Corona children studies "Co-Ki": First results of a Germany-wide registry on mouth and nose covering (mask) in children

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: At the University of Witten/Herdecke an online registry has been set up where parents, doctors, pedagogues and others can enter their observations. On 20.10.2020, 363 doctors were asked to make entries and to make parents and teachers aware of the registry. Results: By 26.10.2020 the registry had been used by 20,353 people. In this publication we report the results from the parents, who entered data on a total of 25,930 children. The average wearing time of the mask was 270 minutes per day. Impairments caused by wearing the mask were reported by 68% of the parents. These included irritability (60%), headache (53%), diculty concentrating (50%), less happiness (49%), reluctance to go to school/kindergarten (44%), malaise (42%) impaired learning (38%) and drowsiness or fatigue (37%). Discussion: This dedicated Bias frequency

severely affected or who are fundamentally critical of protective measures cannot be dismissed. The frequency of the registry's use and the spectrum of symptoms registryed indicate the importance of the topic and call for representative surveys, randomized controlled trials with various masks and a renewed risk-bene t assessment for the vulnerable group of children: adults need to collecticely re ect the circumstances under which they would be willing to take a residual risk upon themselves in favor of enabling children to have a higher quality of life without having to wear a mask.

Background And Questions
The combination of precautionary measures recommended in Germany in 2020 to reduce the COVID 19 pandemic, or the AHA-L rule (distance/hygiene/everyday mask/ventilation), makes a signi cant contribution to containing the incidence of infection. The question of a certi cate of exemption from the obligation to wear a mouth and nose cover (hereinafter referred to as "mask") is a new phenomenon in pediatric practice. Parents, educators and doctors are increasingly reporting problems and health complaints in children in connection with wearing a mask. There are no manufacturer-independent studies on the use of masks for children and adolescents that are certi ed as medical products for occupational safety in professional applications. In addition, due to the unknown materials used, there are no ndings on the potential protective effects or side effects of the often home-made "everyday masks" worn by the majority of children. In view of the ongoing measures to contain the COVID-19 pandemic, and in particular the varying obligations for children and adolescents to wear masks in school over a longer period of time, there is an urgent need for research.

Study Design And Research Methods
Based on the registry of adverse drug reactions at the Paul Ehrlich Institute (www.nebenwirkungen.pei.de), an online registry has been set up where parents, doctors, educators and others can enter their observations on the effects of wearing a mask on children and adolescents. On 20. 10.2020, 363 doctors on the Co-Ki study distribution list were informed about the possibility of making entries there themselves and to communicate the registry to their patients and colleagues. The registry and the questionnaire can be found online at www.co-ki-masken.de (Figure in Online Supplement S1) as part of the Co-Ki study complex ( gure in Online Supplement S2). The data entered in the registry includes information regarding the role of the registrant, demographic data, previous illnesses, situation and duration of mask wearing, type of mask, existence of complaints from the child about an impairment via the mask, symptoms, behavioral problems, personal attitude to corona protection measures of the government and the possibility to leave name and e-mail address. A positive ethics vote from the University of Witten/Herdecke was obtained. The aim of this rst survey is to quantify subjective complaints in low-threshold absolute terms and to classify them in terms of content. This is done by reporting absolute and relative frequencies.
The distribution of gender, state or age with known expected values gives rst indications of the quota representativeness of the response behavior. Exploratory p-values by Chi² test are used to compare frequencies in the three selected age groups. For wearing time in minutes, the Kruskal-Wallis-H-test was used. Responses from all participating individuals were included. Incomplete answers as well as obvious false entries were excluded. In this rst analysis, only the responses from the largest group of "parents" are considered.

Results
By the evening of 26.10.2020, one week after the registry went online, 20,353 people had already taken part in the survey, with 48,657 entries. Of the survey participants, 17,854 (87.7%) were parents, 736 (3.6%) were teachers, 352 (1.7%) were doctors, and 1,411 (6.9%) were "others" ( Figure S3 in the Online Supplement shows the analysis set of the entries of the rst week). This article reports on the 17,854 entering parents with a total of 25,930 children and youth. The data of the entering doctors, teachers and other roles are published separately.
Of the 17,854 entering parents, 6,877 (38.5%) stated that they had a university degree (bachelor, master, master's degree, diploma, state examination, doctorate), 671 (3.8%) had a master craftsman, 3,704 (20.7%) had completed an apprenticeship and 3,040 (17.0%) had a high school diploma (general quali cation for university entrance) or subject-related higher education entrance quali cation or technical college entrance quali cation. 2,509 (14.1%) of the participants stated that their highest educational level was a secondary school leaving certi cate (In Germany: Mittlere Reife, Fachoberschulereife or similar), 327 participants (1.8%) had a secondary modern school leaving certi cate, and 31 participants (0.2%) stated that they had no school or training quali cation. The remaining did not enter an education. The participation of contributors per state corresponds to the distribution of the population (Figure 1).
The demographic situation of the children and previous illnesses among the children from the parents' point of view are shown in Table 1: the genders are equally represented with a slight trend towards boys; and 55.6% of the children were between 7-12 years of age. In 79.4% of the children it was stated that they had no previous illnesses, 5.9% had asthma and 1.8% had another lung disease. Furthermore, there was the possibility of free text entries on other previous illnesses, which was used by 8.6%.  of the survey participants answered that the child wears the mask at school outside of class, i.e. during breaks and in the corridors, 48.6% also stated that the child also wears the mask in class at the seat during lessons. 68.5% of the children recorded wearing the mask in stores and 39% on the way to school 4.6% of the children never wear a mask. A mask exemption certi cate had been granted to 6.7% of the registered children and youth. The average length of time the mask was worn varies greatly with age; it averaged 4.5 Page 5/16 hours per day, and was much higher, especially among youth (13-18 years), averaging 6 hours ( Table 2). In 16 913 children (65.2%) it was reported that fabric masks were worn, followed by surgical masks. FPP masks are hardly worn by children.
Regarding the question as to whether children themselves complain about impairments caused by wearing the mask, 67.7% of the respondents answered yes for their children; 26% answered no. The question as to whether the respondents themselves observed an impairment of the child by wearing the mask was answered yes in 66.1% ( Table 2). The assessment of the health impairment is shown in Table 3.
Four percent had no opinion when asked about their personal attitude to the government's corona protection measures, 11.7% of the participants thought that the measures should be more stringent, 11.0% considered the current measures appropriate and good and 41.7% were in favor of milder measures. A further 31.6% expressed a different opinion than the setting option speci ed in the selection option. In general, they described the policy measures as inappropriate, incomprehensible and undifferentiated. The frequency distribution of the above-mentioned side effects associated with masks is similar in the different age groups, with headaches, concentration di culties, discomfort, learning di culties and drowsiness / tiredness being the most common (Table 3). Other complaints were described in the free text.
First of all: 269 entries on worsened skin, especially increased pimples, rashes and allergic phenomena around the mouth area up to fungal diseases in and around the mouth. There were 151 entries on nosebleeds, 122 entries on school displeasure up to school anxiety / refusal to attend school, 64 entries on increased sweating, 52 entries on pressure points and wounds behind the ears, 46 entries on sore or cracked and partly bloody lips, 31 entries on increased migraine attacks in frequency and severity, 23 entries on impaired vision, 13 entries on aphthae. Table 3 shows the classi cation of a possible health impairment of the children, as assessed by the parents. Table 4 shows further behavioral problems in the children, above all with 60.4% an increased irritability, 49.3% less happy children, 44% children who do not want to go to school anymore, in each case children in the age category 7-12 years are affected most. In 25.3% of the children it was stated that they have developed new anxieties (Table 4). In addition, 2,672 entries in this question alone mention explicit speci cations of anxiety or the reappearance of several anxieties in free text entries. In addition to a general fear of the future, the fear of suffocation even with a mask, as well as the fear of death of relatives through corona, is most frequently represented. In addition, there is the fear of stigmatization both by wearing and not wearing a mask in the social environment.
Many parents also report nightmares and anxiety disorders that relate to masked people whose facial expressions and identity are not recognizable to the children. A detailed evaluation and publication of the free text entries is planned.

Discussion
The reported) were between 10 and 19 years of age [1]. This is less than the number of children reported in this registry within one week. It is still unclear whether children are less likely than adults to be infected with SARS-CoV-2 and transmit the infection to adults in such a way that the latter become seriously ill [2][3][4][5].
However, it has been shown that the majority of infected children, especially up to the age of 10, develop no or only mild symptoms [6][7][8][9]. In rare cases, children up to the age of 10 years develop severe courses of the disease. The one child and two adolescents who have died of COVID-19 (as of 25.10.2020, not yet described in detail by the RKI) had chronic pre-existing conditions [10,11]. In Europe, children under 10 years of age rarely seem to be spreaders in this infection process, although data from India, a country with a different hygiene background, do ascribe a certain transmission role to children (although without differentiation between 5-year-olds and 17-year-olds) [12]. A Scottish study of 300 000 households found that the more children in the household, the less likely adults are to be hospitalized with COVID-19 [13]. A recent study suggests that children emit less aerosol when singing and talking than adults [14].
That mask-wearing in adults can, in principle, be a safe, effective, and cost-effective measure to slow the COVID-19 pandemic is unquestionable [15][16][17]. Based on our data, it can be said that the effects of compulsory masks on the quality of life and presumably also on the health of individual children should not be ignored by politics and society. While many children tolerate the mask relatively easily, there are clearly children who cannot be expected to wear a mask in good conscience, especially when the mouth and nose protection in smaller children is not necessary. Parents, teachers and doctors report stigmatization, exclusion and aggressive behavior towards children who do not wear a mask for psychological or medical reasons. Inappropriate use of masks, which tends to be the case in children, may increase the risk of pathogen spread and transmission through the increased tendency to put their ngers in their face, and may thus be worse than not wearing a mask at all in some cases [18]. Looking at the symptom spectrum of the complaints, 66.1% of the interviewees show a clear and broadly diversi ed burden of complaints, both in the physical (rashes, headaches, etc.), as well as in the mental (fears, irritability, etc.) and intellectual (concentration disorders) areas in the children of the interviewees. In addition to acute health impairments with, in individual cases, signi cantly experienced health impairments, the long-term effects on the various developmental areas that go beyond well-being, such as language, play, learning, communication, sensomotoric development and empathy of children are di cult to assess. The often mentioned headaches and concentration di culties should be seriously explored in their importance for cognitive development. It is noticeable that the distribution of complaints ts well with the age of the children (Tables 3 and 4), which supports the plausibility of parental input.
Direct effects of indoor CO2 concentration on cognitive functions have been demonstrated [19,20]. This is not directly transferable to the air breathed under the masks, but increased CO2 concentrations could occur under some mask types. This may be particularly true in small children with large fabric masks, which sometimes have a thicker material and which were used particularly frequently by the children in the registry (65.2%). Families are currently free to choose their children's mask type according to the thickness of the material and thus there is still a margin between breathable and multi-layer, rather airtight models, yet the problem remains that parents, regardless of whether or not they themselves approve of the corona protection measures, can overburden their children through ignorance or fear of infection by using masks that are inappropriate for their child. A bene t-risk analysis is therefore called for. However, this is complicated by the fact that the study situation is extremely weak both in terms of bene ts and risks. Both the calculations of a bene t from masks and almost all studies of the risks of masks are based on adults.
It must also be assumed that the SARS-CoV-2 protection standards for schools, such as those of the German statutory accident insurance, are not known everywhere [21]. In particular, they contain recommendations on recovery times when wearing masks for schoolchildren with short breaks and, at the latest after three hours of wearing, a subsequent recovery time of 15-30 minutes [21].
Limitation of the results: Even though the rapid development of the registry and the high number of participants within a few days is impressive, this rst evaluation of the Co-Ki mask registry has limitations. The fact that 38.5% of the participants indicated a university degree could be an indication that the registry was not equally accessible to all groups of people as an online version and due to its complexity.
All online registries have this problem. A reporting bias (also with regard to the preferential documentation of particularly severely affected children) cannot be ruled out. In addition, the link to the registry was also found in social media forums, among other places, which criticize the government's corona protection measures in principle, which is partly re ected in the results of the query on attitudes to the government's corona protection measures. At the same time, other participants reported that their children had no complaints. Furthermore, there is no control group. The data relate to suspected cases of adverse reactions, i.e. medical events observed by parents in the context of mask use in children, but not necessarily related to or caused by the mask.
Both the gender distribution and the distribution of participants according to federal states, as well as the distribution of symptoms according to age, speak in favor of the data being representative for the German population of children. With a few exceptions, the data sets in the free text entries re ect differentiated, sincere parents and, taken as a whole, provide a balanced overall picture with a plausible spectrum of symptoms and a comprehensive description of the impairments observed in children in connection with the mask. The hundreds of incoming e-mails to the study initiators, including questions about the existence of the registry, speci cation and completion of the entries made by participants, detailed case descriptions and suggestions for further research, are a further indication of the high relevance of the topic and the honesty with which many participants address the question. Naturally, an openly accessible registry can never provide a medical counter-validation of all submissions. The number of entries in the registry is continuing to increase daily. The registry questionnaire will be expanded and validated on the basis of the new symptoms entered by parents in the free text information.

Conclusion
The number of new SARS-CoV-2 infections is currently at a high level. Many children are subject to great challenges and families try to master these as best they can. At least for children over 10 years of age, it is important to follow the well-known rules of AHA+L: Keep your distance, observe hygiene, wear an everyday mask, and ventilate regularly. The most recent statement "on the use of masks in children to prevent SARS-CoV-2 infection" [22] states, "For children, there are few data on possible adverse effects of masks." The Co-Ki mask registry provides initial results in this regard, and these call for age-and situation-dependent studies to provide a sound risk-bene t analysis. While the proportion of people tested positive for SARS-CoV-2 and also the number of intensive care patients in Germany is high in many places, we report here on a relatively small, unrepresentative problem: several thousand children who seem to suffer from wearing the mask or who may experience health problems from the mask. Our study provides the basis for a representative survey on which a precise bene t-risk analysis of mask wearing in children can be built.
It is very important to us that our results do not lead to parents developing a fundamentally negative opinion of mask-wearing among children. Many children and adolescents are grateful that they can continue to attend school thanks to the AHA+L rules and would like adults to have a positive opinion about the masks, especially since the type of mask worn can usually be chosen. Furthermore, there are children for whom the mask may be a necessary aid, for example, if they are immunosuppressed after chemotherapy. Unre ective negative statements about the mask can cause a nozebo effect and unnecessarily stress children: it is better to listen and take it seriously when problems arise.
"Conclusion for the practice" -A certain percentage of children and adolescents have non-negligible complaints when wearing the mask. These children should not be stigmatized.
-This worldwide rst registry on side effects of the mask re ects the spectrum of symptoms in children and adolescents.
-A precise bene t-risk analysis is urgently required. The occurrence of reported side effects in children due to wearing the masks must be taken seriously and requires a precise clari cation of the accompanying health circumstances, the situation of wearing the mask (duration, breaks and mask type) and the school situation.
-Furthermore, all parents, doctors, pedagogues and others are invited to participate in www.co-kimasken.de to document their observations on effects that occur when wearing the mask. The registry will also be available in English from 15.12.2020.
-Restraint with negative statements about the mask is appropriate to avoid nocebo effects.