Author Contributions: Conceptualization, K.K., S.W., O.H., B.K.; A.P.; methodology, K.K., S.W., O.H., B.K. and A.P.; software, K.K., O.H.; formal analysis, K.K., S.W. O.H., B.K., A.P.; investigation, K.K., S.W., O.H.,B.K. A.P.; writing—original draft preparation, K.K., S.W., O.H., B.K.,A.P.; writing—review and editing K.K., S.W., O.H., B.K. and A.P. All authors have read and agreed to the published version of the manuscript.
Funding: This research received no external funding.
Conflict of Interest: The authors declare no conflict of interest.
Institutional ethics board committee approval: not applicable.
Literature
1. Li Y, Liang M, Gao L, et al. Face masks to prevent transmission of COVID-19: A systematic review and meta-analysis. Am J Infect Control. 2021;49(7):900-906. doi:10.1016/j.ajic.2020.12.007
2. Howard J, Huang A, Li Z, et al. An evidence review of face masks against COVID-19. PNAS. 2021;118(4). doi:10.1073/pnas.2014564118
3. Bundgaard H, Bundgaard JS, Raaschou-Pedersen DET, et al. Effectiveness of Adding a Mask Recommendation to Other Public Health Measures to Prevent SARS-CoV-2 Infection in Danish Mask Wearers. Ann Intern Med. Published online November 18, 2020. doi:10.7326/M20-6817
4. Gettings J. Mask Use and Ventilation Improvements to Reduce COVID-19 Incidence in Elementary Schools — Georgia, November 16–December 11, 2020. MMWR Morb Mortal Wkly Rep. 2021;70. doi:10.15585/mmwr.mm7021e1
5. Guerra D, Guerra DJ. Mask mandate and use efficacy for COVID-19 containment in US States. International Research Journal of Public Health. 20210824;5. doi:10.28933/irjph-2021-08-1005
6. Fisher KA, Tenforde MW, Feldstein LR, et al. Community and close contact exposures associated with COVID-19 among symptomatic adults ≥18 years in 11 outpatient health care facilities - United States, July 2020. MMWR Morbidity and mortality weekly report. 2020;69(36):1258-1264. doi:10.15585/mmwr.mm6936a5
7. Jefferson T, Mar CBD, Dooley L, et al. Physical interventions to interrupt or reduce the spread of respiratory viruses. Cochrane Database of Systematic Reviews. 2020;(11). doi:10.1002/14651858.CD006207.pub5
8. Fønhus MS, Dalsbø TK, Brurberg KG. Facemasks to Prevent Transmission of Respiratory Illness, Such as COVID-19. Norwegian Institute of Public Health; 2021. Accessed November 7, 2021. https://fhi.brage.unit.no/fhi-xmlui/handle/11250/2756758
9. Heneghan CJ, Spencer EA, Brassey J, et al. SARS-CoV-2 and the role of orofecal transmission: a systematic review. Published online November 2, 2021. doi:10.12688/f1000research.51592.2
10. Boretti A. Efficacy of Generalized Face Masking Mandates. Health Services Research and Managerial Epidemiology. January 2021. doi:10.1177/23333928211058023
11. Kisielinski K, Giboni P, Prescher A, et al. Is a Mask That Covers the Mouth and Nose Free from Undesirable Side Effects in Everyday Use and Free of Potential Hazards? International Journal of Environmental Research and Public Health. 2021;18(8):4344. doi:10.3390/ijerph18084344
12. Kappstein I. Mund-Nasen-Schutz in der Öffentlichkeit: Keine Hinweise für eine Wirksamkeit. Krankenhaushygiene up2date. 2020;15(3):279-295. doi:10.1055/a-1174-6591
13. Gralton, J.; McLaws, M.-L. Protecting Healthcare Workers from Pandemic Influenza: N95 or Surgical Masks? Crit. Care Med. 201038, 657–667
14. Faustman EM, Silbernagel SM, Fenske RA, Burbacher TM, Ponce RA. Mechanisms underlying Children's susceptibility to environmental toxicants. Environ Health Perspect. 2000;108 Suppl 1(Suppl 1):13-21. doi:10.1289/ehp.00108s113
15. Azuma K, Kagi N, Yanagi U, Osawa H. Effects of low-level inhalation exposure to carbon dioxide in indoor environments: A short review on human health and psychomotor performance. Environment International. 2018;121:51-56. doi:10.1016/j.envint.2018.08.059
16. Guais A, Brand G, Jacquot L, et al. Toxicity of Carbon Dioxide: A Review. Chem Res Toxicol. 2011;24(12):2061-2070. doi:10.1021/tx200220r
17. https://www.cdc.gov/niosh/npg/npgd0103.html
18. Butz U. Rückatmung von Kohlendioxid bei Verwendung von Operationsmasken als hygienischer Mundschutz an medizinischem Fachpersonal. Published online 2005.
19. Pifarré F, Zabala DD, Grazioli G, de Yzaguirre i Maura I. COVID 19 and mask in sports. Apunts Sports Medicine. Published online June 6, 2020. doi:10.1016/j.apunsm.2020.06.002
20. Blad T, Nijssen J, Broeren F, et al. A Rapidly Deployable Test Suite for Respiratory Protective Devices in the COVID-19 Pandemic. Applied Biosafety. 2020;25(3):161-168. doi:10.1177/1535676020947284
21. Salati H, Khamooshi M, Vahaji S, Christo FC, Fletcher DF, Inthavong K. N95 respirator mask breathing leads to excessive carbon dioxide inhalation and reduced heat transfer in a human nasal cavity. Phys Fluids (1994). 2021;33(8):081913. doi:10.1063/5.0061574
22. Zhang X, Li H, Shen S, Cai M. Investigation of the flow-field in the upper respiratory system when wearing N95 filtering facepiece respirator. J Occup Environ Hyg. 2016;13(5):372-382. doi:10.1080/15459624.2015.1116697
23. Sinkule EJ, Powell JB, Goss FL. Evaluation of N95 respirator use with a surgical mask cover: effects on breathing resistance and inhaled carbon dioxide. Ann Occup Hyg. 2013;57(3):384-398. doi:10.1093/annhyg/mes068
24. Laferty EA, McKay RT. Physiologic effects and measurement of carbon dioxide and oxygen levels during qualitative respirator fit testing. J Chem Health Saf. 2006;13(5):22-28. doi:10.1016/j.jchas.2005.11.015
25. Roberge RJ, Coca A, Williams WJ, Powell JB, Palmiero AJ. Physiological impact of the N95 filtering facepiece respirator on healthcare workers. Respir Care. 2010;55(5):569-577.
26. Geiss, O. (2021). Effect of Wearing Face Masks on the Carbon Dioxide Concentration in the Breathing Zone. Aerosol Air Qual. Res. 21, 200403.
27. Rhee MSM, Lindquist CD, Silvestrini MT, Chan AC, Ong JJY, Sharma VK. Carbon dioxide increases with face masks but remains below short-term NIOSH limits. BMC Infect Dis. 2021 Apr 16;21(1):354. doi: 10.1186/s12879-021-06056-0. PMID: 33858372; PMCID: PMC8049746.
28. Ellingsen I, Sydnes G, Hauge A, Zwart JA, Liestøl K, Nicolaysen G. CO2 sensitivity in humans breathing 1 or 2% CO2 in air. Acta Physiologica Scandinavica. 1987;129(2):195-202. doi:10.1111/j.1748-1716.1987.tb08059.x
29. Fantin R. The effect of wearing an FFP3 mask (3M TM Aura TM ) with an exhalation valve on gas exchange in medical staff. Int J Occup Med Environ Health. Published online April 23, 2021. doi:10.13075/ijomeh.1896.01809
30. Bharatendu C, Ong JJY, Goh Y, et al. Powered Air Purifying Respirator (PAPR) restores the N95 face mask induced cerebral hemodynamic alterations among Healthcare Workers during COVID-19 Outbreak. J Neurol Sci. 2020;417:117078. doi:10.1016/j.jns.2020.117078
31. Epstein D, Korytny A, Isenberg Y, et al. Return to training in the COVID-19 era: The physiological effects of face masks during exercise. Scandinavian Journal of Medicine & Science in Sports. 2020;n/a(n/a). doi:10.1111/sms.13832
32. Georgi C, Haase-Fielitz A, Meretz D, Gäsert L, Butter C. Einfluss gängiger Gesichtsmasken auf physiologische Parameter und Belastungsempfinden unter arbeitstypischer körperlicher Anstrengung. Deutsches Ärzteblatt. 2020;(117):674-675. doi:DOI: 10.3238/arztebl.2020.0674
33. Kyung SY, Kim Y, Hwang H, Park JW, Jeong SH. Risks of N95 Face Mask Use in Subjects With COPD. Respir Care. 2020;65(5):658-664. doi:10.4187/respcare.06713
34. Mo Y. Risk and impact of using mask on COPD patients with acute exacerbation during the COVID-19 outbreak: a retrospective study. Published online July 16, 2020. doi:10.21203/rs.3.rs-39747/v1
35. Rebmann T, Carrico R, Wang J. Physiologic and other effects and compliance with long-term respirator use among medical intensive care unit nurses. Am J Infect Control. 2013;41(12):1218-1223. doi:10.1016/j.ajic.2013.02.017
36. Roberge RJ, Kim JH, Benson SM. Absence of consequential changes in physiological, thermal and subjective responses from wearing a surgical mask. Respiratory Physiology & Neurobiology. 2012;181(1):29-35. doi:10.1016/j.resp.2012.01.010
37. Roberge RJ, Kim JH, Powell JB. N95 respirator use during advanced pregnancy. Am J Infect Control. 2014;42(10):1097-1100. doi:10.1016/j.ajic.2014.06.025
38. Tong PSY, Kale AS, Ng K, et al. Respiratory consequences of N95-type Mask usage in pregnant healthcare workers—a controlled clinical study. Antimicrobial Resistance & Infection Control. 2015;4(1):48. doi:10.1186/s13756-015-0086-z
39. Lubrano R, Bloise S, Marcellino A, et al. Effects of N95 Mask Use on Pulmonary Function in Children. J Pediatr. 2021;237:143-147. doi:10.1016/j.jpeds.2021.05.050
40. Zhang G, Li M, Zheng M, et al. Effect of Surgical Masks on Cardiopulmonary Function in Healthy Young Subjects: A Crossover Study. Front Physiol. 2021;12:710573. doi:10.3389/fphys.2021.710573
41. Mapelli M, Salvioni E, Martino FD, et al. “You can leave your mask on”: effects on cardiopulmonary parameters of different airway protection masks at rest and during maximal exercise. European Respiratory Journal. Published online January 1, 2021. doi:10.1183/13993003.04473-2020
42. Dirol H, Alkan E, Sindel M, Ozdemir T, Erbas D. The physiological and disturbing effects of surgical face masks in the COVID-19 era. BLL. 2021;122(11):821-825. doi:10.4149/BLL_2021_131
43. Kim JH, Benson SM, Roberge RJ. Pulmonary and heart rate responses to wearing N95 filtering facepiece respirators. Am J Infect Control. 2013;41(1):24-27. doi:10.1016/j.ajic.2012.02.037
44. Sukul P, Bartels J, Fuchs P, et al. Adverse effects of COVID-protective face-masks and wearing durations onto respiratory-haemodynamic physiology and exhaled breath constituents. Published online December 5, 2021. doi:10.21203/rs.3.rs-930030/v1
45. Shein SL, Whitticar S, Mascho KK, Pace E, Speicher R, Deakins K. The effects of wearing facemasks on oxygenation and ventilation at rest and during physical activity. PLoS One. 2021;16(2):e0247414. doi:10.1371/journal.pone.0247414
46. Jafari E, Togha M, Kazemizadeh H, et al. Evaluation of headache associated with personal protective equipment during COVID-19. Brain and Behavior. n/a(n/a):e2435. doi:10.1002/brb3.2435
47. Doherty CJ, Mann LM, Angus SA, Chan JS, Molgat-Seon Y, Dominelli PB. Impact of wearing a surgical and cloth mask during cycle exercise. Appl Physiol Nutr Metab. 2021;46(7):753-762. doi:10.1139/apnm-2021-0190
48. Lubrano R, Bloise S, Testa A, et al. Assessment of Respiratory Function in Infants and Young Children Wearing Face Masks During the COVID-19 Pandemic. JAMA Netw Open. 2021;4(3):e210414. doi:10.1001/jamanetworkopen.2021.0414
49. Kim JH, Wu T, Powell JB, Roberge RJ. Physiologic and fit factor profiles of N95 and P100 filtering facepiece respirators for use in hot, humid environments. Am J Infect Control. 2016;44(2):194-198. doi:10.1016/j.ajic.2015.08.027
50. Schaefer KE. Respiratory adaptation to chronic hypercapnia. Ann N Y Acad Sci. 1963;109:772-782. doi:10.1111/j.1749-6632.1963.tb13505.x
51. Langford NJ. Carbon Dioxide Poisoning. Toxicol Rev. 2005;24(4):229-235. doi: 10.2165/00139709-200524040-00003.
52. Rozman KK, Doull J. Dose and time as variables of toxicity. Toxicology. 2000;144(1):169-178. doi:10.1016/S0300-483X(99)00204-8
53. Rozman KK. The role of time in toxicology or Haber’s c×t product. Toxicology. 2000;149(1):35-42.
doi:10.1016/S0300-483X(00)00230-4
54. Górska K, Korczyński P, Maskey-Warzęchowska M, Chazan R, Krenke R. Variability of Transcutaneous Oxygen and Carbon Dioxide Pressure Measurements Associated with Sensor Location. Adv Exp Med Biol. 2015;858:39-46. doi:10.1007/5584_2015_126
55. Razi E, Moosavi GA, Omidi K, Khakpour Saebi A, Razi A. Correlation of end-tidal carbon dioxide with arterial carbon dioxide in mechanically ventilated patients. Arch Trauma Res. 2012;1(2):58-62. doi:10.5812/atr.6444
56. Contini M, Angelucci A, Aliverti A, et al. Comparison between PtCO2 and PaCO2 and Derived Parameters in Heart Failure Patients during Exercise: A Preliminary Study. Sensors. 2021;21(19):6666. doi:10.3390/s21196666
57. Wirth, W; Gloxhuber, C: Toxikologie (Georg Thieme Stuttgart New York, 3rd ed. 1981, p. 156
58. Evaluation of the Health Aspects of Carbon Dioxide as a Food Ingredient. Federation of American Societies for Experimental Biology, Bethesda, MD. Life Sciences Research Office.; Food and Drug Administration, Washington, DC. Bureau of Foods.; 1979. Accessed November 7, 2021. https://ntrl.ntis.gov/NTRL/dashboard/searchResults/titleDetail/PB80104615.xhtml
59. Howard WR, Wong B, Okolica M, Bynum KS, James RA. The Prenatal Development Effects of Carbon Dioxide (CO2) Exposure in Rats (Rattus Norvegicus): Defense Technical Information Center; 2012. doi:10.21236/ADA583166
60. Howard WR, Wong B, Yeager KSB, et al. Submarine exposure guideline recommendations for carbon dioxide based on the prenatal developmental effects of exposure in rats. Birth Defects Res. 2019;111(1):26-33. doi:10.1002/bdr2.1417
61. Burton RF. Intracellular buffering. Respiration Physiology. 1978;33(1):51-58. doi:10.1016/0034-5687(78)90083-X
62. Eckenhoff RG, Longnecker DE. Goodman and Gilman’s The Pharmacological Basis of Therapeutics, 9th ed. | Sigma-Aldrich, (Hardman JG,ed). McGraw Hill, 355-356. Accessed November 7, 2021. http://www.sigmaaldrich.com/
63. Schaefer KE, Pasquale SM, Messier AA, Niemoeller H. CO2-induced kidney calcification. Undersea Biomed Res. 1979;6 Suppl:S143-153.
64. Adeva-Andany MM, Carneiro-Freire N, Donapetry-García C, Rañal-Muíño E, López-Pereiro Y. The Importance of the Ionic Product for Water to Understand the Physiology of the Acid-Base Balance in Humans. BioMed Research International. 2014;2014:e695281. doi:10.1155/2014/695281
65. Adeva-Andany MM, Fernández-Fernández C, Sánchez-Bello R, Donapetry-García C, Martínez-Rodríguez J. The role of carbonic anhydrase in the pathogenesis of vascular calcification in humans. Atherosclerosis. 2015;241(1):183-191. doi:10.1016/j.atherosclerosis.2015.05.012
66. Kim IG, Jo BH, Kang DG, Kim CS, Choi YS, Cha HJ. Biomineralization-based conversion of carbon dioxide to calcium carbonate using recombinant carbonic anhydrase. Chemosphere. 2012;87(10):1091-1096. doi:10.1016/j.chemosphere.2012.02.003
67. Tan SI, Han YL, Yu YJ, et al. Efficient carbon dioxide sequestration by using recombinant carbonic anhydrase. Process Biochemistry. 2018;73:38-46. doi:10.1016/j.procbio.2018.08.017
68. Schaefer KE, Douglas WH, Messier AA, Shea ML, Gohman PA. Effect of prolonged exposure to 0.5% CO2 on kidney calcification and ultrastructure of lungs. Undersea Biomed Res. 1979;6 Suppl:S155-161.
69. Wallingford MC, Benson C, Chavkin NW, Chin MT, Frasch MG. Placental Vascular Calcification and Cardiovascular Health: It Is Time to Determine How Much of Maternal and Offspring Health Is Written in Stone. Frontiers in Physiology. 2018;9:1044. doi:10.3389/fphys.2018.01044
70. Chen KH, Chen LR, Lee YH. Exploring the relationship between preterm placental calcification and adverse maternal and fetal outcome. Ultrasound in Obstetrics & Gynecology. 2011;37(3):328-334. doi:10.1002/uog.7733
71. Chen KH, Seow KM, Chen LR. The role of preterm placental calcification on assessing risks of stillbirth. Placenta. 2015;36(9):1039-1044. doi:10.1016/j.placenta.2015.06.015
72. Ezraty B, Chabalier M, Ducret A, Maisonneuve E, Dukan S. CO2 exacerbates oxygen toxicity. EMBO reports. 2011;12(4):321-326. doi:10.1038/embor.2011.7
73. Thom SR, Bhopale VM, Hu J, Yang M. Inflammatory responses to acute elevations of carbon dioxide in mice. Journal of Applied Physiology. 2017;123(2):297-302. doi:10.1152/japplphysiol.00343.2017
74. Beheshti A, Cekanaviciute E, Smith DJ, Costes SV. Global transcriptomic analysis suggests carbon dioxide as an environmental stressor in spaceflight: A systems biology GeneLab case study. Sci Rep. 2018;8(1):4191. doi:10.1038/s41598-018-22613-1
75. Zappulla D. Environmental Stress, Erythrocyte Dysfunctions, Inflammation, and the Metabolic Syndrome: Adaptations to CO2 Increases? Journal of the CardioMetabolic Syndrome. 2008;3(1):30-34. doi:10.1111/j.1559-4572.2008.07263.x
76. Jacobson TA, Kler JS, Hernke MT, Braun RK, Meyer KC, Funk WE. Direct human health risks of increased atmospheric carbon dioxide. Nat Sustain. 2019;2(8):691-701. doi:10.1038/s41893-019-0323-1
77. Kiray M, Sisman AR, Camsari UM, et al. Effects of carbon dioxide exposure on early brain development in rats. Biotechnic & Histochemistry. 2014;89(5):371-383. doi:10.3109/10520295.2013.872298
78. Veselá A, Wilhelm J. The role of carbon dioxide in free radical reactions of the organism. Physiol Res. 2002;51(4):335-339.
79. Forrest VJ, Kang YH, McClain DE, Robinson DH, Ramakrishnan N. Oxidative stress-induced apoptosis prevented by Trolox. Free Radic Biol Med. 1994;16(6):675-684. doi:10.1016/0891-5849(94)90182-1
80. Leon J, Acuña-Castroviejo D, Sainz RM, Mayo JC, Tan DX, Reiter RJ. Melatonin and mitochondrial function. Life Sci. 2004;75(7):765-790. doi:10.1016/j.lfs.2004.03.003
81. Uysal N, Kiray M, Sisman AR, et al. Effects of exercise and poor indoor air quality on learning, memory and blood IGF-1 in adolescent mice. Biotechnic & Histochemistry. 2014;89(2):126-135. doi:10.3109/10520295.2013.825318
82. Wine RN, McPherson CA, Harry GJ. IGF-1 and pAKT Signaling Promote Hippocampal CA1 Neuronal Survival Following Injury to Dentate Granule Cells. Neurotox Res. 2009;16(3):280-292. doi:10.1007/s12640-009-9060-y
83. Aksu I, Ates M, Baykara B, et al. Anxiety correlates to decreased blood and prefrontal cortex IGF-1 levels in streptozotocin induced diabetes. Neurosci Lett. 2012;531(2):176-181. doi:10.1016/j.neulet.2012.10.045
84. Aksu I, Baykara B, Kiray M, et al. Serum IGF-1 levels correlate negatively to liver damage in diabetic rats. Biotechnic & Histochemistry. 2013;88(3-4):194-201. doi:10.3109/10520295.2012.758311
85. Uysal N, Tugyan K, Kayatekin BM, et al. The effects of regular aerobic exercise in adolescent period on hippocampal neuron density, apoptosis and spatial memory. Neuroscience Letters. 2005;383(3):241-245. doi:10.1016/j.neulet.2005.04.054
86. Uysal N, Gonenc S, Acikgoz O, et al. Age-dependent effects of maternal deprivation on oxidative stress in infant rat brain. Neurosci Lett. 2005;384(1-2):98-101. doi:10.1016/j.neulet.2005.04.052
87. Uysal N, Sisman AR, Dayi A, et al. Acute footshock-stress increases spatial learning-memory and correlates to increased hippocampal BDNF and VEGF and cell numbers in adolescent male and female rats. Neurosci Lett. 2012;514(2):141-146. doi:10.1016/j.neulet.2012.02.049
88. Tugyan K, Uysal N, Ozdemir D, et al. Protective effect of melatonin against maternal deprivation-induced acute hippocampal damage in infant rats. Neurosci Lett. 2006;398(1-2):145-150. doi:10.1016/j.neulet.2005.12.090
89. Sikter A, Faludi G, Rihmer Z. The role of carbon dioxide (and intracellular pH) in the pathomechanism of several mental disorders. Are the diseases of civilization caused by learnt behaviour, not the stress itself? Neuropsychopharmacol Hung. 2009;11(3):161-173.
90. Hoffman WE, Charbel FT, Edelman G, Ausman JI. Brain tissue acid-base response to hypercapnia in neurosurgical patients. Neurol Res. 1995 Dec;17(6):417-20. PMID: 8622793
91. Huo XL, Min JJ, Pan CY, et al. Efficacy of lovastatin on learning and memory deficits caused by chronic intermittent hypoxia-hypercapnia: through regulation of NR2B-containing NMDA receptor-ERK pathway. PLoS One. 2014;9(4):e94278. Published 2014 Apr 9. doi:10.1371/journal.pone.0094278
92. Dodge FA, Rahamimoff R. Co-operative action a calcium ions in transmitter release at the neuromuscular junction. J Physiol. 1967;193(2):419-432. doi:10.1113/jphysiol.1967.sp008367
93. Tombaugh GC, Somjen GG. Differential sensitivity to intracellular pH among high- and low-threshold Ca2+ currents in isolated rat CA1 neurons. J Neurophysiol. 1997;77(2):639-653. doi:10.1152/jn.1997.77.2.639
94. Hota KB, Hota SK, Chaurasia OP, Singh SB. Acetyl-L-carnitine-mediated neuroprotection during hypoxia is attributed to ERK1/2-Nrf2-regulated mitochondrial biosynthesis. Hippocampus. 2012;22(4):723-736. doi:10.1002/hipo.20934
95. Vandemark NL, Schanbacher BD, Gomes WR. Alterations in testes of rats exposed to elevated atmospheric carbon dioxide. Reproduction. 1972;28(3):457-459. doi:10.1530/jrf.0.0280457
96. National Research Council. Standing Operating Procedures for Developing Acute Exposure Guideline Levels for Hazardous Chemicals. The National Academies Press; 2001. doi:10.17226/10122
97. Safety Data Sheets. Linde Industrial Gases. Accessed May 13, 2021. http://www.gas.linde.co.th/en/sheq/product_and_process_safety_information/safety_data_sheets/index.html
98. What Countries Require or Recommend Masks In Public? #Masks4All. Published April 23, 2020. Accessed November 7, 2021. https://masks4all.co/what-countries-require-masks-in-public/
99. Chmielewska B, Barratt I, Townsend R, et al. Effects of the COVID-19 pandemic on maternal and perinatal outcomes: a systematic review and meta-analysis. The Lancet Global Health. 2021;0(0). doi:10.1016/S2214-109X(21)00079-6
100. Flaherman VJ, Afshar Y, Boscardin WJ, et al. Infant Outcomes Following Maternal Infection With Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2): First Report From the Pregnancy Coronavirus Outcomes Registry (PRIORITY) Study. Clinical Infectious Diseases. 2020;(ciaa1411). doi:10.1093/cid/ciaa1411
101 DeSisto, Carla L. Risk for Stillbirth Among Women With and Without COVID-19 at Delivery Hospitalization—United States, March 2020–September 2021. MMWR. Morbidity and mortality weekly report 70 (2021)
102 Hui L, Marzan MB, Potenza S, et al. Increase in Preterm Stillbirths and Reduction in Iatrogenic Preterm Births for Fetal Compromise: A Multi-Centre Cohort Study of COVID-19 Lockdown Effects in Melbourne, Australia.; 2021:2021.10.04.21264500. doi:10.1101/2021.10.04.21264500
103. Rangel EL, Castillo-Angeles M, Easter SR, et al. Incidence of Infertility and Pregnancy Complications in US Female Surgeons. JAMA Surg. 2021;156(10):905-915. doi:10.1001/jamasurg.2021.3301
104. Curtis MD, Villani L, Polo A. Increase of stillbirth and decrease of late preterm infants during the COVID-19 pandemic lockdown. Archives of Disease in Childhood - Fetal and Neonatal Edition. 2021;106(4):456-456. doi:10.1136/archdischild-2020-320682
105. Vaccaro C, Mahmoud F, Aboulatta L, Aloud B, Eltonsy S. The impact of COVID-19 first wave national lockdowns on perinatal outcomes: a rapid review and meta-analysis. BMC Pregnancy and Childbirth. 2021;21(1):676. doi:10.1186/s12884-021-04156-y
106. Pasternak B, Neovius M, Söderling J, et al. Preterm Birth and Stillbirth During the COVID-19 Pandemic in Sweden: A Nationwide Cohort Study. Ann Intern Med. 2021;174(6):873-875. doi:10.7326/M20-6367
107. Toprak E, Bulut AN. The effect of mask use on maternal oxygen saturation in term pregnancies during the COVID-19 process. Journal of Perinatal Medicine. 2021;49(2):148-152. doi:10.1515/jpm-2020-0422
108. Deoni SC, Beauchemin J, Volpe A, D’Sa V, Consortium the R. Impact of the COVID-19 Pandemic on Early Child Cognitive Development: Initial Findings in a Longitudinal Observational Study of Child Health.; 2021:2021.08.10.21261846. doi:10.1101/2021.08.10.21261846
109. MPG - nichtamtliches Inhaltsverzeichnis. Accessed June 6, 2021. https://www.gesetze-im-internet.de/mpg/
110. REGULATION (EU) 2017/745 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 5 April 2017 on medical devices, amending Directive 2001/83/EC, Regulation (EC) No 178/2002 and Regulation (EC) No 1223/2009 and repealing Council Directives 90/385/EEC and 93/42/EECL_2017117EN.01000101.xml. Accessed June 6, 2021. https://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELEX:32017R0745&from=DE.
111. Organization WH. WHO - Advice on the use of masks in the context of COVID-19: interim guidance, 1 December 2020. Published online 2020. Accessed June 6, 2021. htps://apps.who.int/iris/handle/10665/337199.
112. Cao S, Gan Y, Wang C, et al. Post-lockdown SARS-CoV-2 nucleic acid screening in nearly ten million residents of Wuhan, China. Nat Commun. 2020;11(1):5917. doi:10.1038/s41467-020-19802-w
113. Obi OC, Odoh DA. Transmission of Coronavirus (SARS-CoV-2) by Presymptomatic and Asymptomatic COVID-19 Carriers: A Systematic Review. EUROPEAN J MED ED TE. 2021;14(3):em2110. doi:10.30935/ejmets/11060
114. Jefferson T, Spencer EA, Brassey J, et al. Transmission of Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) from pre and asymptomatic infected individuals. A systematic review. Clinical Microbiology and Infection. Published online October 29, 2021. doi:10.1016/j.cmi.2021.10.015
115. Qiu X, Nergiz AI, Maraolo AE, Bogoch II, Low N, Cevik M. The role of asymptomatic and pre-symptomatic infection in SARS-CoV-2 transmission—a living systematic review. Clinical Microbiology and Infection. 2021;27(4):511-519. doi:10.1016/j.cmi.2021.01.011
116. Savvides C, Siegel R. Asymptomatic and presymptomatic transmission of SARS-CoV-2: A systematic review. medRxiv. doi:10.1101/2020.06.11.201290727
117. Streeck H, Schulte B, Kuemmerer B, et al. Infection fatality rate of SARS-CoV-2 infection in a German community with a super-spreading event. medRxiv. Published online June 2, 2020:2020.05.04.20090076. doi:10.1101/2020.05.04.20090076
118. Ioannidis J. The infection fatality rate of COVID-19 inferred from seroprevalence data. medRxiv. Published online July 14, 2020:2020.05.13.20101253. doi:10.1101/2020.05.13.20101253
119. Ioannidis JPA. Reconciling estimates of global spread and infection fatality rates of COVID-19: An overview of systematic evaluations. Eur J Clin Invest. 2021;51(5):e13554. doi:10.1111/eci.13554
120. Bagus P, Peña-Ramos JA, Sánchez-Bayón A. COVID-19 and the Political Economy of Mass Hysteria. International Journal of Environmental Research and Public Health. 2021;18(4):1376. doi:10.3390/ijerph180413768.
121. Sorg A, Hufnagel M, Doenhardt M, et al. Risk of Hospitalization, severe disease, and mortality due to COVID-19 and PIMS-TS in children with SARS-CoV-2 infection in Germany. medRxiv; 2021. DOI: 10.1101/2021.11.30.21267048.
122. Karnauskas, K. B., Miller, S. L., & Schapiro, A. C. (2020). Fossil fuel combustion is driving indoor CO2 toward levels harmful to human cognition. GeoHealth, 4(5), e2019GH000237.
123. Duarte, C. M., Jaremko, Ł., & Jaremko, M. (2020). Hypothesis: Potentially Systemic Impacts of Elevated CO2 on the Human Proteome and Health. Frontiers in public health, 8, 645.
124. Bayati M, Vu DC, Vo PH, et al. Health risk assessment of volatile organic compounds at daycare facilities. Indoor Air. 2021;31(4):977-988. doi:10.1111/ina.12801
125. Kerkeling S, Sandten C, Schupp T, Kreyenschmidt M. VOC emissions from particle filtering half masks – methods, risks and need for further action. EXCLI Journal. 2021;20:995-1008. doi:10.17179/excli2021-3734
126. Töndury, G. (1958). Entwicklungsgeschichte und Fehlbildungen der Wirbelsäule (Vol. 7). Hippokrates-Verlag
127. Meessen, H. (1948). Chronic Carbon Dioxide Poisoning. Experimental Studies. Arch. Pathol., 45(1), 36-40]
128. WMA - The World Medical Association-Declaration of Helsinki. Accessed November 8, 2021. https://www.wma.net/what-we-do/medical-ethics/declaration-of-helsinki/
129. WMA - The World Medical Association-WMA Declaration of Lisbon on the Rights of the Patient. Accessed November 8, 2021. https://www.wma.net/policies-post/wma-declaration-of-lisbon-on-the-rights-of-the-patient/
130. Nuremberg Code. United States Holocaust Memorial Museum. Accessed November 8, 2021. https://www.ushmm.org/information/exhibitions/online-exhibitions/special-focus/doctors-trial/nuremberg-code