Immunity, unreported, test accuracy: physicians disentangle Corona-facts-confusion

All Healed are immune to Corona? How accurate are the Tests? And how high the dark figure. Michael Hölscher aims to provide answers to these questions. He is leading a study with 3000 participants in Munich. The research is of the head of the tropical Institute of the Ludwig-Maximilian-University in the beginning. However, he explained in an Interview with “time”, what his research turns out.


Many people ask the question, whether the disease, according to a weathered Corona-immune to the Virus – and for how long. "We don’t know sicher&quot up today;, Hölscher, at the tropical Institute for infectious and tropical medicine explains. The body is a concern for an immune response against the Virus. Whether this protects against re-infection and whether the Convalescent is not really contagious, is still uncertain.

Viruses are very different, explains Hölscher in the "Zeit". Who had the measles once, was probably his entire life to immune. The HI-Virus, however, we develop no immunity. And in the case of the flu and other virus the antibodies appear to be only one to one and a half years.

Hölscher hopes that Corona even more years of protection. And the fact that a recurrence of disease after the end of the immunity course similar to other viruses much easier than the first Time. He says the "Zeit" however, it is obvious: "At the present time I would not advise following a positive antibody test say to herself: I can get the thing ever again, and I can throw myself unrestrained in the social life."

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Dark figure

Currently, the number of Infected in Germany stands at more than 120,000. However, these are only the positively tested. Many people have no symptoms and are not tested at all, or notice the disease not even. A man Corona comes: in a household, are not tested with the other at all. This leads to a high number of unreported cases of Corona cases.

But how high is this dark figure really is? Some experts go from 10 to 20 Times as many infections. Hoelscher says the "Zeit": "I believe that a maximum of two and a half to five times as many people have been infected, as we know, by the current Tests." He thinks the dark figure is low because at the beginning of the epidemic in Germany, very many people have test.

But now less people will feel symptoms, because of the wave of Flu and Cold season are over. In addition, many people remain for a long time at home, and contagion is unlikely. Therefore, would be significantly less citizen test – and, consequently, the number of unreported cases likely to increase, so Hölscher.

Hölscher and his Team accompany in a cohort study over a longer period of 3000 is representative of households in Munich with a total of 4500 people. 12 months, the researchers will visit your subjects again and again. The participants will be tested on Covid-19. In addition, you will be asked about your behavior during the original restrictions. Thus, the scientists hope, among other things, knowledge about the actual spread of the Virus, the immunity of Patients, the course of the disease in different groups. Hölscher stressed that his study will be one of many in the world to gain a better picture of the Coronavirus.

Herd immunity

Experts believe that there are two Ends of the epidemic in Germany. Either it will be found a vaccine that is widely used. Or it is achieved herd immunity. If 60 to 70 percent of the people would be immune to Corona, could be stopped the spread. But how far the stove has advanced immunity to date.

Even taking into account the number of unreported cases is Hölscher little optimistic on this point: "In Germany, we currently have a maximum at a prevalence of one-half to one percent of the population liegen", the physician says in the "Zeit"-Interview. Many would wish that we would be at ten percent. "I don’t think so." Because the Virus was not yet so widespread, wages are also not unique to the Germany Test, the progression of herd immunity to determine, so Hölscher. 

Reported corona virus cases in Germany (click on your state)


Test accuracy Covid-19-patients

Accepted the research finds out that convalescent Covid-19-patients are all immune to the Virus. Then it would be a way to send these people back into the social life. But how accurate are the Tests at all, the Corona diagnose – the so-called test specificity? "If you test 100 people who have never had contact to the Sars-CoV had 2 Virus, should all of the results negative anzeigen", Hoelscher explains. "This is not a Test."

The current Corona Tests were in 1 of 10 cases (bad Tests), or 1 of 50 cases (good Tests) is wrong. You would rely on a Test, then it could be that people are declared to be immune that the disease had never. The other way around also, of course, people could be held to be non-infected, who have made the Virus a long time ago, and antibodies.

To develop, therefore, currently a combined test procedure to increase the test accuracy significantly. Time horizon: "Four Wochen", Hölscher of the &quot says;Zeit".

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Easing the Corona measures

Despite all these findings the whole of Germany is waiting currently, when the hard Corona-measures are relaxed again. Also Hölscher has a forecast. He believes that first of all young people and students again "to normal life zurückkommen". Further, he says: "As a working population we will be moving for months with mouth protection in public life."

Furthermore, it is the most urgent task, is to protect the elderly and at-risk groups. Germany have a great advantage over others – especially southern European – countries. Of tropical medicine, says the "Zeit": "We have other social structures. Look at you, like in Italy, the families live together, three generations. In Munich we have per household of 1.5 people, as sad as that is, in normal times, but in this moment, this Situation comes to us."


Reported corona virus cases in Germany (click on your state)


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