[Corona child studies "Co-Ki": first results of a Germany-wide register on mouth and nose covering (mask) in children]./ Coronakinderstudien "Co-Ki": erste Ergebnisse eines deutschlandweiten Registers zur Mund-Nasen-Bedeckung (Maske) bei Kindern.

Background: Narratives about complaints in children and adolescents caused by wearing a mask are accumulating. There is, to date, no registry for side effects of masks. Methods: In the context of the www.co-ki.de multi-study complex, an online registry has been set up where parents, doctors, pedagogues and others can enter their observations. On 20 October 2020, 363 doctors were asked to make entries and to make parents and teachers aware of the registry. Results: By 26 October 2020, a total of 20,353 people had taken part in the survey. The group of parents alone entered data on a total of 25,930 children. The average reported wearing time of masks was 270 min per day. Of the respondents 68% reported that children complained about impairments caused by wearing the mask. Side effects included irritability (60%), headache (53%), difficulty concentrating (50%), less happiness (49%), reluctance to go to school/kindergarten (44%), malaise (42%) impaired learning (38%) and drowsiness/fatigue (37%). Discussion: This world's first registry for recording the effects of wearing masks in children is dedicated to a new research question. A bias with respect to the preferential documentation of particularly severely affected children or persons who are fundamentally critical of protective measures cannot be ruled out.The frequency of use and the spectrum of symptoms registered indicate the importance of the topic and call for representative surveys, randomized controlled trials with various masks and a renewed risk-benefit assessment of mask obligation in the vulnerable group of children.