Omicron is commonly considered a mild variant of the coronavirus. Several studies attest that the variant has a milder course of the disease than Delta. But “mild is something else…”, tweeted Christian Karagiannidis, scientific head of the DIVI intensive care register and head of the ECMO center of the Cologne-Merheim Lung Clinic, last Friday. What happened?
In his tweet, Karagiannidis refers to the rapidly increasing number of hospitalizations in the USA. There – where the omicron variant has been predominant since Christmas – new highs in corona-related hospital admissions are currently being measured. The US clinics currently have more than 150,000 corona patients.
“If a patient is in the hospital, then it’s no longer a mild course,” says Karagiannidis to the daily mirror and tries to define the World Health Organization. This is: A mild course is when an infected person has no symptoms or is symptomatic, but can still be cared for independently or with the help of an outpatient.
But what does “mild” even mean?
According to the WHO, if a person suffering from Covid-19 is admitted to a hospital, their status deteriorates – to moderate. According to the definition, a mild course is present up to the point in time when a person shows symptoms that are so severe that they have to be admitted to the hospital.
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The Robert Koch Institute (RKI) has adapted the WHO definition for its own clinical classifications:
- Asymptomatic infection: no symptoms
- Mild/moderate illness: a variety of symptoms with no signs of severe illness (e.g.: cold symptoms, changes in taste/smell, diarrhoea)
- Serious illness: from severe pneumonia
- Critical Illness: Patient requires ventilator or other type of organ support
But the distinction between hospitalized and non-hospitalized Covid sufferers is by no means that easy, explains Sebastian Dolff, senior physician at the clinic for infectiology at Essen University Medicine, to the Tagesspiegel. In German hospitals there are definitely corona patients with a mild course.
In some cases, a corona infection is only detected in the hospital because the person to be treated was admitted for another condition. But people at risk are also admitted to clinics despite a mild course in order to better monitor the course of the disease. “I therefore prefer to speak of uncomplicated, complicated and critical processes,” says Dolff.
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In the eyes of the outside world, “the use of the terms ‘mild and milder course’ has gotten completely mixed up,” explains Karagiannidis, scientific director of the DIVI intensive care register.
The study data so far show that a disease with the omicron variant is milder, but only compared to the Delta variant. This is the result of studies from South Africa – where the mutant was first detected – and the USA, among others.
Omicron variant milder than Delta
South African scientists found that people who had the omicron variant were 80 percent less likely to be hospitalized.
As a comparison, the experts used data from previous variants. According to the study, people who were hospitalized with Omikron developed milder disease courses in 70 percent of the cases than with Delta.
A study by the University of California, Berkeley, shows similar results: hospital admissions are 50% lower with Omicron than with Delta. The duration of hospitalization is also reduced by 70 percent with Omikron.
The risk of dying from the disease is reduced by 91 percent at Omikron. Both studies have not yet been independently reviewed. Data from the British health authority UKHSA shows a comparable trend.
Lauterbach: Different population structure in Germany
But the numbers could develop differently in Germany: Health Minister Karl Lauterbach recently said in an interview with the news portal “The Pioneer” that the study results cannot be applied one-to-one to Germany.
In contrast to South Africa, the population in this country is much older, according to the SPD politician. Great Britain, on the other hand, has the advantage that many risk groups there – including older people – have already been boosted.
In Germany, the proportion of people who have received a booster vaccination is lower than in the UK. The SPD politician sums up that the boosters started too late.
According to Lauterbach, the danger is that the omicron variant, which first appeared primarily in younger people in Germany, is now increasingly spreading among the older and unvaccinated sections of the population. It is not yet clear whether these groups will also have a milder course than Delta.
“As far as the omicron wave is concerned, I see a crucial difference compared to the delta wave,” explains Essen senior physician Sebastian Dolff. In the last wave, many patients had not yet been boosted. “A triple vaccination protection protects against severe courses.”
Increase in therapy options leads to milder courses
But there is still a decisive advantage compared to fighting the first corona waves, explains Daniel Drömann, medical director of the clinic for pulmonary medicine at the University Hospital Schleswig-Holstein, when asked by the Tagesspiegel: It is now possible to treat risk groups with tablets or a one-time infusion treated with neutralizing antibodies on an outpatient basis. In this way, capacities could be kept free for difficult courses.
However, the new possibilities in Covid-19 treatment are also shifting external perceptions: Without outpatient therapy, more people would possibly be admitted to hospital and their disease status would shift from mild to moderate according to the WHO definition.
“At the moment, the number of patients in our intensive care units is stagnating,” says Drömann. There has also been no increase in patients in the normal wards. The reason he gives is that the omicron wave in Lübeck and throughout Schleswig-Holstein first reached the younger population group.
There is confusion surrounding the term “mild”
“We can’t yet say how mild or severe the omicron variant will ultimately be for us,” explains Drömann. “We’ll only know more after the fact.” But: “No doctor will carelessly speak of a ‘mild course’ for Omikron.”
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“A mild course always sounds a bit too harmless for all of us,” says DIVI expert Karagiannidis. In fact, he is not at all. The large number of people who did not go to the hospital despite severe symptoms and were therefore not recorded as such were completely ignored.
Various interlocutors have also reported on this research to the daily mirror of treated people and acquaintances who are now suffering from long-term consequences even without hospitalization.
A mild course of Covid-19 does not protect against long-term damage
“I’ve seen enough patients whose lung CT showed clear changes even months after surviving Covid disease,” says the scientific director of the DIVI intensive care register and the ECMO center of the Cologne-Merheim lung clinic. That’s why the term “mild course” is so difficult to define.
Several studies confirm Karagiannidis in his observation of long-term consequences of supposedly mild courses. A study from Japan found serious brain damage even in patients who were not hospitalized. An Oxford study reports memory loss and a reduced attention span – even six to nine months after a mild course of Covid 19.
More on the subject on Tagesspiegel Plus:
Researchers at the Eppendorf University Hospital have examined people who have only gone through a comparatively mild course of Covid 19. None of the study participants received intensive care treatment and only seven percent of the study participants were hospitalized.
Nevertheless, according to the study, their lung volume was reduced by around three percent compared to a comparison group of non-infected people. The heart also pumped one to two percent less blood. This could indicate damage to the heart, lungs and kidneys.
“The knowledge that even a mild course of the disease can lead to damage to various organs in the medium term is of the utmost importance, especially with regard to the current omicron variant, which mostly seems to be associated with milder symptoms,” write the authors of the study.
According to a study by the Mainz University Medical Center, around 40 percent of all people infected with corona suffer from long-term consequences, also known as long-Covid. Women are more affected than men.
