AUTHOR=Laub Otto , Leipold Georg , Toncheva Antoaneta A. , Peterhoff David , Einhauser Sebastian , Neckermann Patrick , Borchers Natascha , Santos-Valente Elisangela , Kheiroddin Parastoo , Buntrock-Döpke Heike , Laub Sarah , Schöberl Patricia , Schweiger-Kabesch Andrea , Ewald Dominik , Horn Michael , Niggel Jakob , Ambrosch Andreas , Überla Klaus , Gerling Stephan , Brandstetter Susanne , Wagner Ralf , Kabesch Michael ,  Corona Virus Antibodies in Children from Bavaria (CoKiBa) Study Group , Aichholzer Bettina , Mair Georg , Wruk Michaela , Reischl Imke , Antos David , von Koskull Stephan , Becker Christian , Beer Elisabeth , Schirmer Hubert , Birkinger Georg , Blueml Andreas , Castrop Mona , Dieckerhoff Jost , Eichhorn Renate , Ewald Dominik , Fleck Gudrun , Heihoff Alfred , Geuder Jürgen , Grombach Jens , Gutdeutsch Peter , Segerer Florian , Habash Thomas , Habash Sonja , Harner Susanne , Herbst Christoph , Heuschmann Daniela , Hofmann Meike , Horn Michael , Jork-Kaeferlein Birgit , Schwarz Monika , Hopfner Reinhard , Judex Guido , Baumgartner Bastian , Corbacioglu Monika , Lindner Sabrina , Meinel Bettina , Bauer Alena , Löw Hannes , Szulagyi-Kovacs Annamaria , Kabesch Michael , Klein Annegret , Koering Cosima , Landvogt Niclas , Soehngen Claudia , Rasp Karin , Schick-Niedermeier Gudrun , Laub Marinus , Laub Otto , Leipold Georg , Schmid-Seibold Petra , Pawlak Johannes , Reitz Michaela , Puchner Georg , Razeghi Christiane , Razeghi Stefan , Rehe Christine , Rehe Klaus , Scheffel Matthias , Kaesbauer Ludwig , Schmid Roland , Strobelt Michael , Schoetzau Nina , Senjor Marko , Sperlich Michael , Theuerer Guenter , Steidle Guenter , Tretter German , von Arnim Victor , Volz-Fleckenstein Marlene 

TITLE=Symptoms, SARS-CoV-2 Antibodies, and Neutralization Capacity in a Cross Sectional-Population of German Children

JOURNAL=Frontiers in Pediatrics

VOLUME=Volume 9 - 2021

YEAR=2021

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2021.678937

DOI=10.3389/fped.2021.678937

ISSN=2296-2360

ABSTRACT=Background: Children and youth are affected rather mildly in the acute phase of COVID-19 and thus, COVID19 infection may easily be overlooked. In the light of current discussions on the vaccinations of children it seems necessary to better identify children who are immune against SARS-CoV-2 due to a previous infection and to better understand COVID-19 related immune reactions in children.  
Methods: In a cross-sectional design, children aged 1-17 were recruited through primary care pediatricians for the study (a) randomly, if they had an appointment for a regular health check-up or (b) if parents and children volunteered and actively wanted to participate in the study. Symptoms were recorded and two antibody tests were performed in parallel directed against S (in house test) and N (Roche Elecsys) viral proteins. In children with antibody response in either test, neutralization activity was determined.
Results: We identified antibodies against SARS-CoV-2 in 162 of 2832 eligible children (5.7%) between end of May and end of July 2020 in three, in part strongly affected regions of Bavaria in the first wave of the pandemic. Approximately 60% of antibody positive children (n=97) showed high levels (>97th percentile) of antibodies against N-protein, and for the S-protein, similar results were found. Sufficient neutralizing activity was detected for only 135 antibody positive children (86%), irrespective of age and sex. Initial COVID-19 symptoms were unspecific in children except for the loss of smell and taste and unrelated to antibody responses or neutralization capacity. Approximately 30% of PCR positive children did not show seroconversion in our small subsample in which PCR tests were performed.
Conclusions: Symptoms of SARS-CoV-2 infections are unspecific in children and antibody responses show a dichotomous structure with strong responses in many and no detectable antibodies in PCR positive children and missing neutralization activity in a relevant proportion of the young population.