart Clinic says: "The immune system works great, even after the measures - there is no evidence that the absence of infections would somehow weaken the immune system," Reichert is quoted as saying according to the Tagesschau.

Nevertheless, the question arises as to why the current wave of infections is hitting children in particular so drastically. "The truth is, we don't know," says Berit Lange of the magazine "Spektrum". For the epidemiologist, who is head of clinical epidemiology at the Helmholtz Center for Infection Research, the current wave of colds in children is no surprise, but why the infections are pushing clinics to their limits is still a mystery.

Many of the children who are currently being treated in hospitals for respiratory infections have contracted the so-called respiratory syncytial virus, or RSV for short. However, this is not due to the fact that the viruses have new properties through mutation and now cause particularly drastic symptoms or are easier to transmit, according to Lange. "In the case of RSV, it is not the case that new variants have appeared here, but that a significant proportion of the children did not go through the first infection with the virus at the normal time," explains the epidemiologist. Pediatricians therefore have to treat a significant proportion of small patients between the ages of zero and four years who are currently probably infected with RS viruses for the first time. The infections that were missing due to the corona measures are now apparently being made up for. There may have been a similar effect last year.

Usually, the first infections with RS viruses occur mainly in the first two years of life in humans. They are the most common triggers for acute respiratory infections in infants and young children. By the end of the second year of life, almost all children have usually had an infection with the RS viruses, half of them have even survived a second RSV infection.

There is a suspicion that a number of the children who are currently ill are just becoming infected with RS viruses for the first time, although they are well over two years old. This often happens in kindergarten. It is already known from the past that the first RSV infections in infants and young children are more severe than those that follow. However, it is not yet clear whether there is a connection between the age of the initial infection and the degree of severity.

Another explanation for the increase in more severe courses after RSV infections is also associated with the corona measures. In principle, pregnant women who become infected with RS viruses in the last few weeks before the birth of their child can transfer antibodies to the unborn child. This gives them partial immunity. This cannot later prevent the disease caused by RS viruses, but it can prevent severe courses.

Due to the corona measures, fewer pregnant women were infected with RS viruses and therefore did not transfer any immune protection to their unborn children. "Of course, that's a wild hypothesis, one has to say. Nobody knows exactly how nest protection against respiratory viruses is," says Johannes Hübner, deputy clinic director and pediatric infectiologist at Dr. from the Hauner Children's Hospital in Munich, according to "Spektrum". The role of the effect is unclear, but it is at least plausible. "That's one of the reasons why we want to vaccinate pregnant women against influenza: so that they can transmit influenza antibodies to their children."

In fact, pediatricians are concerned not only about the RS virus, but also about the influenza pathogen. Because this seems to play a role much earlier than usual this season. "This year, both RSV and influenza started at the same time," explains Reichert. If the flu wave is high, there will be acute supply problems.

It is also conceivable for some paediatricians that previous infections with Sars-CoV-2 are leading to the current high level of sick leave and the numerous hospitalizations of children. Because the virus itself, regardless of whether the infection has progressed with or without symptoms, could have a weakening effect on the immune system. The situation is very similar with the causative agents of measles. It is already known that they weaken the immune system. Those infected still have to contend with secondary diseases weeks after contracting measles.

Whether Sars-CoV-2 actually weakens the immune system of children can hardly be found out with scientific studies. The problem: There are only a few children who have not yet had a corona infection - and that would mean that the control group necessary for scientific studies would be missing.