key: cord-0707410-ig4i5uh5 authors: Eberhart, Martin; Orthaber, Stefan; Kerbl, Reinhold title: The impact of face masks on children—A mini review date: 2021-02-21 journal: Acta Paediatr DOI: 10.1111/apa.15784 sha: b7176ae86b411138450328adb9e6ef6374350e45 doc_id: 707410 cord_uid: ig4i5uh5 AIM: Face masks are essential during the COVID‐19 pandemic, and the United Nations Children's Fund and the World Health Organization, recommend that they are used for children aged six years and older. However, parents are increasingly expressing concerns about whether these might be physically harmful. This mini review assessed the evidence. METHOD: We conducted a narrative review on the effects of mask wearing on physiological variables in children, using PubMed, the Cochrane Library and the World Health Organization COVID‐19 Database up to 7 November 2020. The lack of paediatric studies prompted a second search for adult studies. RESULTS: We only found two paediatric studies, published in 2019 and 2020. The 2020 study was not related to COVID‐19. Only one study, performed with N95 respirators, collected medical parameters, and this did not suggest any harmful effects of gas exchange. The eight adult studies, including four prompted by the pandemic and one on surgeons, reported that face masks commonly used during the pandemic did not impair gas exchange during rest or mild exercise. CONCLUSION: International guidelines recommend face masks for children aged six years and older, but further studies are needed to provide evidence‐based recommendations for different age groups. harmful for their children. Fake news about the negative effects of face masks has also been rising. This has included false reports about face masks causing an increasing number of illnesses and even deaths among children. 8 These reports argue that face masks may lead to increased rebreathing and accumulation of carbon dioxide, which could be harmful or even deadly. The Italian Paediatric Society published a statement describing face masks for children as harmless, but failed to provide scientific data to back this up. 9 In addition, a group of Portuguese paediatricians supported the use of face masks for children without providing sufficient evidence. 10 The very limited information about the use of face masks, especially for children, was also highlighted in the advice issued by the United Nations Children's Fund (UNICEF) and the World Health Organization (WHO) on 21 August 2020. 5 This followed the principle of do no harm and stated that children aged five years and under should not wear masks. The guidance also states that young children probably do not have the fine motor coordination to use a face mask appropriately and are unlikely to be able to show the level of compliance required. The guidance recommends a risk-based approach for children aged 6-11 years of age and children aged 12 and over should be treated as adults when it comes to wearing masks. 5 School closures due to the COVID-19 pandemic are a massive disruption to children's physical and mental well-being 11 and may have massive long-term effects. 12 As proposed by United Nations Children's Fund, keeping schools open should be a priority in order to minimise further harm. 13 Despite the lack of appropriate evidence, school children wearing masks also during lessons may be a promising element to guarantee open schools during the COVID-19 pandemic. The aim of this narrative review was to describe the existing knowledge about children wearing face masks. We searched PubMed, the Cochrane Library and the World Health Organization COVID-19 Database up to 7 November 2020. Because paediatric studies on this subject were very limited, the search, which was limited to papers published in English, German or French, was extended to cover adults' studies as well. Only two studies performed in children could be found. 14, 15 Both studies aimed to assess the wearability of N95 respirators, which are designed for children's protection against air pollution. The first, published in 2019, assessed the safety, fit and comfort of the masks and the second, published in 2020, looked at the subjective wearability perceived by primary school children. In addition, eight studies performed in adults could be found. All 10 studies are summarised in Table 1 , some details are mentioned as follows: Goh et al performed a randomised, two-period crossover study on 106 children, aged 7-14 years, in Singapore to evaluate the safety of N95 respirators. 14 The children were asked to wear a mask both for five minutes while they were at rest reading and then when they walked on a treadmill for five minutes. When they were resting their mean end-tidal carbon dioxide was 30.9 ± 3.37 mmHg without a mask and 34.3 ± 3.32 mmHg when they were wearing a mask. During mild exercise, their end-tidal carbon dioxide values were 28.2 ± 2.8 mmHg and 32.0 ± 2.9 mmHg. All their physiological variables, including their heart rate and respiratory rate, were within acceptable ranges and the children's mean oxygen saturation was at least 99% in all cases. The authors reported that seven of the 106 (6.6%) children experienced mild breathing difficulties, but this subjective feeling was not correlated with the objective data provided on the physiological variables. The carbon dioxide levels were lower for N95 respirators with micro ventilators than for masks without filters. 14 The second paediatric study, performed by Smart et al in London, UK, assessed the wearability of three different N95 respirators in 24 primary school children aged 8-11 years. The children were asked to walk for three minutes and run for three minutes. No physiological parameters were obtained, but the subjective perception of the children about comfort, breathability, heat and fit of the three masks while walking or running was assessed by using a Likert scale. The masks had no subjective negative impact on breathing during walking. When the children were running, one of the three masks had a slightly negative impact on their subjective perception of breathing. The main complaint was that their face was hot. Additionally, subjective discomfort was reported for one of three masks. 15 Due to the lack of further paediatric studies, we included eight studies carried out with adults (Table 1) . [16] [17] [18] [19] [20] [21] [22] [23] These included four studies published in 2020, which were prompted by the COVID-19 pandemic. 20, 21, 22, 23 One of the eight studies was carried out on surgeons who performed operations lasting from one to four hours, 18 and the rest were on patients, 20 medical staff 17, 20, 22 or members of the public. 16, 19, 21, 23 All the studies obtained oxygen saturation and heart rate data. Participants' respiratory rate and carbon dioxide levels were obtained in six of eight studies. 16, 17, 20, 21, 22, 23 Of the eight studies, five provided data on controls without masks. 16 • Our mini review only found one paediatric study, and eight adult studies, which explored the medical parameters of mask wearing, and these did not report any harmful effects. • Further studies are needed so that evidence-based recommendations can be produced for different age groups. [14] [15] [16] [17] [18] [19] including four studies prompted by the COVID-19 pandemic 20 The adult studies showed no evidence of harmful effects when surgical or cotton masks were worn. For example, there was no significant impairment of oxygen uptake, in terms of oxygen saturation, when the participants wore the masks. [16] [17] [18] [19] [20] [21] One pre-pandemic study showed a mild increase in heart rate and respiratory rate after one hour of walking when using a surgical mask. 16 However, five other studies did not detect a compensatory increase in heart rate, [17] [18] [19] [20] [21] including two of the four studies prompted by the pandemic, 20, 21 and the study related to surgeons. 18 One study prompted by the pandemic, Fikenzer et al, performed ergo-spirometry in adults to measure their cardiorespiratory responses during heavy exercise while wearing a surgical face mask or an N95 respirator. The results were compared with controls without masks. Pulmonary function parameters, such as forced vital capacity and peak expiratory flow, were significantly lower when surgical masks were worn. However, no significant difference in minute ventilation volume and respiratory rate could be proven while wearing a surgical mask. At the peak of the power exertion test, there were no crucial differences in gas exchange parameters, such as the partial pressure of oxygen or the partial pressure of carbon dioxide. A decrease in maximum achievable power was observed when the participants used an N95 respirator, but not when surgical masks were used. Discomfort was significantly higher with any mask. 22 Another study prompted by the pandemic, by Epstein et al, used cycle ergometry to induce physical activity without a mask, with a surgical mask and with an N95 respirator. Heart rate, respiratory rate, oxygen saturation and time to exhaustion did not differ significantly under different conditions. There were no differences in end-tidal carbon dioxide in the no mask controls, and those who wore surgical masks, except for the last and heaviest workout stage. However, a significant end-tidal carbon dioxide increase was found when N95 respirators were worn. 23 This mini review identified a lack of information on the consequences of children wearing face masks. This gap in the knowledge was also highlighted in the advice issued by the United Nations Children's Fund and the World Health Organization on 21 August 2020. 5 The paediatric study by Goh et al, published in 2019, showed that children did not experience any harmful physical effects when they wore N95 respirators. However, this study had several limitations. The resting and walking tests only lasted five minutes each and did not correspond to usual wearing time. This means that no conclusions on the long-term effects can be reached. 14 Having said that, similar adult studies that had a longer duration of mask use did not report significantly different results about gas exchange. 17, 21 The study published by Smart et al in 2020, which related to air pollution not the pandemic, focussed on subjective perceptions and did not provide any information about physiological parameters. The authors reported that the primary school children did not feel discomfort or strong breathing impairment neither during walking nor during running. 15 The eight studies conducted with adults were heterogenous in terms of study design and evaluated parameters. The pandemicinspired study by Fikenzer et al reported that wearing surgical masks during heavy physical exercise negatively affected minute ventilation volume, cardiopulmonary exercise capacity and comfort, but not blood gas parameters and power performance. 22 Another Another important issue is whether masks are available that are the right size and fit for children. Van der Sande et al argued that using face masks that were not specifically designed for children could lead to significantly inferior protection and unwanted side effects. 27 The letter by Jin et al also recommended face masks that were specially designed for children, arguing that they would provide the best functionality and safety. 25 The two paediatric studies mentioned above 14,15 examined the use of N95 respirators in a setting of air pollution. No studies exist thus far concerning the use of surgical or cotton masks in children. Compared with adults, children's maximal inspiratory and expiratory pressures are lower than those in adults, 28 showing a positive correlation between biometric data and age. 29 In a pre-pandemic study conducted by Lee et al, it is shown that wearing an N95 respirator leads to a 126% increase of inspiratory and a 122% increase of expiratory flow resistances. 30 31 The authors concluded that face masks did not cause any clinically relevant changes in oxygen or carbon dioxide concentrations. However, others have argued that frequently wearing face masks might have a negative impact on basic psychological needs, like individual autonomy. These may, in turn, reduce mask wearing compliance in society. 31 This aspect should also be considered in upcoming paediatric studies that are likely to be performed in near future. This review was restricted to potential physiological alterations induced by conventional face masks and did not cover the psychological and social consequences. Only two studies were available that dealt with the potential harmful effects in children and more information had to be obtained from adult studies. None of these studies examines periods as long as a full school day. Information about the influence of commonly used face masks on physiological variables is very limited, especially for children. The few existing studies suggested that surgical and cloth masks did not significantly compromise ventilation and oxygen supplies in healthy individuals and may, therefore, be considered as not harmful. Physical exercise and pre-existing respiratory problems may cause hypoxaemia and hypercapnia. As using face masks could be a longterm preventive measure in the COVID-19 era, further studies are needed, particularly to explore the impact on pre-existing respiratory problems in children and adults. None. The authors have no conflicts of interest to declare. https://orcid.org/0000-0001-8435-8349 Centers for Disease Control and Prevention. COVID-19: Considerations for Wearing Masks European Centre for Disease Prevention and Control. Using face masks in the community -Reducing COVID-19 transmission from potentially asymptomatic or pre-symptomatic people through the use of face masks Bedeckung im öffentlichen Raum als weitere Komponente zur Reduktion der Übertragungen von COVID-19. Strategie-Ergänzung zu empfohlenen Infektionsschutzmaßnahmen und Zielen (3. Update) [Mouth and nose covering in public spaces as a further component to reduce the transmission of COVID-19 the-use-of-masks -in-the-commu nity-durin g-home-care-and-in-healt hcare -setti ngsin-the-conte xt-of-the-novel Advice on the use of masks for children in the community in the context of COVID-19: annex to the advice on the use of masks in the context of COVID-19 Physiology at a Glance. 3 Die Atemregulation (The breathing regulation) Fact check: Three children have not died from wearing masks in Germany. Reuters Facial masks in children: the position statement of the Italian pediatric society SARS-CoV-2 pandemic: Should children wear masks Addressing the consequences of school closure due to COVID-19 on children's physical and mental wellbeing The long term distributional and welfare effects of Covid-19 school closures. 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