Corona study: the role of daycare children remains unclear

Florian Tiefenböck studied human medicine at the LMU Munich. In March 2014, he joined as a student and has supported the editorial team with medical articles ever since. After receiving his medical license and practical work in internal medicine at the University Hospital Augsburg, he has been a permanent member of the team since December 2019 and, among other things, ensures the medical quality of the tools.

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What role do children play in the spread of the coronavirus? The University Hospital Düsseldorf has now published one of the largest studies on this question in Germany. But a clear answer cannot be derived from this.

As part of the study, scientists from the Institute for Virology at the University Hospital Düsseldorf examined more than 5200 children and employees in Düsseldorf day-care centers. In almost 35,000 samples, only one infection was found in one child. The published manuscript has yet to be reviewed by independent researchers.

Result without meaningfulness

The aim of the study was to gain reliable knowledge as to whether new corona cases occur in the daycare groups and whether chains of infection are triggered in the surrounding area. The evaluation shows that during the study period the frequency of new infections in the daycare centers was at the same level as for the city of Düsseldorf as a whole, explained Professor Jörg Timm, director of the lead institute for virology at the university clinic.

"The frequency of infections in daycare children most closely reflects the infection rate in the population as a whole," said Timm. But he also emphasizes: "On the basis of the pleasingly low number of infections, a clear statement is made about the importance of children as a source of infection, Unfortunately not possible."

Measurement based on spit samples

From June 10 to July 7, 3955 children and 1255 employees took part in the model study. They were screened for infection with the novel coronavirus twice a week over a period of four weeks. The university clinic's laboratory analyzed almost 35,000 spit samples using a PCR test. In total, more than 8100 children are registered in the 115 daycare centers involved.

Only a six-year-old child tested positive for Corona. After the infection became known, the mother and a sibling also tested positive. In addition, the course over time indicates that Sars-CoV-2 was transmitted to another child within the daycare center and from there to household members. However, the samples from this further case were not available to the researchers. As a result, the situation could ultimately not be clarified with certainty.

Other infections outside of the study

According to the city's health department, there were further corona infections in children and employees in the 115 participating institutions during the four-week study period, but they did not take part in the study. A total of ten new infections were recorded - two among staff and eight among daycare children.

The daycare children who tested positive in the facilities participating in the study but were not among the test subjects had mostly become infected in their home environment. During the study period, a total of 501 corona infections were reported to the health department in Düsseldorf. These included 32 infections in children of kindergarten age. 16 of these infected children were in a care facility.

Reasons for study result unclear

According to the authors of the study, the reasons for the surprisingly low number of only one positive case in the test series have not been fully clarified. In their report, they first emphasize the “excellent” return rate of the spit samples with an average of over 80 percent.

Although they consider the measurement method to be suitable and sufficient overall, they also attest to weaknesses in the method. On the one hand, it may be less sensitive - it would then detect sick people less reliably than other tests. On the other hand, the samples were obtained unsupervised and therefore not standardized. Reports from parents also suggest that the samples may not be certain to be reliable.

Furthermore, the families who did not want to take part in the study presumably had a different awareness of the problem, according to the researchers. The families who had agreed to the examinations, on the other hand, could take the risk of infection more seriously and accordingly comply more consistently with recommended protective measures. In view of the generally small number of cases, there would also be considerable statistical uncertainty.

Do voluntary corona tests make sense?

The positive corona cases in daycare children and staff outside the study were found in event-related tests. The scientists conclude from this that a voluntary regular test screening in the current infection process for the determination of corona cases is "not superior". "The effort is currently not in a favorable relationship to the benefit." In her opinion, however, this could change if the number of new infections increases. (ft / dpa)

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