Over the past few days, several items have appeared about long covid. New research could provide breakthroughs in our understanding of the disease. Perhaps even new treatments are emerging. But is that really what the cited studies prove? Wietse Wiels, neurologist and chairman of SKEPP, calls for caution.
I have already asked questions in the past about communication about long covid. Yet I like to repeat again and again: I am not saying that there is nothing wrong with lung covid patients or that they are purely psychologically ill. That long covid “doesn’t exist” is a meaningless statement that I never made.
It is my opinion, however, that the incidence of the disease is greatly overestimated. Many patients are indistinguishable from fellow citizens with chronic complaints that also existed before the pandemic. In addition, I am concerned that overly scary reporting can be dangerous, and that overly simplistic biological explanatory models create false hope.
The recent press releases are based on two studies. The first comes from the Netherlands, the second from the US
First study: good or bad news?
This population study from the Netherlands is, as we are used to from our northern neighbors, impressive. They surveyed nearly 80,000 participants. An advantage over previous epidemiological studies is that these people were already monitored before the pandemic. In addition, much more extensive statistical ‘correction’ was carried out for other diseases. In those two areas, other publications showed serious shortcomings.
It is striking that the percentages of post-covid (the term they use) complaints in this study are a lot lower than in previous reports. This is probably due to the methodological shortcomings I mentioned. According to most news reports, this study would show that “one in eight” people develop lung COVID after infection. But where does that figure come from?
Some numbers
With apologies for the dry numbers, here are some results. The percentage of participants with at least one moderate or severe disturbing symptom several months after infection was 40.7% after covid infection and 29.3% without covid infection. By the way, the most common symptoms are back pain and muscle pain (13.5% and 10.8% after COVID, 8.7% and 9.5% without) – although these symptoms were not surveyed before the pandemic. General fatigue increased after covid infection in 4.9% of the participants and 2.1% of the non-infected group.
The researchers then looked at a group of “core symptoms” of lung covid. They defined it themselves on the basis of frequency. These are loss of smell, difficulty and pain when breathing, chest pain, lump in the throat, heavy and tingling limbs, aching muscles, fatigue, and feeling hot and cold at the same time. In 21.4% of participants who had covid-19 (a total of 381 people), at least one of those symptoms increased to moderate intensity after infection compared to before. In other words: someone was already tired, but it got worse and/or disturbing. Or someone smelled everything fine, but now continues to struggle with moderately serious loss of smell. And so on. Among civilians who did not become infected, 8.7% (that is 361 people) became ‘sicker’ according to this narrow definition. The difference between those two numbers is… 12.7%. So about one in eight. Hence the titles.
Apples and pears?
About one in eight people living through Covid-19 will have at least one moderately severe symptom from the above list three months after being infected, more than we would expect in the general population.
That tells us that SARS-CoV-2 is indeed a dirty beast. It gets into the clothes and can increase complaints. A symptom such as loss of smell can drag on for a long time and have a major impact on quality of life. Certain symptoms already present – fatigue, back pain, … – can be seriously knocked out of balance by the virus. It is striking that a large number of sensations (crop in the throat, tingling limbs, chest pain, etc.) are symptoms that frequently occur without a structural cause and often go away on their own.
However, the majority of testimonials about Lung COVID are provided by people who are very ill. Not infrequently they are dependent on outside help and unable to work. The introduction of the Dutch study uses the word ‘debilitating’. Patients testify to a long list of symptoms in different organ systems. Several activities have become very difficult or impossible. Sometimes certain patterns return (sometimes called ‘symptom clusters’), but sometimes they don’t. Many remain ill for a long time, including certain victims of the first or second wave in 2020. This disabling disease has little or nothing to do with one or more symptoms becoming moderately severe after three months in 12.7% of the infected.
It is therefore simply incorrect to claim that this study proves that 1 in 8 infections with SARS-CoV-2 is followed by Lung COVID. Or as most people and activists understand long covid: the serious illness from the testimonials. In the meantime, it may well have been done with preaching doom about that wave of hundreds of thousands of disabled compatriots.
Second study: a laboratory is not a waiting room
For the second study, many measurements were performed in different groups of people with and without covid infection and with and without lung covid. Most news items contain a brief mention that the article is a so-called preprint is. That is, the data contained therein was in no way checked by colleagues. Although this so-called ‘peer review’ is certainly not a magical quality filter, one should really not draw conclusions for medical practice from this data. The latter is even literally repeated on the preprint website medrxiv. Unfortunately, that message is often lost by immediately linking a report about specific patients to the findings. That’s not how medical science works.
It is important to realize that the study involved very complex lab analyses. These are hardly ever used in clinical practice, and are not intended for that purpose. For many parameters related to the immune system, no differences were found between the different groups. In fact, patients with lung covid in this study were significantly older and more obese than those from other groups. They also had, for example, 2 to 5 times more often asthma and twice as often irritable bowel syndrome. That too can affect tests.
Cortisol
The most notable and discussed abnormality is that of the cortisol level. On average, this is half as low in lung covid patients as in participants without the condition. I repeat: average! This means that a test on one patient does not allow to be diagnosed as ‘ill’ or ‘not sick’. It is difficult to say what this cortisol measurement ‘means’ in concrete terms. Cortisol has various functions and influences our bones, fat, sugar metabolism, stress, immunity, memory… A manifest excess or deficiency of cortisol is called Cushing’s and Addison’s syndrome, respectively. These are serious, life-threatening conditions. More mild disturbances in cortisol, however, have been observed in a whole list of chronic conditions, often with no clear explanation. It is relevant here that a systematically lowered cortisol was also found in the chronic fatigue syndrome (CFS) in the past.
Partly for this reason, there has been a circuit of alternative doctors for many years who treat their patients with cortisones, sometimes under the guise of ‘adrenal fatigue’ (after all, cortisol is produced by a small gland on top of our kidneys). There is not a shred of scientific evidence for this. On the contrary, many patients ended up in serious medical problems thanks to these doctors. Chronic use of cortisol leads to serious complications. They can be deadly.
Our body is a chain of millions of biochemical processes that seamlessly merge into one another. A deviating value of a certain substance does not always mean that the person literally has ‘too much’ or ‘too little’ of it. It can also itself be the result of another process, a normal variant or an indirect effect of health in general (as is increasingly becoming the case for vitamin D, for example). Thousands of studies that tried to treat complex conditions by ‘supplementing’ or ‘blocking’ a substance that was lower or higher than normal in patients have failed. Except in the case of serious nutritional deficiencies, human diseases are rarely so simple. Of course, that doesn’t mean that it should be the case again. But that does mean that one lab study doesn’t allow us to dream of new treatments.
Notwithstanding the warning on preprint websites, there is often long and broad communication in the media about this very specialist finding. It is therefore to be expected that a large group of patients will ask their doctor to check cortisol. This hormone has a striking day-night rhythm and is also influenced by all kinds of things. Normal values vary greatly from person to person. We can therefore assume a large number of false alarms, with all the consequences that entails. Here and there someone might prescribe cortisones, ask about them, or even take matters into their own hands. Dear fellow citizens, dear colleagues: please don’t do this.
And now really
When these kinds of studies come out, you can bet that someone will claim that the disease has now been proven to be ‘real’. Or that she ‘exists’. I’ve always found that a very strange statement.
Does a disease only exist when it can be seen in a blood test? An enormous amount of medical problems do not require ‘technical examinations’. The most common condition on my consultation is headache. Migraine won’t show up on any scanner or blood test. So I don’t believe that my patients have terrible headaches? Of course it is. Every so often, an old (and, by the way, very dubious) study pops up in the media that showed abnormal brain scans in severely neglected children. Now suppose that was not the case. Would we be allowed to abuse children?
It is evident that covid-19 has a long tail for many people. Occasionally, someone who was not acutely ill can get into serious trouble. But there are almost certainly not nearly as many as some enthusiastic journalists and researchers have been claiming for two years.
Complex but unique
That predicted wave of chronic illness doesn’t exist. But we don’t keep it dry either. We are already in the water up to our ankles. Tens of thousands, perhaps hundreds of thousands of compatriots are chronically ill. Just like the lung covid patients from the newspaper are. And they were already there before the events in Wuhan.
Those who do not fit into a strict medical-diagnostic box often do not receive appropriate help. Doctors have to fill out unusual certificates, make fashion diagnoses (eg post-whiplash, chronic mononucleosis,…) or say outright that they can’t help. Being rejected by both physical and psychological care providers: I don’t want to have to experience it. I myself have been obliged several times to send patients abroad for appropriate care. That’s really not serious.
Fortunately, at least we can now offer post-covid patients rehabilitation. That’s for the bright spot in this matter. That we may finally understand that chronically ill people need more than one pill, one note, one therapist. Collaboration is key, tailored to everyone. Please don’t let us focus on the endless stream of alleged breakthroughs from test tubes. That’s going to cost us way too much wasted time, money, and hope. We must not repeat the mistakes of the past. A person is more than a blood test.
Wietse Wiels is a neurologist and chairman van SHIP.