Corona: how contagious are children?

Christiane Fux studied journalism and psychology in Hamburg. The experienced medical editor has been writing magazine articles, news and factual texts on all conceivable health topics since 2001. In addition to her work for, Christiane Fux is also active in prose. Her first crime novel was published in 2012, and she also writes, designs and publishes her own crime plays.

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Children rarely get seriously ill with Covid-19. Is that why they are less contagious? New studies provide evidence. The assessment could help decide when daycare centers and schools open again for younger people.

When children become infected with Sars-CoV-2, the disease is very rarely severe. Often they even develop no symptoms at all. Then why are they not allowed to go to kindergarten or school? The answer to this: Children can also become seriously ill. Above all, however, they infect others and could thus contribute significantly to the spread of the virus. But how infectious are the little ones really?

A team led by Charité virologist Prof. Christian Drosten has found evidence of this. The researchers evaluated samples from almost 4,000 infected children, adolescents and adults that were examined between January and April 26 in various Berlin test centers. For this purpose, swabs were taken deep from the throat of the tested, where the virus multiplies particularly strongly.

High virus concentration even in symptom-free children

The amount of Sars-CoV-2 virus that the researchers determined was similar in all age groups examined - including children. "This is interesting because we know that there is only a certain concentration of infection," says Drosten on the NDR podcast. One can therefore assume that infected children infect others just as easily as adults.

Little data available from children

However, the crux of this study is that the proportion of children examined is very low. Of the around 60,000 people who were examined in Berlin test centers, 3712 were Sars-CoV-2 positive. Among them were 37 children up to the age of 6, 16 others up to ten years. “We actually should have examined ten times more,” says Drosten. But there are not enough young tested people in the world. "In this respect, it was an emergency solution, but it can provide important information."

The problem is understandable: If children have hardly any symptoms, they are correspondingly less tested. In addition, parents are reluctant to present their children to test centers, where many potentially infected people are waiting for a test. “I won't take my children with me,” says Drosten, who is a family man himself.

Mild symptoms, lots of viruses

This could also mean that the study data are biased: Children with mild symptoms may have less virus in their throats than those in the study.

Drosten and his team have found out: the opposite is the case. Symptom-free infected people, regardless of whether they are children or adults, have even higher viral loads in the throat.

Previous studies show why this is so. They show that at least infected adults shed large amounts of the virus even if they did not develop symptoms. A large proportion of the infections (around 40 percent) also take place before the first signs of the disease appear.

The explanations: If symptoms occur, the immune system is already very active in advance - then you will find fewer and fewer viruses in the smear very quickly as the disease progresses. "The virus concentration is on the decline," says Drosten.

No virological arguments for openings

So one cannot assume that children who are silently infected carry less virus in them. Against the background that younger children cannot comply with distance rules and contact restrictions independently and that it is hardly possible for them to wear masks, opening schools and childcare facilities for younger people currently seem rather problematic.

However, it is still unclear how often children become infected. If this were much less the case than with adults, it could make it easier to reopen the care. But that is very difficult to judge at the moment. Since they are currently largely isolated from social life, they are rarely infected at the moment and hardly contribute to the spread. That could change quickly with the opening of daycare centers and schools.

Do children get infected less often?

But there are indications that point in the other direction. There are studies that indicate that children were actually less infected in advance under natural conditions, reports Drosten. To this end, scientists in Shanghai, for example, observed who became infected in a recently published study in families of infected people.

Overall, the contagion factor in such families is 12 to 15 percent. For children, so the result, the risk is only one third of adults. Older people, on the other hand, are 1.5 percent more likely to be infected than the rest of the people examined.

Why is still unclear. This may have something to do with the more powerful first immune defense of young and very young people. It decreases with age.

But here, too, there are special situations: unlike in a family who may already know that a virus could be rampant, children in daycare or school could maintain closer contacts.

No all-clear at the moment

The conclusion: the all-clear from the virologist and a plea for daycare and school openings cannot be derived.

In view of the tense situation in families, the virologist Drosten pleads for at least opening playgrounds again. Infection could be much less likely in the fresh air. A corresponding relaxation actually belongs to the decisions of the federal government on Thursday. How much they actually relieve families with young children remains to be seen.

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