Annette-Gabriele Ziegler, who led the research project, says: “We carried out antibody tests on children and found that more than six times as many had contracted the coronavirus than previously assumed.”
Between January and July 2020, the researchers tested blood samples from some 12,000 Bavarian schoolchildren for SARS-CoV-2. Study participants ranged from just 1 year old to 18 years old. One-third of those who lived with family members who had tested positive for the virus had traces of SARS-CoV-2 antibodies in their blood.
Approximately half of these children remained symptomless. Antibodies against SARS-CoV-2, incidentally, can be detected only after between one and four weeks after infection.
As many children remain symptomless despite contracting the virus, many have underestimated their role in spreading the virus. Annette-Gabriele Ziegler says kindergartens and schools must therefore adopt much stricter preventive measures to help contain the pandemic. These include social distancing, ventilating classrooms, and teaching small groups of pupils. She says that in addition, schoolchildren should be screened more rigorously for the virus even if they are symptomless.