But provisionality in processing knowledge is the basic attitude of serious science. We have been able to observe this process live, as it were, in the case of vaccines. The original assumption that a vaccine would also cause full immunity had to be corrected: vaccinated people can still fall ill and infect others. However, they hardly ever end up in an intensive care unit and it is only in exception cases that they have to be intubated and put on a ventilator.

The question is: What has changed with Omicron? Do infected patients still require intensive care, or do they "only" end up in the isolation ward in the worst case? Will Omicron become known as the "mild course"?

Many people may be underestimating this apparent harmlessness - especially those who have not yet had Covid. Because quite a few people who are currently infected with Omicron, or who have been, are completely shattered. They complain of headaches and aching limbs, scratchy throats, severe rhinitis, a nagging cough and hoarseness; sometimes they have a high fever for days. Above all, they feel a lethargy that makes them ask sarcastically, "This is supposed to be a mild course?" On the other hand, there are people who feel nothing at all or only have a little cold. It may also be that they have only caught a few viruses. Several studies are currently underway to find out exactly who gets sick and when.

In fact, infectious medicine specialists have erected a wall that separates mild and not mild courses: pneumonia. This makes sense. Unless new findings come to light, Omicron has the characteristic of settling and multiplying mainly in the upper respiratory tract. It hardly ever reaches the lungs. "In general, internal organs are only rarely affected by omicron, which was completely different with earlier variants such as Delta." says Huan N. Nguyen, chief internist at the Municipal Clinics in Mönchengladbach.

For those affected, this means: what they perceive as severe is considered a "mild course" by doctors. On the other side of the wall it would look different, because here typical medications such as dexamethasone and oxygen therapy - in whatever form - are used. Only patients who fulfil at least one of the criteria unvaccinated, with risk factors, or with underlying health issues are likely to end up here.

People with coronary heart disease must be careful not to become infected with Omicron. The Coronavirus can also cause the formation of blood clots. If a patient has sudden heart pains that indicate a heart attack, an existing Omicron infection can significantly increase the risk of serious illness. Likewise, people with immune deficiency, for example after an organ transplant, must avoid infection just as much as cancer patients. It is not uncommon for the viral load to remain so high for weeks or even months that therapy has to be interrupted.

Omicron has not been the leading variant for too long, so no clear epidemiological data can yet be given on who develops long Covid or post Covid after being infected. These terms are often mixed up and even interchanged. Long Covid is the general term for all symptoms that persist or reappear for more than four weeks after infection and the acute phase. The first phase after that is called subacute (four to twelve weeks after infection). Everything after that falls under post Covid.

However, vaccination is also having a positive effect here with Omicron, says Nguyen. "We don't see long Covid as often now, because many more people have been vaccinated than a year ago. However, as far as Omicron is concerned, there is still no reliable data on long Covid in the unvaccinated.

It is impossible to predict what the consequences of a Coronavirus infection will be in the future.

The issue of long Covid continues to exist anyway, because new data show that the long-distance effect of an infection with Corona virus, no matter which variant, can also manifest itself in other organ systems. Scientists led by Wolfgang Rathmann of the German Diabetes Centre in Düsseldorf have investigated whether type 2 diabetes can occur as a result of a Covid infection. They analysed the health status of more than 70,000 patients undergoing treatment in German doctors’ offices and sorted them into two groups. While the first group had already been infected with Coronavirus, the second had recently suffered another respiratory virus infection.

It turned out that significantly more previously healthy people had type 2 diabetes after a Coronavirus infection than after another type of cold. The risk was 28 percent higher. What was striking in the sub-analysis was that the Coronavirus-infected people studied had relatively mild Covid-19 symptoms. This means that one can develop post-Covid symptoms even if the initial encounter with the Coronavirus was mild. It remains to be seen whether late-onset diabetes can also occur after an Omicron infection.

However, even Omicron patients should take it easy for a while after recovering, for example, when doing sports. There are well documented cases of athletes who wanted to get back into the swing of things too quickly after an infection who suddenly had myocarditis (inflammation of the heart muscle). This can also happen with Omicron.

Another study, this time from the University Hospital in Hamburg-Eppendorf (UKE), also produced long-term data, concerning the liver. It has long been known that Covid patients sometimes have abnormal liver values, even if they were previously healthy. After autopsies on 45 people who died of Covid, pathologists found that in two thirds of them the pathogen could be detected not only in the heart, lungs and kidneys, but also in the liver, in some cases even still in an active state.

The Hamburg experts consider it conceivable - they put forward this hypothesis in their study - that a Sars-CoV-2 infection could significantly alter the cell programmes in the liver and thus have a similar effect on metabolism as hepatitis. "These results once again underline how diverse the potential damage mechanisms are in Covid-19," study leader Tobias Huber, director of the Medical Clinic and Polyclinic at the University Hospital Eppendorf, told Der Spiegel. It is possible that in the coming years and decades there will be an increase in secondary Covid-19 diseases in organs such as the liver and kidneys.

Of course, this does not have to happen in a dramatic form. But in any case, doctors will know in future what to think about when their patients' blood count changes are questionable or when their initial medical history is conspicuous: What was that about Coronavirus?

Original article: Wolfram Goertz

Translation: Jean Lennox