Sunday, November 28

High student incidence – “Leave schools open and test a lot”

“All the examples that exist in the past always show that closing is worse than leaving schools open and testing a lot,” says mathematician Jan Mohring. (picture alliance / dpa)

With the increasing corona numbers, concerns about renewed school closings are growing. Brandenburg is currently considering lifting compulsory schooling. In fact, the incidences are particularly high among high school students. The incidence of 10 to 19 year olds nationwide is almost 600.

“The under-15-year-olds are just as hot as the under-35-year-olds”

But what is actually behind this almost 600? What role do schoolchildren play in the current pandemic? Jan Mohring, mathematician at the Fraunhofer Institute in Kaiserslautern, said in the Dlf that the high numbers among schoolchildren are also due to the fact that in the age group from 0 to 14 the detection rate is twice as high as in the following age group of 15 to 34 Year olds. “That means that the young children are not the drivers, they are simply discovered more strongly,” says Mohring.

The interview in full:

Jan Mohring: Yes, I have to go into a bit of a start at how we answer such questions. And with our models we always try to simulate reality, that is, we have model parameters there and we turn them around until our predicted spread dynamics spits out the same reported cases as those that also occur at the RKI. And the essential model parameters there are of course the contact rates between the different age groups, vaccination rates, things like that, but also, very importantly, the detection rate per age group. Yes, and then something really interesting comes out of it.

“The young children are not the drivers”

If you look at the reported figures, you can clearly see that in the age group 0 to 14, the infection rate is about twice as high as in the following age group, the 15 to 34 year olds. And the obvious thought would then be, okay, the unvaccinated children, these are the drivers of the pandemic. But if we now look at what our model is spitting out, that says a different reason, namely that the detection rate is twice as high among the boys as in the following age group. In other words, the young children are not the drivers, they are simply discovered more strongly, and that is the reason.

Kathrin Kühn: This means that we cannot simply compare the incidences between these age groups so one-to-one.

“Pupils are tested much more often”

Mohring: Yes, exactly, because the incidences always relate to the reported figures, and if many more are discovered in one age group, then they have a higher incidence, although in fact it is not spreading more widely among these sections of the population. So you mustn’t always rely on what is reported, but you always have to consider what is actually boiling under the surface? And there it shows: This is simmering with the under-15-year-olds as well as with the up to-35-year-olds. There is hardly any difference. Just the boys, they are discovered much more often because they are tested much more intensely.

More on the subject of mandatory vaccinations

Bold: You are now addressing the school tests, so that nowadays the younger generation is actually being screened everywhere.

Mohring: Yes it is. In some federal states that had been suspended. So in Thuringia, for example, it was suspended two weeks after the summer vacation, which wasn’t so great. In Rhineland-Palatinate, the test rate has now been reduced from twice a week … The last week was then reduced to just once. That wasn’t great either. But overall it is like this: students are tested far more often than the rest of society, so it is a good indicator of what is actually seething beneath the surface. And there is just very important: only the unvaccinated are actually tested, unlike in the past. So in the past all children were unvaccinated and they were all tested, that was a super monitor, what really happens, now it’s just a limited monitor because we really only see the unvaccinated and the vaccinated children who are not now tests more, they can have it too. Therefore, from my point of view, it is rather a bit disastrous that you only test the unvaccinated.

“The more I test, the better it is”

Bold: What advantage could that give us if all children and adolescents in the age group are tested again? Do your models possibly also see positive effects here?

Mohring: In the end, the net effect is: if you test people a lot, you see a lot more at the beginning and you get shocked. But in the long term, if you discover a lot, then many will be quarantined, all these people can no longer throw off the remains of their virus load. You can also discover children’s parents and family members, who are then often infected as well. So in the end: the more I test, that doesn’t just apply to schoolchildren, the more I test, the better it is to get the pandemic under control. With the students, unfortunately it is the case, they are now the victims of our society, so they always have to pay for everything, or rather, the students, who still know that you are not selfish, and they drag it along because they want to protect their parents and grandmas and grandpas. This lack of egoism, I would like to wish that for the older generations, yes.

Detection rate drops sharply in older age groups

Bold: Can you say something about the dark field in the older age groups? So what does that possibly look like? If we can now come in the direction of full coverage in parts of the younger, how much do we not know about the older?

Mohring: Yes. So we checked what our model adaptation was spitting out. If you have different age groups, then you can work out how roughly the relative detection rate is or the relative number of unreported cases, and I’ll tell you that now.

Let’s take the next age group, the age group 15 to 34, where our model adaptation says that the detection rate there is only about 50 percent of what is measured in the very young children up to 14, i.e. only 50 percent there. And then things get a little better in the parents’ generation, let’s put it that way, the detection rate is still 63 percent of the very young children, and then around 58 percent of the over-60s, our model adaptation says. To put it very roughly: Young students have a certain rate of discovery, and the following age groups have roughly half of it.

“The net effect is that it is better to leave schools open”

Bold: Very exciting. I’ve never heard it like that before. What does that mean now? What if the schools were closed now? What do you think?

Mohring: Yes, it is not the case that we have no experience there. There was a study in Bavaria by a working group led by Mr. Kauermann, who investigated exactly that. At the time, the debate was whether schools should be closed in Bavaria or should be left open. And in some districts one thing was done, in others the other. And then it came out that the net effect is that it is better to leave schools open. You have two effects. So if you close the schools, the children can no longer infect anyone or they can infect each other less. And the other effect is: if I leave them open, then I discover more and then I can quarantine more. And from the outset it is not clear which of these two effects is the stronger. But this study by Mr. Kauermann has clearly shown for Bavaria: The net effect is that it is better to leave schools open and have a higher detection rate. So all the examples that exist in the past always show: Closing is worse than leaving schools open and testing a lot.

Bold: Then the final question. So if you now come up with the idea of ​​closing schools as perhaps one of the last steps, does that mean that at the same time it must be completely prevented that contacts can still take place in this isolated environment? So closing schools without closing companies, for example, then makes no sense?

Mohring: Yes, I would support that. You have to imagine the following: I said earlier that the young students are not the drivers, but the students are discovered much more often and thus contribute to better quarantine and the fight against the pandemic. So if you just send the students home specifically and not the rest, then we won’t meet a particularly contagious group, but we will meet precisely the group that makes sure that we can follow and discover the matter. So it would be the wrong thing to do now.

// Statements by our interlocutors reflect their own views. Deutschlandfunk does not adopt the statements of its interlocutors in interviews and discussions as its own. //

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