Why are we constantly ill?

Not again! A rattling cough sounds from the children's room. The one from the previous cold had barely disappeared. It had persisted for weeks. It feels like a scratchy throat, runny nose and cough are our constant companions during the winter months. From the children, but also from us parents.

I hear from adults around me who have hardly ever been ill, but who are now spending long periods in bed. Of many cases of pneumonia. Of coughs that only go away with a cortisone spray. I have the impression that we've been sick more often and more persistently since the Covid pandemic. But is that really true?

The protective measures taken as a result of the pandemic have interrupted the transmission of viruses and bacteria.

Christoph Berger, infectiologist

Time to ask the experts. And indeed, they confirm this impression. It is a so-called rebound or catch-up effect. «By taking protective measures such as wearing masks, social distancing and lockdowns, we have interrupted the transmission of virtually all viruses and bacteria that cause respiratory diseases,» explains Christoph Berger, Head of the Department of Infectious Diseases and Hospital Hygiene at the University Children's Hospital Zurich.

In the winter of 2020/2021, for example, there was no flu epidemic. Since spring 2022, the pathogens have gradually returned. «Because we were no longer infected with these viruses and bacteria during the pandemic, we are less immune to them. As a result, we are now falling ill more often and sometimes more severely.»

Immunity has been lost

Nicole Ritz, Head of Paediatric Infectiology at the Children's Hospital of Central Switzerland in Lucerne, explains: «You can think of the immune system as a memory. If it hasn't had contact with certain pathogens for a long time, it no longer knows how to fight them.» Christoph Berger compares the situation to the swinging of a pendulum: «During the pandemic, infections were almost at zero and since then they have been swinging upwards.»

Have we at least already reached the peak? «All known pathogens have now returned, so we can assume that the situation will soon normalise,» says Christoph Berger. After the protective measures were lifted in spring 2022, the respiratory syncytial virus (RS virus) returned. While it normally only causes a cold in healthy children and adults, babies and toddlers under the age of two can develop bronchitis or pneumonia. As a result, children's hospitals were full of young patients in summer and autumn 2022 - not in winter as is usually the case.

Since Covid-19, we have a sensitised perception of being ill.

Nicole Ritz, paediatrician

Respiratory diseases usually occur more frequently in the cold season. The pandemic has disrupted this pattern. Silvio Brugger, Senior Consultant at the Clinic for Infectious Diseases and Hospital Hygiene at the University Hospital Zurich, confirms this: «The way and speed at which the pathogens return varies greatly. This also depends on how easily they can be transmitted.»

A strong wave of whooping cough

At the end of 2022, influenza viruses returned and caused a major flu epidemic. Other viruses and bacteria also gradually returned: group A streptococci, which cause scarlet fever, pneumococci and the more harmless cold viruses. At the beginning of 2024, cases of whooping cough increased. «We see a wave of whooping cough every five years, but last year was particularly strong,» says Christoph Berger.

Whooping cough is particularly dangerous for infants under the age of two and especially for babies under six months. «That's why our main goal is to achieve a high immunisation rate among babies and toddlers,» he explains. As the vaccination can be given from two months of age, it is important to protect the most vulnerable newborns in the first three months. For this reason, parents should be vaccinated before the birth.

For everyone else: «If you have acute cold symptoms, don't visit a baby or wear a mask.» This is because children who have been vaccinated usually do not develop an infection or only a mild cold and cough after coming into contact with the whooping cough bacterium.

Shortly after whooping cough, mycoplasma returned in the summer of 2024. These have caused pneumonia, particularly in children. Paediatrician Stefan Roth in Köniz BE has noticed this in his daily work: «In our practice, we've recently been seeing children who are much more frequently and seriously ill. Mycoplasma is also contributing to this. Older children and adolescents are also increasingly affected.»

Discuss the situation with a sense of proportion

In addition to the catch-up effect, Nicole Ritz sees another reason for the feeling that we are more ill: «The pandemic has shaped us. Since then, we have become more sensitised to being ill.» We now attach more importance to a scratchy throat or a cough that we hardly noticed before. Some people worry about whether they could infect someone else.

Stefan Roth advocates discussing the situation with a sense of proportion. For example, if the children are ill and the grandparents are due to visit: «For many grandparents, it's more important to see the family and they accept a certain risk.» However, the basic rule is: «If you're ill, stay at home.»

Good bacteria kill off bad bacteria

So far, so clear. But one question remains: Has the coronavirus perhaps triggered something in our body, perhaps weakened it? There are media reports that suggest so.

Here, too, the experts interviewed agree: yes in the short term, but no in the long term according to current findings. Nicole Ritz explains: «During and after many viral infections, we are more susceptible to further infections for some time, for example because the nasal mucosa is partially destroyed.»

This is usually the entry point for respiratory tract infections. Therefore, even after infection with basically harmless cold viruses, a so-called superinfection by bacteria can occur, which then cause severe symptoms of illness and require antibiotic treatment, as infectiologist Silvio Brugger explains. «How long we are more susceptible after a viral infection has so far been poorly investigated. We are currently researching this.» Initial indications suggest that it depends on the individual colonisation of the nasal mucosa by good bacteria.

Sick children need two things above all: time and attention.

Stefan Roth, paediatrician

Good bacteria in the nose? Yes, indeed. Just like in the gut, everyone has good and pathogenic bacteria in their nasal microbiome. «The good bacteria can kill or re-educate the pathogenic ones so that they become harmless,» explains Silvio Brugger.

So do people who have a lot of the good bacteria get sick less? «You can't say that across the board. But there is evidence that children who have a lot of the good bacteria are less likely to suffer from middle ear infections and adults are less likely to get pneumonia caused by pneumococci.»

Unfortunately, there is nothing that can be done to promote the growth of good bacteria. «But we are researching whether we can treat bacterial infections with nasal sprays that contain the good bacteria.» To come back to the initial question: It seems that the nasal mucosa of people who have previously had a lot of good bacteria recovers more quickly from Covid and other viral diseases. This means they are less susceptible to further infections for longer.

Vitamin supplements are not necessary

That's all well and good, but is there anything we can do to avoid catching every cold? Here, too, the experts agree: don't smoke, get enough and regular sleep, eat a balanced diet and get enough exercise in the fresh air. Vitamin preparations or dietary supplements are not necessary. «They have developed into a good business for the manufacturing companies,» says paediatrician Nicole Ritz. Nevertheless, she qualifies: «Anyone who is convinced that this or that is good for them should take it. Conviction helps you stay healthy.»

And what if the parents or children have caught it? «Illnesses must be taken seriously,» says Nicole Ritz, but also appeals for patience: «Sometimes you just have to wait and drink tea.» GP Stefan Roth says: «Anyone who likes to use home remedies such as onion or vinegar compresses should definitely do so.» The fever should be brought down if it helps the child's well-being. Children whose general condition is poor and who are not drinking should be taken to the doctor's surgery. «Otherwise, sick children need two things above all: time and attention.»