There has been recent evidence of possible long-term damage to Covid 19 disease. What do you have to imagine?
Malcolm Kohler: We are increasingly receiving referrals from patients who still suffer from shortness of breath and cough, even weeks after the acute Covid 19 disease. Most are a so-called post-infectious cough, which is a disease similar to asthma. In some patients, however, there are signs of pulmonary fibrosis, which in severe cases can also be associated with a high-pressure disease in the pulmonary circulation.
Are the diseases all equally serious?
No. The asthma-like diseases are less bad. We already know this from other viral infections. In most cases, the symptoms subside with inhalation therapy within a few weeks.
What about fibrosis and pulmonary hypertension?
The most serious complication is pulmonary fibrosis. If there is scarring in the lungs due to the inflammation caused by the virus, the lungs are less able to absorb oxygen and release carbon dioxide less well. High-pressure diseases in the pulmonary circulation can arise if the patient has severe pulmonary fibrosis with insufficient oxygen in the blood, or they occur as a result of the pulmonary embolism often described in Covid-19.
Can you treat these diseases?
This is actually difficult with pulmonary fibrosis. Medications that affect the immune system can be administered to slow down the excessive inflammatory response caused by the immune system. Fibrosis can progress, and then larger areas of the lung are affected by the scarring. In severe fibrosis, patients need oxygen. In extreme cases, only a lung transplant can help such patients. The pulmonary embolisms often described in Covid-19 are treated with blood thinners and in most cases resolve within months.
Are we talking about long-term treatments?
Yes. Patients with lung fibrosis may need to be treated lifelong.
Are these isolated cases?
Asthma-like symptoms are common. Pulmonary fibrosis rarely occur.
Do infected people who have shown no symptoms also have to worry?
No. No case is known to me in which a patient without symptoms shortly after Covid-19 would suffer from one of the lung diseases mentioned. The serious complications arise after a severe course of the disease. These patients were usually hospitalized. We have also observed asthma-like diseases in patients who did not have a severe Covid 19 course.
How do patients feel that there may be a complication?
They usually suffer from shortness of breath, cough and reduced physical performance.
Do you already know what is responsible for the subsequent illness of Covid-19?
Today we assume that the immune system is overreacting to the virus. You have to imagine it like this: The immune system tries to eliminate the virus under all circumstances, which leads to an enormous inflammation. Without an immune system response, an unchecked spread of the virus would almost certainly lead to death. In certain people, however, the immune system shoots over target. The phenomenon is known from various so-called autoimmune diseases. For example, rheumatism, where the immune system forms antibodies against the body’s own structures and thus leads to inflammation.
Can this overreaction be prevented?
Medications that suppress the immune system – such as cortisone – can help and are also used for autoimmune diseases. With Covid-19, the approach is experimentally investigated in the laboratory.
So you could give patients prophylactic cortisone?
In theory, that would be possible. But you would have to do a clinical study. The thing about the exaggerated immune response is a hypothesis. I am based on the following observation: Patients with asthma or the lung disease COPD are often treated with cortisone to suppress the inflammation in the bronchi caused by the immune system. They are actually considered to be at risk for a severe Covid 19 course. Amazingly, however, they seem to survive Covid-19 disease better than patients with cardiovascular secondary diseases, for example.
The children are said to have few symptoms. Now you read about overreactions and inflammation in different parts of the body. Does that have to worry you?
In fact, it is worrying that children in the United States have also been shown to have Covid-19 vascular inflammation. So far, based on the data in the sparse literature, we have assumed that children will go through a largely harmless course of Covid 19 disease. Vascular inflammation, as has been shown in adult patients, can lead to thrombosis and embolism in various organs. As a result, infarctions of the supplied organ occur. I am in contact with pediatricians and so far I have no knowledge of cases such as those described in the USA.
There are long-term consequences for Sars and Mers diseases, which were also triggered by coronaviruses. What is the difference to Covid-19?
At Sars and Mers we speak of a few hundred or a thousand cases. Covid-19 has millions. Current reports indicate that long-term damage to the lungs in relation to the number of infected people will occur approximately as often as in Sars and Mers. So there will be quite a few people with complications.
What is currently the focus of research into long-term damage?
There are currently very few studies on the long-term course of Covid 19 disease. The Clinic for Pneumology at the University Hospital Zurich is currently starting a study. Patients who were hospitalized for Covid-19 will be monitored over a longer period of time. How are you today? How did you recover from the illness? Was there lung or vascular damage in the long term?
Do you think enough is being done about the long-term health effects of Covid-19?
Most research projects focus on the acute phase of the disease. At first glance, what happens to the patient in the long term seems to be less interesting. General practitioners, in particular, are then confronted with the consequential damage because they look after the patients over the long term. In addition, people are talking primarily about the economic and not the health consequences of the pandemic. But it will affect quite a few people.
At what point did you really survive Covid 19 disease?
There have been known courses where patients have been feeling better for a week, and then they have suddenly become breathless and become seriously ill. If someone has no symptoms for two weeks, the infection appears to be over.