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Meta-analyses and single-site studies have established that children are less infectious than adults within a household when positive for ancestral SARS-CoV-2. In addition, children appear less susceptible to infection when exposed to ancestral SARS-CoV-2 within a household. The emergence of SARS-CoV-2 variants of concern (VOC) has been associated with an increased number of paediatric infections worldwide. However, the role of children in the household transmission of VOC, relative to the ancestral virus, remains unclear.


We aimed to evaluate children's role in household transmission of SARS-CoV-2 VOC.


We perform a meta-analysis of the role of children in household transmission of both ancestral SARS-CoV-2 and SARS-CoV-2 VOC.


Unlike with the ancestral virus, children infected with VOC spread SARS-CoV-2 to an equivalent number of household contacts as infected adults and were equally as likely to acquire SARS-CoV-2 VOC from an infected family member. Interestingly, the same was observed when unvaccinated children exposed to VOC were compared with unvaccinated adults exposed to VOC.


These data suggest that the emergence of VOC was associated with a fundamental shift in the epidemiology of SARS-CoV-2. It is unlikely that this is solely the result of age-dependent differences in vaccination during the VOC period and may instead reflect virus evolution over the course of the pandemic.


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  1. Zhu Y, Bloxham CJ, Hulme KD, Sinclair JE, Tong ZWM, Steele LE, et al. A meta-analysis on the role of children in severe acute respiratory syndrome coronavirus 2 in household transmission clusters. Clin Infect Dis. 2021;72(12):e1146-53.  https://doi.org/10.1093/cid/ciaa1825  PMID: 33283240 
  2. Goldstein E, Lipsitch M, Cevik M. On the effect of age on the transmission of SARS-CoV-2 in households, schools, and the community. J Infect Dis. 2021;223(3):362-9.  https://doi.org/10.1093/infdis/jiaa691  PMID: 33119738 
  3. Koelle K, Martin MA, Antia R, Lopman B, Dean NE. The changing epidemiology of SARS-CoV-2. Science. 2022;375(6585):1116-21.  https://doi.org/10.1126/science.abm4915  PMID: 35271324 
  4. Schumm L, Blankenburg J, Kahre E, Armann J, Dalpke AH, Lück C, et al. Lower SARS-CoV-2 household transmission in children and adolescents compared to adults. Sci Rep. 2022;12(1):22453.  https://doi.org/10.1038/s41598-022-24643-2  PMID: 36575230 
  5. Hodcroft E. Overview of variants in countries. Bern: Institute of Social and Preventive Medicine. [Accessed: 30 Oct 2022]. Available from: https://covariants.org/per-country
  6. Ng OT, Koh V, Chiew CJ, Marimuthu K, Thevasagayam NM, Mak TM, et al. Impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination and pediatric age on delta variant household transmission. Clin Infect Dis. 2022;75(1):e35-43.  https://doi.org/10.1093/cid/ciac219  PMID: 35323887 
  7. Baker JM, Nakayama JY, O’Hegarty M, McGowan A, Teran RA, Bart SM, et al. SARS-CoV-2 B.1.1.529 (Omicron) variant transmission within households - four U.S. jurisdictions, November 2021-February 2022. MMWR Morb Mortal Wkly Rep. 2022;71(9):341-6.  https://doi.org/10.15585/mmwr.mm7109e1  PMID: 35238860 
  8. Chen F, Tian Y, Zhang L, Shi Y. The role of children in household transmission of COVID-19: a systematic review and meta-analysis. Int J Infect Dis. 2022;122:266-75.  https://doi.org/10.1016/j.ijid.2022.05.016  PMID: 35562045 
  9. Waltenburg MA, Whaley MJ, Chancey RJ, Donnelly MAP, Chuey MR, Soto R, et al. Household transmission and symptomology of severe acute respiratory syndrome coronavirus 2 alpha variant among children-California and Colorado, 2021. J Pediatr. 2022;247:29-37.e7.  https://doi.org/10.1016/j.jpeds.2022.04.032  PMID: 35447121 
  10. Knol MJ, Backer JA, de Melker HE, van den Hof S, Gier B. Transmissibility of SARS-CoV-2 among fully vaccinated individuals. Lancet Infect Dis. 2022;22(1):16-7.  https://doi.org/10.1016/S1473-3099(21)00763-5  PMID: 34953541 
  11. European Medicines Agency (EMA). Comirnaty COVID-19 vaccine: EMA recommends approval for children aged 5 to 11. Amsterdam: EMA; 2021. Available from: https://www.ema.europa.eu/en/news/comirnaty-covid-19-vaccine-ema-recommends-approval-children-aged-5-11
  12. Howard-Jones AR, Bowen AC, Danchin M, Koirala A, Sharma K, Yeoh DK, et al. COVID-19 in children: I. Epidemiology, prevention and indirect impacts. J Paediatr Child Health. 2022;58(1):39-45.  https://doi.org/10.1111/jpc.15791  PMID: 34643307 
  13. Prunas O, Warren JL, Crawford FW, Gazit S, Patalon T, Weinberger DM, et al. Vaccination with BNT162b2 reduces transmission of SARS-CoV-2 to household contacts in Israel. Science. 2022;375(6585):1151-4.  https://doi.org/10.1126/science.abl4292  PMID: 35084937 
  14. World Health Organization (WHO). Household transmission investigation protocol for 2019-novel coronavirus (COVID-19) infection. Geneva: WHO; 2020. Available from: https://www.who.int/publications/i/item/household-transmission-investigation-protocol-for-2019-novel-coronavirus-(2019-ncov)-infection
  15. Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;6(7):e1000097.  https://doi.org/10.1371/journal.pmed.1000097  PMID: 19621072 
  16. Lin L, Chu H. Meta-analysis of proportions using generalized linear mixed models. Epidemiology. 2020;31(5):713-7.  https://doi.org/10.1097/EDE.0000000000001232  PMID: 32657954 
  17. Sordo AA, Dunn A, Gardiner ER, Reinten TA, Tsang TS, Deng L, et al. Household transmission of COVID-19 in 2020 in New South Wales, Australia. Commun Dis Intell (2018). 2022;46:46.  https://doi.org/10.33321/cdi.2022.46.16  PMID: 35469559 
  18. Musa S, Kissling E, Valenciano M, Dizdar F, Blažević M, Jogunčić A, et al. Household transmission of SARS-CoV-2: a prospective observational study in Bosnia and Herzegovina, August-December 2020. Int J Infect Dis. 2021;112:352-61.  https://doi.org/10.1016/j.ijid.2021.09.063  PMID: 34600136 
  19. Afonso ET, Marques SM, Costa LDC, Fortes PM, Peixoto F, Bichuetti-Silva DC, et al. Secondary household transmission of SARS-CoV-2 among children and adolescents: Clinical and epidemiological aspects. Pediatr Pulmonol. 2022;57(1):162-75.  https://doi.org/10.1002/ppul.25711  PMID: 34590794 
  20. Wilkinson K, Chen X, Shaw S. Secondary attack rate of COVID-19 in household contacts in the Winnipeg Health Region, Canada. Can J Public Health. 2021;112(1):12-6.  https://doi.org/10.17269/s41997-020-00451-x  PMID: 33205377 
  21. Bi Q, Wu Y, Mei S, Ye C, Zou X, Zhang Z, et al. Epidemiology and transmission of COVID-19 in 391 cases and 1286 of their close contacts in Shenzhen, China: a retrospective cohort study. Lancet Infect Dis. 2020;20(8):911-9.  https://doi.org/10.1016/S1473-3099(20)30287-5  PMID: 32353347 
  22. Cheng H-Y, Jian S-W, Liu D-P, Ng T-C, Huang W-T, Lin H-H, et al. Contact tracing assessment of COVID-19 transmission dynamics in Taiwan and risk at different exposure periods before and after symptom onset. JAMA Intern Med. 2020;180(9):1156-63.  https://doi.org/10.1001/jamainternmed.2020.2020  PMID: 32356867 
  23. Hua CZ, Miao ZP, Zheng JS, Huang Q, Sun QF, Lu HP, et al. Epidemiological features and viral shedding in children with SARS-CoV-2 infection. J Med Virol. 2020;92(11):2804-12.  https://doi.org/10.1002/jmv.26180  PMID: 32542750 
  24. Jing Q-L, Liu M-J, Zhang Z-B, Fang L-Q, Yuan J, Zhang A-R, et al. Household secondary attack rate of COVID-19 and associated determinants in Guangzhou, China: a retrospective cohort study. Lancet Infect Dis. 2020;20(10):1141-50.  https://doi.org/10.1016/S1473-3099(20)30471-0  PMID: 32562601 
  25. Li W, Zhang B, Lu J, Liu S, Chang Z, Peng C, et al. Characteristics of household transmission of COVID-19. Clin Infect Dis. 2020;71(8):1943-6.  https://doi.org/10.1093/cid/ciaa450  PMID: 32301964 
  26. Li F, Li YY, Liu MJ, Fang LQ, Dean NE, Wong GWK, et al. Household transmission of SARS-CoV-2 and risk factors for susceptibility and infectivity in Wuhan: a retrospective observational study. Lancet Infect Dis. 2021;21(5):617-28.  https://doi.org/10.1016/S1473-3099(20)30981-6  PMID: 33476567 
  27. Wang Y, Tian H, Zhang L, Zhang M, Guo D, Wu W, et al. Reduction of secondary transmission of SARS-CoV-2 in households by face mask use, disinfection and social distancing: a cohort study in Beijing, China. BMJ Glob Health. 2020;5(5):e002794.  https://doi.org/10.1136/bmjgh-2020-002794  PMID: 32467353 
  28. Wu J, Huang Y, Tu C, Bi C, Chen Z, Luo L, et al. Household transmission of SARS-CoV-2, Zhuhai, China, 2020. Clin Infect Dis. 2020;71(16):2099-108.  https://doi.org/10.1093/cid/ciaa557  PMID: 32392331 
  29. Koureas M, Speletas M, Bogogiannidou Z, Babalis D, Pinakas V, Pinaka O, et al. Transmission dynamics of SARS-CoV-2 during an outbreak in a Roma community in Thessaly, Greece-control measures and lessons learned. Int J Environ Res Public Health. 2021;18(6):2878.  https://doi.org/10.3390/ijerph18062878  PMID: 33799791 
  30. Maltezou HC, Vorou R, Papadima K, Kossyvakis A, Spanakis N, Gioula G, et al. Transmission dynamics of SARS-CoV-2 within families with children in Greece: A study of 23 clusters. J Med Virol. 2021;93(3):1414-20.  https://doi.org/10.1002/jmv.26394  PMID: 32767703 
  31. Jagdale GR, Parande MA, Borle PS, Tapare VS, Tambe MP, Wavare S, et al. Secondary attack rate among the contacts of COVID-19 patients at the beginning of the pandemic in Pune City of Western Maharashtra, India. J Commun Dis. 2021;53(3):51-9.  https://doi.org/10.24321/0019.5138.202138 
  32. Somekh E, Gleyzer A, Heller E, Lopian M, Kashani-Ligumski L, Czeiger S, et al. The role of children in the dynamics of intra family coronavirus 2019 spread in densely populated area. Pediatr Infect Dis J. 2020;39(8):e202-4.  https://doi.org/10.1097/INF.0000000000002783  PMID: 32496407 
  33. Akaishi T, Kushimoto S, Katori Y, Kure S, Igarashi K, Takayama S, et al. COVID-19 transmission in group living environments and households. Sci Rep. 2021;11(1):11616.  https://doi.org/10.1038/s41598-021-91220-4  PMID: 34079047 
  34. Kuba Y, Shingaki A, Nidaira M, Kakita T, Maeshiro N, Oyama M, et al. Characteristics of household transmission of COVID-19 during its outbreak in Okinawa, Japan from February to May 2020. Jpn J Infect Dis. 2021;74(6):579-83.  https://doi.org/10.7883/yoken.JJID.2020.943  PMID: 33952770 
  35. Ng DC, Tan KK, Chin L, Cheng XL, Vijayakulasingam T, Liew DWX, et al. Risk factors associated with household transmission of SARS-CoV-2 in Negeri Sembilan, Malaysia. J Paediatr Child Health. 2022;58(5):769-73.  https://doi.org/10.1111/jpc.15821  PMID: 34723402 
  36. Reukers DFM, van Boven M, Meijer A, Rots N, Reusken C, Roof I, et al. High infection secondary attack rates of severe acute respiratory syndrome coronavirus 2 in Dutch households revealed by dense sampling. Clin Infect Dis. 2022;74(1):52-8.  https://doi.org/10.1093/cid/ciab237  PMID: 33822007 
  37. Telle K, Jørgensen SB, Hart R, Greve-Isdahl M, Kacelnik O. Secondary attack rates of COVID-19 in Norwegian families: a nation-wide register-based study. Eur J Epidemiol. 2021;36(7):741-8.  https://doi.org/10.1007/s10654-021-00760-6  PMID: 34036466 
  38. Yung CF, Kam KQ, Chong CY, Nadua KD, Li J, Tan NWH, et al. Household transmission of severe acute respiratory syndrome coronavirus 2 from adults to children. J Pediatr. 2020;225:249-51.  https://doi.org/10.1016/j.jpeds.2020.07.009  PMID: 32634405 
  39. Martínez-Baz I, Trobajo-Sanmartín C, Burgui C, Casado I, Castilla J. Transmission of SARS-CoV-2 infection and risk factors in a cohort of close contacts. Postgrad Med. 2022;134(2):230-8.  https://doi.org/10.1080/00325481.2022.2037360  PMID: 35102793 
  40. Lopez Bernal J, Panagiotopoulos N, Byers C, Garcia Vilaplana T, Boddington N, Zhang XS, et al. Transmission dynamics of COVID-19 in household and community settings in the United Kingdom, January to March 2020. Euro Surveill. 2022;27(15):2001551.  https://doi.org/10.2807/1560-7917.ES.2022.27.15.2001551  PMID: 35426357 
  41. Miller E, Waight PA, Andrews NJ, McOwat K, Brown KE, Höschler K, et al. Transmission of SARS-CoV-2 in the household setting: A prospective cohort study in children and adults in England. J Infect. 2021;83(4):483-9.  https://doi.org/10.1016/j.jinf.2021.07.037  PMID: 34348116 
  42. Laws RL, Chancey RJ, Rabold EM, Chu VT, Lewis NM, Fajans M, et al. Symptoms and Transmission of SARS-CoV-2 Among Children - Utah and Wisconsin, March-May 2020. Pediatrics. 2021;147(1):e2020027268.  https://doi.org/10.1542/peds.2020-027268  PMID: 33033178 
  43. Rosenberg ES, Dufort EM, Blog DS, Hall EW, Hoefer D, Backenson BP, et al. COVID-19 testing, epidemic features, hospital outcomes, and household prevalence, New York State—March 2020. Clin Infect Dis. 2020;71(8):1953-9.  https://doi.org/10.1093/cid/ciaa549  PMID: 32382743 
  44. Tanaka ML, Marentes Ruiz CJ, Malhotra S, Turner L, Peralta A, Lee Y, et al. SARS-CoV-2 transmission dynamics in households with children, Los Angeles, California. Front Pediatr. 2022;9:752993.  https://doi.org/10.3389/fped.2021.752993  PMID: 35071125 
  45. Yousaf AR, Duca LM, Chu V, Reses HE, Fajans M, Rabold EM, et al. A prospective cohort study in nonhospitalized household contacts with severe acute respiratory syndrome coronavirus 2 infection: symptom profiles and symptom change over time. Clin Infect Dis. 2021;73(7):e1841-9.  https://doi.org/10.1093/cid/ciaa1072  PMID: 32719874 
  46. Lyngse FP, Mølbak K, Skov RL, Christiansen LE, Mortensen LH, Albertsen M, et al. Increased transmissibility of SARS-CoV-2 lineage B.1.1.7 by age and viral load. Nat Commun. 2021;12(1):7251.  https://doi.org/10.1038/s41467-021-27202-x  PMID: 34903718 
  47. Lyngse FP, Mortensen LH, Denwood MJ, Christiansen LE, Møller CH, Skov RL, et al. Household transmission of the SARS-CoV-2 Omicron variant in Denmark. Nat Commun. 2022;13(1):5573.  https://doi.org/10.1038/s41467-022-33328-3  PMID: 36151099 
  48. Lyngse FP, Kirkeby CT, Denwood M, Christiansen LE, Mølbak K, Møller CH, et al. Household transmission of SARS-CoV-2 Omicron variant of concern subvariants BA.1 and BA.2 in Denmark. Nat Commun. 2022;13(1):5760.  https://doi.org/10.1038/s41467-022-33498-0  PMID: 36180438 
  49. Lyngse FP, Mølbak K, Denwood M, Christiansen LE, Møller CH, Rasmussen M, et al. Effect of vaccination on household transmission of SARS-CoV-2 Delta variant of concern. Nat Commun. 2022;13(1):3764.  https://doi.org/10.1038/s41467-022-31494-y  PMID: 35773247 
  50. Loenenbach A, Markus I, Lehfeld AS, An der Heiden M, Haas W, Kiegele M, et al. SARS-CoV-2 variant B.1.1.7 susceptibility and infectiousness of children and adults deduced from investigations of childcare centre outbreaks, Germany, 2021. Euro Surveill. 2021;26(21):2100433.  https://doi.org/10.2807/1560-7917.ES.2021.26.21.2100433  PMID: 34047274 
  51. Rajmohan P, Jose P, Thodi J, Thomas J, Raphael L, Krishna S, et al. Dynamics of transmission of COVID-19 cases and household contacts: A prospective cohort study. J Acute Dis. 2021;10(4):162-8.  https://doi.org/10.4103/2221-6189.321590 
  52. Layan M, Gilboa M, Gonen T, Goldenfeld M, Meltzer L, Andronico A, et al. Impact of BNT162b2 vaccination and Isolation on SARS-CoV-2 transmission in Israeli households: An observational study. Am J Epidemiol. 2022;191(7):1224-34.  https://doi.org/10.1093/aje/kwac042  PMID: 35238329 
  53. Ogata T, Tanaka H, Nozawa Y, Mukouyama K, Tanaka E, Osaki N, et al. Increased secondary attack rate among unvaccinated household contacts of coronavirus disease 2019 patients with delta variant in Japan. Int J Environ Res Public Health. 2022;19(7):3889.  https://doi.org/10.3390/ijerph19073889  PMID: 35409572 
  54. de Gier B, Andeweg S, Backer JA, Hahné SJ, van den Hof S, de Melker HE, et al. Vaccine effectiveness against SARS-CoV-2 transmission to household contacts during dominance of Delta variant (B.1.617.2), the Netherlands, August to September 2021. Euro Surveill. 2021;26(44):2100977.  https://doi.org/10.2807/1560-7917.ES.2021.26.44.2100977  PMID: 34738514 
  55. Verberk JDM, de Hoog MLA, Westerhof I, van Goethem S, Lammens C, Ieven G, et al. Transmission of SARS-CoV-2 within households: a remote prospective cohort study in European countries. Eur J Epidemiol. 2022;37(5):549-61.  https://doi.org/10.1007/s10654-022-00870-9  PMID: 35644003 
  56. Jalali N, Brustad HK, Frigessi A, MacDonald EA, Meijerink H, Feruglio SL, et al. Increased household transmission and immune escape of the SARS-CoV-2 Omicron compared to Delta variants. Nat Commun. 2022;13(1):5706.  https://doi.org/10.1038/s41467-022-33233-9  PMID: 36175424 
  57. Julin CH, Robertson AH, Hungnes O, Tunheim G, Bekkevold T, Laake I, et al. Household transmission of SARS-CoV-2: A prospective longitudinal study showing higher viral load and increased transmissibility of the Alpha variant compared to previous strains. Microorganisms. 2021;9(11):2371.  https://doi.org/10.3390/microorganisms9112371  PMID: 34835495 
  58. Cohen C, Kleynhans J, von Gottberg A, McMorrow ML, Wolter N, Bhiman JN, et al. SARS-CoV-2 incidence, transmission, and reinfection in a rural and an urban setting: results of the PHIRST-C cohort study, South Africa, 2020-21. Lancet Infect Dis. 2022;22(6):821-34.  https://doi.org/10.1016/S1473-3099(22)00069-X  PMID: 35298900 
  59. Watanapokasin N, Siripongboonsitti T, Ungtrakul T, Muadchimkaew M, Wongpatcharawarakul S, Auewarakul C, et al. Transmissibility of SARS-CoV-2 variants as a secondary attack in Thai households: a retrospective study. IJID Reg. 2021;1:1-2.  https://doi.org/10.1016/j.ijregi.2021.09.001  PMID: 35721778 
  60. Harris RJ, Hall JA, Zaidi A, Andrews NJ, Dunbar JK, Dabrera G. Effect of vaccination on household transmission of SARS-CoV-2 in England. N Engl J Med. 2021;385(8):759-60.  https://doi.org/10.1056/NEJMc2107717  PMID: 34161702 
  61. Singanayagam A, Hakki S, Dunning J, Madon KJ, Crone MA, Koycheva A, et al. Community transmission and viral load kinetics of the SARS-CoV-2 delta (B.1.617.2) variant in vaccinated and unvaccinated individuals in the UK: a prospective, longitudinal, cohort study. Lancet Infect Dis. 2022;22(2):183-95.  https://doi.org/10.1016/S1473-3099(21)00648-4  PMID: 34756186 
  62. Donnelly MAP, Chuey MR, Soto R, Schwartz NG, Chu VT, Konkle SL, et al. Household transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Alpha variant-United States, 2021. Clin Infect Dis. 2022;75(1):e122-32.  https://doi.org/10.1093/cid/ciac125  PMID: 35147176 
  63. Liu PY, Gragnani CM, Timmerman J, Newhouse CN, Soto G, Lopez L, et al. Pediatric household transmission of severe acute respiratory coronavirus-2 infection-Los Angeles County, December 2020 to February 2021. Pediatr Infect Dis J. 2021;40(10):e379-81.  https://doi.org/10.1097/INF.0000000000003251  PMID: 34387617 
  64. McLean HQ, Grijalva CG, Hanson KE, Zhu Y, Deyoe JE, Meece JK, et al. Household transmission and clinical features of SARS-CoV-2 infections. Pediatrics. 2022;149(3):e2021054178.  https://doi.org/10.1542/peds.2021-054178  PMID: 35194642 
  65. Sachdev DD, Chew Ng R, Sankaran M, Ernst A, Hernandez KT, Servellita V, et al. Contact tracing outcomes among household contacts of fully vaccinated coronavirus disease 2019 (COVID-19) patients: San Francisco, California, 29 January-2 July 2021. Clin Infect Dis. 2022;75(1):e267-75.  https://doi.org/10.1093/cid/ciab1042  PMID: 34928340 
  66. Chu VT, Yousaf AR, Chang K, Schwartz NG, McDaniel CJ, Lee SH, et al. Household transmission of SARS-CoV-2 from children and adolescents. N Engl J Med. 2021;385(10):954-6.  https://doi.org/10.1056/NEJMc2031915  PMID: 34289272 
  67. Galow L, Haag L, Kahre E, Blankenburg J, Dalpke AH, Lück C, et al. Lower household transmission rates of SARS-CoV-2 from children compared to adults. J Infect. 2021;83(1):e34-6.  https://doi.org/10.1016/j.jinf.2021.04.022  PMID: 33930468 
  68. Gorgels KMF, van Alphen LB, van der Veer BMJW, Hackert VH, Hensels AYJ, Heijer CDJD, et al. Increased transmissibility of SARS-CoV-2 alpha variant (B.1.1.7) in children: three large primary school outbreaks revealed by whole genome sequencing in the Netherlands. BMC Infect Dis. 2022;22(1):713.  https://doi.org/10.1186/s12879-022-07623-9  PMID: 36038845 
  69. Posfay-Barbe KM, Wagner N, Gauthey M, Moussaoui D, Loevy N, Diana A, et al. COVID-19 in children and the dynamics of infection in families. Pediatrics. 2020;146(2):e20201576.  https://doi.org/10.1542/peds.2020-1576  PMID: 32457213 
  70. Shah K, Kandre Y, Mavalankar D. Secondary attack rate in household contacts of COVID-19 Paediatric index cases: a study from Western India. J Public Health (Oxf). 2021;43(2):243-5.  https://doi.org/10.1093/pubmed/fdaa269  PMID: 33454742 
  71. Song JS, Lee J, Kim M, Jeong HS, Kim MS, Kim SG, et al. Serial intervals and household transmission of SARS-CoV-2 Omicron variant, South Korea, 2021. Emerg Infect Dis. 2022;28(3):756-9.  https://doi.org/10.3201/eid2803.212607  PMID: 35107418 
  72. Soriano-Arandes A, Gatell A, Serrano P, Biosca M, Campillo F, Capdevila R, et al. Household severe acute respiratory syndrome coronavirus 2 transmission and children: a network prospective study. Clin Infect Dis. 2021;73(6):e1261-9.  https://doi.org/10.1093/cid/ciab228  PMID: 33709135 
  73. Zhang M-X, Lin X-Q, Chen Y, Tung T-H, Zhu J-S. Determinants of parental hesitancy to vaccinate their children against COVID-19 in China. Expert Rev Vaccines. 2021;20(10):1339-49.  https://doi.org/10.1080/14760584.2021.1967147  PMID: 34376095 
  74. Deutsche Bundesregierung (BReg). The most important questions and answers about the coronavirus vaccination. Berlon: BReg; 2022. Available from: https://www.bundesregierung.de/breg-de/themen/coronavirus/coronavirus-vaccination-faq-1959802
  75. Tregoning JS, Schwarze J. Respiratory viral infections in infants: causes, clinical symptoms, virology, and immunology. Clin Microbiol Rev. 2010;23(1):74-98.  https://doi.org/10.1128/CMR.00032-09  PMID: 20065326 
  76. Zimmermann P, Curtis N. Why is COVID-19 less severe in children? A review of the proposed mechanisms underlying the age-related difference in severity of SARS-CoV-2 infections. Arch Dis Child. 2020;106(5):429-39.  https://doi.org/10.1136/archdischild-2020-320338  PMID: 33262177 
  77. Zhu Y, Chew KY, Wu M, Karawita AC, McCallum G, Steele LE, et al. Ancestral SARS-CoV-2, but not Omicron, replicates less efficiently in primary pediatric nasal epithelial cells. PLoS Biol. 2022;20(8):e3001728.  https://doi.org/10.1371/journal.pbio.3001728  PMID: 35913989 

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