Korean J Gastroenterol.  2021 Aug;78(2):117-128. 10.4166/kjg.2021.110.

SARS-CoV-2 Vaccination for Adult Patients with Inflammatory Bowel Disease: Expert Consensus Statements by KASID

• Lee YJ
• Kim SE
• Park YE
• Chang JY
• Song HJ
• Kim DH
• Yang YJ
• Kim BC
• Lee JG
• Yang HC
• Choi M
• Myung SJ
• The Clinical Practice Guideline Committee of the Korean Association for the Study of the Intestinal Diseases

• KMID: 2519380
• DOI: http://doi.org/10.4166/kjg.2021.110

Abstract

Coronavirus disease 2019 (COVID-19), caused by the novel coronavirus, is threatening global health worldwide with unprecedented contagiousness and severity. The best strategy to overcome COVID-19 is a vaccine. Various vaccines are currently being developed, and mass vaccination is in progress. Despite the very encouraging clinical trial results of these vaccines, there is insufficient information on the safety and efficacy of vaccines for inflammatory bowel disease (IBD) patients facing various issues. After reviewing current evidence and international guidelines, the Korean Association for the Study of Intestinal Diseases (KASID) developed an expert consensus statement on COVID-19 vaccination issues for Korean IBD patients. This expert consensus statement emphasizes that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination be strongly recommended for IBD patients, and it is safe for IBD patients receiving immunomodulatory therapy.

Keyword

COVID-19 vaccines; SARS-CoV-2; COVID-19; Inflammatory bowel diseases

Reference

1. WHO coronavirus (COVID-19) dashboard. [Internet]. World Health Organization;Geneva: Available from: https://covid19.who.int/. cited 2021 Jul 10. DOI: 10.46945/bpj.10.1.03.01.

2. Ng SC, Shi HY, Hamidi N, et al. 2017; Worldwide incidence and prevalence of inflammatory bowel disease in the 21st century: a systematic review of population-based studies. Lancet. 390:2769–2778. DOI: 10.1016/S0140-6736(17)32448-0. PMID: 29050646.

3. Yen HH, Weng MT, Tung CC, et al. 2019; Epidemiological trend in inflammatory bowel disease in Taiwan from 2001 to 2015: a nationwide populationbased study. Intest Res. 17:54–62. DOI: 10.5217/ir.2018.00096. PMID: 30449079. PMCID: PMC6361021.

4. Park SH, Kim YJ, Rhee KH, et al. 2019; A 30-year trend analysis in the epidemiology of inflammatory bowel disease in the Songpa-Kangdong District of Seoul, Korea in 1986-2015. J Crohns Colitis. 13:1410–1417. DOI: 10.1093/ecco-jcc/jjz081. PMID: 30989166.

5. Kirchgesner J, Lemaitre M, Carrat F, Zureik M, Carbonnel F, Dray-Spira R. 2018; Risk of serious and opportunistic infections associated with treatment of inflammatory bowel diseases. Gastroenterology. 155:337–346.e10. DOI: 10.1053/j.gastro.2018.04.012. PMID: 29655835.

6. Lichtenstein GR, Feagan BG, Cohen RD, et al. 2012; Serious infection and mortality in patients with Crohn's disease: more than 5 years of follow-up in the TREAT™ registry. Am J Gastroenterol. 10:1409–1422. DOI: 10.1038/ajg.2012.218. PMID: 22890223. PMCID: PMC3438468.

7. D'Amico F, Danese S, Peyrin-Biroulet L. 2020; Systematic review on inflammatory bowel disease patients with coronavirus disease 2019: it is time to take stock. Clin Gastroenterol Hepatol. 18:2689–2700. DOI: 10.1016/j.cgh.2020.08.003. PMID: 32777550. PMCID: PMC7831523.

8. D'Amico F, Rabaud C, Peyrin-Biroulet L, Danese S. 2021; SARS-CoV-2 vaccination in IBD: more pros than cons. Nat Rev Gastroenterol Hepatol. 18:211–213. DOI: 10.1038/s41575-021-00420-w. PMID: 33473178. PMCID: PMC7816748.

9. Q0A for SARS-CoV-2 vaccination. [Internet]. Korea Disease Control and Prevention Agency;Cheongju: Available from: https://ncv.kdca.go.kr/menu.es?mid=a12208000000. cited 2021 Jul 10.

10. Amit S, Regev-Yochay G, Afek A, Kreiss Y, Leshem E. 2021; Early rate reductions of SARS-CoV-2 infection and COVID-19 in BNT162b2 vaccine recipients. Lancet. 397:875–877. DOI: 10.1016/S0140-6736(21)00448-7. PMID: 33610193. PMCID: PMC7906709.

11. Frenck RW Jr, Klein NP, Kitchin N, et al. 2021; Safety, immunogenicity, and efficacy of the BNT162b2 COVID-19 vaccine in adolescents. N Engl J Med. 385:239–250. DOI: 10.1056/NEJMoa2107456. PMID: 34043894. PMCID: PMC8174030.

12. Haas EJ, Angulo FJ, McLaughlin JM, et al. 2021; Impact and effectiveness of mRNA BNT162b2 vaccine against SARS-CoV-2 infections and COVID-19 cases, hospitalisations, and deaths following a nationwide vaccination campaign in Israel: an observational study using national surveillance data. Lancet. 397:1819–1829. DOI: 10.1016/S0140-6736(21)00947-8. PMID: 33964222. PMCID: PMC8099315.

13. Hall VJ, Foulkes S, Saei A, et al. 2021; COVID-19 vaccine coverage in health-care workers in England and effectiveness of BNT162b2 mRNA vaccine against infection (SIREN): a prospective, multicentre, cohort study. Lancet. 397:1725–1735. DOI: 10.1016/S0140-6736(21)00790-X. PMID: 33901423. PMCID: PMC8064668.

14. Alexander JL, Moran GW, Gaya DR, et al. 2021; SARS-CoV-2 vaccination for patients with inflammatory bowel disease: a British Society of Gastroenterology Inflammatory Bowel Disease section and IBD Clinical Research Group position statement. Lancet Gastroenterol Hepatol. 6:218–224. DOI: 10.1016/S2468-1253(21)00024-8. PMID: 33508241. PMCID: PMC7834976.

15. Siegel CA, Melmed GY, McGovern DP, et al. 2021; SARS-CoV-2 vaccination for patients with inflammatory bowel diseases: recommendations from an international consensus meeting. Gut. 70:635–640. DOI: 10.1136/gutjnl-2020-324000. PMID: 33472895. PMCID: PMC7818789.

16. Rahier JF, Papay P, Salleron J, et al. 2011; H1N1 vaccines in a large observational cohort of patients with inflammatory bowel disease treated with immunomodulators and biological therapy. Gut. 60:456–462. DOI: 10.1136/gut.2010.233981. PMID: 21270121.

17. Mamula P, Markowitz JE, Piccoli DA, Klimov A, Cohen L, Baldassano RN. 2007; Immune response to influenza vaccine in pediatric patients with inflammatory bowel disease. Clin Gastroenterol Hepatol. 5:851–856. DOI: 10.1016/j.cgh.2007.02.035. PMID: 17544875.

18. Fiorino G, Peyrin-Biroulet L, Naccarato P, et al. 2012; Effects of immunosuppression on immune response to pneumococcal vaccine in inflammatory bowel disease: a prospective study. Inflamm Bowel Dis. 18:1042–1047. DOI: 10.1002/ibd.21800. PMID: 21674732.

19. See I, Su JR, Lale A, et al. 2021; US Case reports of cerebral venous sinus thrombosis with thrombocytopenia after Ad26.COV2.S vaccination, March 2 to April 21, 2021. JAMA. 325:2448–2456. DOI: 10.1001/jama.2021.7517. PMID: 33929487. PMCID: PMC8087975.

20. Greinacher A, Thiele T, Warkentin TE, Weisser K, Kyrle PA, Eichinger S. 2021; Thrombotic thrombocytopenia after ChAdOx1 nCov-19 vaccination. N Engl J Med. 384:2092–2101. DOI: 10.1056/NEJMoa2104840. PMID: 33835769. PMCID: PMC8095372.

21. AstraZeneca's COVID-19 vaccine: EMA finds possible link to very rare cases of unusual blood clots with low blood platelets. [Internet]. 2021. Jul. 4. Amsterdam: European Medicines Agency;Available from: https://www.ema.europa.eu/en/news/astrazenecas-covid-19-vaccine-ema-finds-possible-link-very-rare-cases-unusual-blood-clots-low-blood. cited 2021 Jul 10.

22. Guidance produced from the Expert Haematology Panel (EHP) focussed on Covid-19 vaccine induced thrombosis and thrombocytopenia (VITT). [Internet]. 2021. Apr. 7. Expert Haematology Panel;London: Available from: https://b-s-h.org.uk/media/19530/guidance-version-13-on-mngmt-of-thrombosis-with-thrombocytopenia-occurring-after-c-19-vaccine_20210407.pdf. cited 2021 Jul 10.

23. A prothrombotic thrombocytopenic disorder resembling heparin-induced thrombocytopenia following coronavirus-19 vaccination. [Internet]. 2021. Mar. 28. Research Square;Durham (NC): updated 2021 Apr 7; cited 2021 Jun 10. Available from: https://www.researchsquare.com/article/rs-362354/v1.

24. 2021. Feb. 5. Coronavirus vaccine - weekly summary of Yellow Card reporting. [Internet]. Medicines & Healthcare Products Regulatory Agency;London: Available from: https://www.gov.uk/government/publications/coronavirus-covid-19-vaccine-adverse-reactions/coronavirusvaccine-summary-of-yellow-card-reporting. updated 2021 Jul 1; cited 2021 Jul 6.

25. Johnson & Johnson's Janssen COVID-19 vaccine overview and safety. [Internet]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/different-vaccines/janssen.html. updated 2021 Jun 23 cited 2021 Jul 6.

26. Grainge MJ, West J, Card TR. 2010; Venous thromboembolism during active disease and remission in inflammatory bowel disease: a cohort study. Lancet. 375:657–663. DOI: 10.1016/S0140-6736(09)61963-2. PMID: 20149425.

27. Koroku M, Omori T, Kambayashi H, et al. Granulocyte and monocyte apheresis therapy for patients with active ulcerative colitis associated with COVID-19. Intest Res. 2021 Mar 12. [Epub ahead of print]. DOI: 10.5217/ir.2020.00148. PMID: 33902268.

28. Bezzio C, Saibeni S, Variola A, et al. 2020; Outcomes of COVID-19 in 79 patients with IBD in Italy: an IG-IBD study. Gut. 69:1213–1217. DOI: 10.1136/gutjnl-2020-321411. PMID: 32354990. PMCID: PMC7242872.

29. Brenner EJ, Ungaro RC, Gearry RB, et al. 2020; Corticosteroids, but not TNF antagonists, are associated with adverse COVID-19 outcomes in patients with inflammatory bowel diseases: results from an international registry. Gastroenterology. 159:481–491.e3. DOI: 10.1053/j.gastro.2020.05.032. PMID: 32425234. PMCID: PMC7233252.

30. Ungaro RC, Brenner EJ, Gearry RB, et al. 2021; Effect of IBD medications on COVID-19 outcomes: results from an international registry. Gut. 70:725–732. DOI: 10.1136/gutjnl-2020-322539. PMID: 33082265. PMCID: PMC8136807.

31. Kennedy NA, Jones GR, Lamb CA, et al. 2020; British Society of Gastroenterology guidance for management of inflammatory bowel disease during the COVID-19 pandemic. Gut. 69:984–990. DOI: 10.1136/gutjnl-2020-321244. PMID: 32303607. PMCID: PMC7211081.

32. Polack FP, Thomas SJ, Kitchin N, et al. 2020; Safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine. N Engl J Med. 383:2603–2615. DOI: 10.1056/NEJMoa2034577. PMID: 33301246. PMCID: PMC7745181.

33. Voysey M, Clemens SAC, Madhi SA, et al. 2021; Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK. Lancet. 397:99–111. DOI: 10.1016/S0140-6736(20)32661-1. PMID: 33306989. PMCID: PMC7723445.

34. Baden LR, El Sahly HM, Essink B, et al. 2021; Efficacy and safety of the mRNA-1273 SARS-CoV-2 vaccine. N Engl J Med. 384:403–416. DOI: 10.1056/NEJMoa2035389. PMID: 33378609. PMCID: PMC7787219.

35. Wong SY, Dixon R, Martinez Pazos V, et al. 2021; Serologic response to messenger RNA coronavirus disease 2019 vaccines in inflammatory bowel disease patients receiving biologic therapies. Gastroenterology. 161:715–718.e4. DOI: 10.1053/j.gastro.2021.04.025. PMID: 33887219. PMCID: PMC8055494.

36. Kennedy NA, Lin S, Goodhand JR, et al. Infliximab is associated with attenuated immunogenicity to BNT162b2 and ChAdOx1 nCoV-19 SARS-CoV-2 vaccines in patients with IBD. Gut. 2021 Apr 26. [Epub ahead of print]. DOI: 10.1136/gutjnl-2021-324789. PMID: 33903149. PMCID: PMC8076631.

37. Melmed GY, Rubin DT, McGovern DPB. 2021; Winter is coming! Clinical, immunologic, and practical considerations for vaccinating patients with inflammatory bowel disease during the coronavirus disease-2019 pandemic. Gastroenterology. 160:639–644. DOI: 10.1053/j.gastro.2020.10.013. PMID: 33065064. PMCID: PMC7553998.

38. Rubin LG, Levin MJ, Ljungman P, et al. 2014; 2013 IDSA clinical practice guideline for vaccination of the immunocompromised host. Clin Infect Dis. 58:309–318. DOI: 10.1093/cid/cit816. PMID: 24421306.

39. Park SK, Choi CH, Chun J, et al. 2020; Prevention and management of viral hepatitis in inflammatory bowel disease: a clinical practice guideline by the Korean Association for the Study of Intestinal Diseases. Intest Res. 18:18–33. DOI: 10.5217/ir.2019.09155. PMID: 32013312. PMCID: PMC7000641.

40. Crosby S, Schuh MJ, Caldera F, Farraye FA. 2021; Vaccination of patients with inflammatory bowel disease during the COVID-19 pandemic. Gastroenterol Hepatol (N Y). 17:18–30. PMID: 34035759. PMCID: PMC8132679.

41. Queiroz NSF, Teixeira FV, Freire CCF, et al. 2021; Brazilian IBD study group position statement on SARS-COV2 vaccination. Arq Gastroenterol. 58:1–4. DOI: 10.1590/s0004-2803.202100000-02. PMID: 33909805.

42. deBruyn J, Fonseca K, Ghosh S, et al. 2016; Immunogenicity of influenza vaccine for patients with inflammatory bowel disease on maintenance infliximab therapy: a randomized trial. Inflamm Bowel Dis. 22:638–647. DOI: 10.1097/MIB.0000000000000615. PMID: 26595551.

43. Melmed GY, Agarwal N, Frenck RW, et al. 2010; Immunosuppression impairs response to pneumococcal polysaccharide vaccination in patients with inflammatory bowel disease. Am J Gastroenterol. 105:148–154. DOI: 10.1038/ajg.2009.523. PMID: 19755964.

44. Pratt PK Jr, David N, Weber HC, et al. 2018; Antibody response to hepatitis B virus vaccine is impaired in patients with inflammatory bowel disease on infliximab therapy. Inflamm Bowel Dis. 24:380–386. DOI: 10.1093/ibd/izx001. PMID: 29361083.

45. Andrade P, Santos-Antunes J, Rodrigues S, Lopes S, Macedo G. 2015; Treatment with infliximab or azathioprine negatively impact the efficacy of hepatitis B vaccine in inflammatory bowel disease patients. J Gastroenterol Hepatol. 30:1591–1595. DOI: 10.1111/jgh.13001. PMID: 25967740.

46. Park SH, Yang SK, Park SK, et al. 2014; Efficacy of hepatitis A vaccination and factors impacting on seroconversion in patients with inflammatory bowel disease. Inflamm Bowel Dis. 20:69–74. DOI: 10.1097/01.MIB.0000437736.91712.a1. PMID: 24284413.

47. Agarwal N, Ollington K, Kaneshiro M, Frenck R, Melmed GY. 2012; Are immunosuppressive medications associated with decreased responses to routine immunizations? A systematic review. Vaccine. 30:1413–1424. DOI: 10.1016/j.vaccine.2011.11.109. PMID: 22197580.

48. Wyant T, Leach T, Sankoh S, et al. 2015; Vedolizumab affects antibody responses to immunisation selectively in the gastrointestinal tract: randomised controlled trial results. Gut. 64:77–83. DOI: 10.1136/gutjnl-2014-307127. PMID: 24763133.

49. Andrisani G, Frasca D, Romero M, et al. 2013; Immune response to influenza A/H1N1 vaccine in inflammatory bowel disease patients treated with anti TNF-α agents: effects of combined therapy with immunosuppressants. J Crohns Colitis. 7:301–307. DOI: 10.1016/j.crohns.2012.05.011. PMID: 22673636. PMCID: PMC3862353.

50. Sempere L, Almenta I, Barrenengoa J, et al. 2013; Factors predicting response to hepatitis B vaccination in patients with inflammatory bowel disease. Vaccine. 31:3065–3071. DOI: 10.1016/j.vaccine.2013.04.059. PMID: 23664999.

51. Kim SB, Park SJ, Chung SH, et al. 2014; Vaccination and complementary and alternative medicine in patients with inflammatory bowel disease. Intest Res. 12:124–130. DOI: 10.5217/ir.2014.12.2.124. PMID: 25349579. PMCID: PMC4204702.

52. Tinsley A, Navabi S, Williams ED, et al. 2019; Increased risk of influenza and influenza-related complications among 140,480 patients with inflammatory bowel disease. Inflamm Bowel Dis. 25:369–376. DOI: 10.1093/ibd/izy243. PMID: 30020478.

53. Kantsø B, Simonsen J, Hoffmann S, Valentiner-Branth P, Petersen AM, Jess T. 2015; Inflammatory bowel disease patients are at increased risk of invasive pneumococcal disease: a nationwide Danish cohort study 1977-2013. Am J Gastroenterol. 110:1582–1587. DOI: 10.1038/ajg.2015.284. PMID: 26346865.

54. Farraye FA, Melmed GY, Lichtenstein GR, Kane SV. 2017; ACG clinical guideline: preventive care in inflammatory bowel disease. Am J Gastroenterol. 112:241–258. DOI: 10.1038/ajg.2016.537. PMID: 28071656.

55. Grohskopf LA, Alyanak E, Broder KR, et al. 2020; Prevention and control of seasonal influenza with vaccines: recommendations of the advisory committee on immunization practices - United States, 2020-21 influenza season. MMWR Recomm Rep. 69:1–24. DOI: 10.15585/mmwr.rr6908a1. PMID: 32820746. PMCID: PMC7439976.

56. Magro F, Rahier JF, Abreu C, et al. 2020; Inflammatory bowel disease management during the COVID-19 outbreak: The Ten Dós and Don'ts from the ECCO-COVID taskforce. J Crohns Colitis. 14(14 Suppl 3):S798–S806. DOI: 10.1093/ecco-jcc/jjaa160. PMID: 32722754. PMCID: PMC7454472.

57. Kim KO, Jang BI. Management of inflammatory bowel disease in the COVID-19 era. Intest Res. 2021 Feb 3. [Epub ahead of print]. DOI: 10.5217/ir.2020.00156. PMID: 33525860.

58. Guidelines for COVID-19 vaccination project, 3rd edition. [Internet]. 2021. Jul. 16. Korea Disease Control and Prevention Agency;Cheongju: Available from: https://ncv.kdca.go.kr/boardDownload.es?bid=0031&list_no=472&seq=1. updated 2021 Jul 16, cited 2021 Jul 16.

59. Zambrano LD, Ellington S, Strid P, et al. 2020; Update: characteristics of symptomatic women of reproductive age with laboratory-confirmed SARS-CoV-2 infection by pregnancy status - United States, January 22-October 3, 2020. MMWR Morb Mortal Wkly Rep. 69:1641–1647. DOI: 10.15585/mmwr.mm6944e3. PMID: 33151921. PMCID: PMC7643892.

60. Allotey J, Stallings E, Bonet M, et al. 2020; Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and metaanalysis. BMJ. 370:m3320. DOI: 10.1136/bmj.m3320. PMID: 32873575. PMCID: PMC7459193.

61. Kotlyar AM, Grechukhina O, Chen A, et al. 2021; Vertical transmission of coronavirus disease 2019: a systematic review and meta-analysis. Am J Obstet Gynecol. 224:35–53.e3. DOI: 10.1016/j.ajog.2020.07.049. PMID: 32739398. PMCID: PMC7392880.

62. Rasmussen SA, Jamieson DJ. 2021; Pregnancy, postpartum care, and COVID-19 vaccination in 2021. JAMA. 325:1099–1100. DOI: 10.1001/jama.2021.1683. PMID: 33555287.

63. Steinhoff MC, Katz J, Englund JA, et al. 2017; Year-round influenza immunisation during pregnancy in Nepal: a phase 4, randomised, placebo-controlled trial. Lancet Infect Dis. 17:981–989. DOI: 10.1016/S1473-3099(17)30252-9. PMID: 28522338. PMCID: PMC5573632.

64. Winter K, Nickell S, Powell M, Harriman K. 2017; Effectiveness of prenatal versus postpartum tetanus, diphtheria, and acellular pertussis vaccination in preventing infant pertussis. Clin Infect Dis. 64:3–8. DOI: 10.1093/cid/ciw634. PMID: 27624955.

65. Adhikari EH, Spong CY. 2021; COVID-19 vaccination in pregnant and lactating women. JAMA. 325:1039–1040. DOI: 10.1001/jama.2021.1658. PMID: 33555297.

66. 2021. Feb. 16. SOGC COVID-19 vaccination in pregnancy FAQ for health care providers. [Internet]. The Society of Obstetricians and Gynaecologists of Canada;Ottawa: updated 2021 May 21; cited 2021 Jul 10. Available from: https://sogc.org/common/Uploaded%20files/Covid%20Information/EN_HCP-FAQ_SOGC_FINAL.pdf.

67. 2021. COVID-19 vaccines for people who are pregnant or breastfeeding. [Internet]. Centers for Disease Control and Prevention;Atlanta (GA): Available from: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/recommendations/pregnancy.html. updated 2021 Jun 29 cited 2021 Jul 7.

68. Vaccines and Related Biological Products Advisory Committee meeting-December 17, 2020-FDA briefing document- Moderna COVID-19 vaccine. [Internet]. 2021. Jan. 27. U. S. Food and Drug Administration;Silver Spring (MD): Available from: https://www.fda.gov/media/144434/download. cited 2021 Jun 26.

69. 2021. Jul. 7. V-safe COVID-19 vaccine pregnancy registry. [Internet]. Available from: https://www.cdc.gov/coronavirus/2019-ncov/vaccines/safety/vsafepregnancyregistry.html. updated 2021 Jul 26; cited 2021 Jul 7.

70. Shimabukuro TT, Kim SY, Myers TR, et al. 2021; Preliminary findings of mRNA COVID-19 vaccine safety in pregnant persons. N Engl J Med. 384:2273–2282. DOI: 10.1056/NEJMoa2104983. PMID: 33882218. PMCID: PMC8117969.

71. Gray KJ, Bordt EA, Atyeo C, et al. Coronavirus disease 2019 vaccine response in pregnant and lactating women: a cohort study. Am J Obstet Gynecol. 2021 Mar 26. [Epub ahead of print]. DOI: 10.1016/j.ajog.2021.03.023. PMCID: PMC7997025. PMID: 33775692.

72. 2021. Jun. 2. Update on WHO Interim recommendations on COVID-19 vaccination of pregnant and lactating women. [Internet]. World Health Organization;Geneva: Available from: https://cdn.who.int/media/docs/default-source/2021-dha-docs/update-on-who-interim-recommendations-on-c-19-vaccination-for-pregnant-and-lactating-women-70-.pdf?sfvrsn=2c1d9ac8_1&download=true. updated 2021 Jun 10; cited 2021 Jun 26.

73. 2020. Dec. 30. Joint Committee on Vaccination and Immunisation: advice on priority groups for COVID-19 vaccination. [Internet]. GOV.UK;London: Available from: https://www.gov.uk/government/publications/priority-groups-for-coronavirus-covid-19-vaccination-advice-from-the-jcvi-30-december-2020/joint-committee-on-vaccination-and-immunisation-advice-on-priority-groups-for-covid-19-vaccination-30-december-2020. updated 2021 Jan 6; cited 2021 Jun 24.

74. JCVI issues new advice on COVID-19 vaccination for pregnant women. [Internet]. 2021. Apr. 16. GOV.UK;London: Available from: https://www.gov.uk/government/news/jcviissues-new-advice-on-covid-19-vaccination-for-pregnant-women. cited 2021 Jul 5.

75. Martins I, Louwen F, Ayres-de-Campos D, Mahmood T. 2021; EBCOG position statement on COVID-19 vaccination for pregnant and breastfeeding women. Eur J Obstet Gynecol Reprod Biol. 262:256–258. DOI: 10.1016/j.ejogrb.2021.05.021. PMID: 34020833. PMCID: PMC8120807.

76. 2021. Mar. 18. UK regulator confirms that people should continue to receive the COVID-19 vaccine AstraZeneca. [Internet]. Medicines and Healthcare products Regulatory Agency;London: Available from: https://www.gov.uk/government/news/uk-regulator-confirmsthat-people-should-continue-to-receive-the-covid-19-vaccine-astrazeneca. updated 2021 Apr 7; cited 2021 Jun 26.

77. Choi WS. 2021; Comprehensive understanding and field application of COVID-19 vaccine. Korean J Med. 96:155–159. DOI: 10.3904/kjm.2021.96.3.155.

78. Coronavirus (COVID-19), pregnancy, and breastfeeding: a message for patients. [Internet]. American College of Obstetricians and Gynecologists;Washington (DC): Available from: https://www.acog.org/womens-health/faqs/coronavirus-covid-19-pregnancy-and-breastfeeding. updated 2021 Aug 4; cited 2021 Jul 5.

79. Perl SH, Uzan-Yulzari A, Klainer H, et al. 2021; SARS-CoV-2-specific antibodies in breast milk after COVID-19 vaccination of breastfeeding women. JAMA. 325:2013–2014. DOI: 10.1001/jama.2021.5782. PMID: 33843975. PMCID: PMC8042567.

80. 2021. COVID-19 vaccines, pregnancy and breastfeeding. [Internet]. Royal College of Obstetricians and Gynaecologists;London: Available from: https://www.rcog.org.uk/en/guidelines-research-services/coronavirus-covid-19-pregnancy-and-womens-health/covid-19-vaccines-and-pregnancy/covid-19-vaccines-pregnancy-and-breastfeeding/. updated 2021 Jul 19; cited 2021 Jul 5.

81. What vaccines are available in Korea? [Internet]. Korea Disease Control and Prevention Agency;Cheongju: Available from: https://ncv.kdca.go.kr/menu.es?mid=a10119000000. cited 2021 Jul 30.