Children develop long-term immunity to COVID-19

11. August 2021

A family study in Baden-Württemberg comes to the conclusion that children develop long-term immunity to COVID-19.

How does a COVID-19 infection work in children, are they protected after a mild course and what role do they play in the pandemic as sick people, sources of infection and intensifiers? Scientists from the university hospitals in Ulm, Freiburg, Heidelberg and Tübingen have examined these central questions in the COVID-19 child study initiated and financed by the state of Baden-Württemberg. They showed that children within the families were much less likely to be infected than adults and that the course was usually much milder. At the same time, the immune response in children was on average stronger and lasted longer than in adults, regardless of whether symptoms occurred.

Fewer symptoms, better immune protection

For the study, 328 families with at least one member suffering from COVID-19 were examined several times. A total of 548 children between the ages of 6 and 14 and 717 adults took part. In families with one infected person, children (34 percent) contracted the disease significantly less often than adults (58 percent) and – in the event of an infection – were five times more likely to be without symptoms (adults: 9 percent, children: 45 percent). Nevertheless, the children showed higher and longer-lasting specific antibody levels than adults eleven to twelve months after infection. This was true regardless of whether there were signs of illness or not. The children’s antibodies are very effective against various virus variants, so that children who are not visibly ill should also be protected after an infection. None of the infected children needed hospital treatment.

Signs of illness differ

Adults and children also differed in the reported complaints. While fever, cough, diarrhea and taste disorders were equally good indicators of infection in adults, only taste disorders were a clear indicator of COVID-19 infection in children (in 87 percent). A cough and fever were only indicative of an infection with increasing age from around the age of twelve. In summary, it can be seen that children who have recovered from COVID-19 develop a very effective and sustained immune defense against new coronavirus infections despite an often very mild or even symptom-free course. There are indications that children’s immune defenses even outperform adults.

For the study, 328 families with at least one member suffering from COVID-19 were examined several times. [Photo: Ulm University Hospital]