“Children are not virus hurlers”
Results of a scientific study on children and the coronavirus with political implications
The Bild newspaper referred to the results of the “Study on the Roll of Children in Spreading the Coronavirus” as a “bang”. Another newspaper, the Frankfurter Allgemeine Zeitung (FAZ), emphasised in its detailed report that - unlike with the flu - children under the age of ten are not “virus hurlers”, and that they don’t play a significant role in the spread of SARS-CoV-2. For the Baden-Württemberg state government, these results played a decisive role in the re-opening of nurseries, preschools and elementary schools.
“Children are less likely than adults to become ill. This could also mean that they are less infectious and don’t spread the virus as much either”, summed up Professor Klaus-Michael Debatin, director of the Department of Paediatrics and Adolescent Medicine at Ulm University Medical Centre. At a state government press conference held in Stuttgart in mid-June, Debatin presented the initial results of the study with Professor Hans-Georg Kräusslich, an infectiologist from Heidelberg. The study tracked 2466 parent-child pairs, a total of 4932 subjects. Applicants who had already been diagnosed with Covid-19 in a laboratory were excluded from participating. The study, which was commissioned by the state government and financed with 1.2 million euros, was carried out by the university hospitals in Ulm, Heidelberg, Freiburg and Tübingen.
The study analysed samples from the nose and throat area as well as blood samples. The research teams from the four participating hospitals tested the saliva samples for viral RNA, which provides indications of an acute infection. Three different procedures were used to search for SARS-CoV-2 antibodies in blood in order to determine whether a subject’s immune system had already reacted to these viral pathogens. Detecting antibodies in the subjects’ blood allows scientists to trace previous asymptomatic infections. The use of three different testing systems ensures that the tests are as accurate as currently possible in providing a picture of the course of the infections. The results of the analysis showed that one parent-child pair was acutely infected with the novel coronavirus. In 64 subjects, or 1.3 per cent of the participants, antibodies were detected in the blood, indicating a previous infection with SARS-CoV-2. What surprised the scientists was that, while there were 45 adults in the group of subjects with antibodies in their blood, only 19 children were in this group. This means that less than half of the children had been infected, even though the children were living in the same household with their parents at the time of the test, which was a requirement for participating in the study.
The researchers also wanted to find out if the risk of infection among children in emergency care situations was higher than the risk among children who were cared for at home. According to the statistical analysis, the risk is not higher. “Children are not only less likely to fall ill with Covid-19, but are also less frequently infected with SARS-CoV-2”, according to Debatin. The researchers surmise that children are better able to fight off the virus in the area of the nose and throat, from where the virus typically spreads. What’s more, ill children are much less likely to experience an overreaction of the immune system, which is often responsible for the life-threatening symptoms connected with Covid-19. Children also have fewer ACE2 receptors, which play a key role in the spread of the virus. These receptors are situated on the surface of many cells in the body and are, in a way, the decisive port of entry for the virus. They are found in the mucus membranes of the nose, but also in the lungs. The density of receptors is dependent upon the age of the infected individual, among other factors, and is closely connected to the virus’s success in penetrating the cell.
Children are less likely than adults to become ill with Covid-19. This could also mean that they are less infectious and don’t spread the virus as much.
“Following the joint announcement from the four participating university hospitals, which was distributed via the media and the schools in April, we received a flood of emails from parents who wanted to participate in the corona study with their children. More than 2000 interested parties contacted us just in Ulm and the Alb-Danube District”, explained Maria Zernickel. The medical documentation specialist was responsible for coordinating the study at the Ulm Children’s Hospital. In the end, the originally planned number of participants was increased from 4000 to 5000. However, only 720 parent-child pairs could be included from the Ulm area. “We were delighted by the huge response and would have liked to respond to all of the inquiries. Unfortunately, the limited amount of time available did not allow us to do so”, said Zernickel.
Minister President Winfried Kretschmann thanked the researchers from the four participating university hospitals in a press conference for their extraordinary cooperation. This remarkable cooperation made it possible for such a comprehensive and important study to be conducted with such impressive speed. It was also due to the results of the study that the state government was able to begin preparing the transition into a new phase. “New regular operation under pandemic conditions” just means that all of the children were finally able to return to preschools and elementary schools.
A follow-up study examines different immune reactions of adults and children
In mid-July, it was announced that the corona children’s study at the four university hospitals in Heidelberg, Freiburg, Tübingen and Ulm would be continued with a follow-up study. The follow-up study B, which is again based in Ulm at the Department of Paediatrics and Adolescent Medicine, is examining differences in the immune response of adults and children to SARS-CoV-2. 70 families with children and adolescents in the ages of zero to seventeen are participating in the part of the follow-up study being conducted in Ulm. A prerequisite for participation was that there must have been at least one verified coronavirus infection in each family. Blood samples and throat swab samples were taken from the 260 test subjects. The focus of the follow-up study is on the formation of antibodies following an infection with the coronavirus. Furthermore, an immune profile is being created and the immune response against the virus is being investigated. The researchers would like to find out whether, and if so, how the immune response differs between children and adults. Another aspect under investigation is the role of the receptor molecule ACE2 in spreading the coronavirus in the body. To this end, researchers are investigating the concentration of the corresponding receptor proteins in the blood and if there is a correlation between the level of the ACE2 concentration, the risk of infection and the severity of the illness. The first results of the follow-up study B are expected in the autumn.
