Updated guidance on COVID-19 vaccines for individuals who are pregnant or breastfeeding

Publication date: September 9, 2022

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Organization: Public Health Agency of Canada

Cat.: HP40-322/1-2022E-PDF

ISBN: 978-0-660-45350-7

Pub.: 220408

Published: 2022-09-09

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Preamble

The National Advisory Committee on Immunization (NACI) is an External Advisory Body that provides the Public Health Agency of Canada (PHAC) with independent, ongoing and timely medical, scientific, and public health advice in response to questions from PHAC relating to immunization.

In addition to burden of disease and vaccine characteristics, PHAC has expanded the mandate of NACI to include the systematic consideration of programmatic factors in developing evidence based recommendations to facilitate timely decision-making for publicly funded vaccine programs at provincial and territorial levels.

The additional factors to be systematically considered by NACI include: economics, ethics, equity, feasibility, and acceptability. Not all NACI statements will require in-depth analyses of all programmatic factors. While systematic consideration of programmatic factors will be conducted using evidence-informed tools to identify distinct issues that could impact decision-making for recommendation development, only distinct issues identified as being specific to the vaccine or vaccine-preventable disease will be included.

This statement contains NACI's independent advice and recommendations, which are based upon the best current available scientific knowledge. This document is being disseminated for information purposes. People administering the vaccine should also be aware of the contents of the relevant product monograph. Recommendations for use and other information set out herein may differ from that set out in the product monographs of the Canadian manufacturers of the vaccines. Manufacturer(s) have sought approval of the vaccines and provided evidence as to its safety and efficacy only when it is used in accordance with the product monographs. NACI members and liaison members conduct themselves within the context of PHAC's Policy on Conflict of Interest, including yearly declaration of potential conflict of interest.

Background

On June 29, 2022, NACI published interim guidance on planning considerations for a fall 2022 COVID-19 vaccine booster program in Canada. NACI identified people who are pregnant among those who are at increased risk of severe illness from COVID-19 and strongly recommended that pregnant people should be offered a fall COVID-19 booster dose regardless of the number of booster doses previously received.

The NACI recommendations for the use of COVID-19 vaccines in pregnancy and breastfeeding have evolved over time with accumulating evidence since the authorization of the first COVID-19 vaccines. Initially, in December 2020, NACI took a precautionary approach by recommending against routinely offering COVID-19 vaccines to populations excluded from clinical trials, including people who were pregnant or breastfeeding. On May 28, 2021, the committee updated their guidance to strongly recommend the use of mRNA COVID-19 vaccines in pregnant or breastfeeding populations, given the accumulated data on the safety of COVID-19 vaccines in these groups and the emerging evidence at that time on risks of SARS-CoV-2 infection in the context of pregnancy. Pregnant adults and adolescents have been recommended to receive a booster dose of mRNA COVID-19 vaccine since December 3, 2021 and January 28, 2022, respectively.

Since that time:

In this statement, NACI reaffirms the importance and safety of COVID-19 vaccination during pregnancy and breastfeeding to address the disproportionate risk of severe COVID-19 disease in people who are pregnant, with the goal of reducing the incidence of adverse outcomes for pregnant persons, fetuses and newborns from COVID-19 disease.

NACI continues to strongly recommend that individuals who are pregnant or breastfeeding should be immunized with a primary series of an authorized mRNA vaccine. NACI also reiterates its existing recommendations for booster doses in these populations. For further information on these recommendations, please refer to the COVID-19 vaccine chapter in the Canadian Immunization Guide (CIG).

NACI continues to monitor the rapidly evolving scientific data, recognizing that the trajectory of the COVID-19 pandemic remains unclear. Updated recommendations will be made as needed.

Methods

NACI's recommendations on booster doses are based on the decision-making framework outlined in the published statement Interim guidance on booster COVID-19 vaccine doses in Canada. This framework has been updated with evolving evidence (e.g., including consideration of population level cumulative immunity and vaccine coverage) as outlined in Table 1 (of the above-mentioned framework). Recommendations are based on evidence of the need for (e.g., increased risk of severe illness from COVID-19 and/or increased risk of decreased protection, and waning protection due to increased time since last dose or infection) and benefit of (e.g., safety and effectiveness) booster doses in the Canadian context.

On June 2, 14 and 28 of 2022, the NACI COVID-19 Working Group, which included external clinical and academic experts in pregnancy and breastfeeding, reviewed data on the current epidemiology of COVID-19 in pregnancy, vaccine safety, vaccine effectiveness and immunogenicity, gestational timing of vaccination, and vaccination during breastfeeding.

NACI approved the following recommendations on July 5, 2022. Evidence released or published after this date was not included in this statement.

For further information on NACI's recommendations on the use of COVID-19 vaccines, please refer to NACI's Statements and publications and the COVID-19 vaccine chapter in the Canadian Immunization Guide (CIG).

Further information on NACI's process and procedures is available elsewhere Footnote 7 Footnote 8.

Recommendations

Consistent with NACI's Interim guidance on planning considerations for a fall 2022 COVID-19 vaccine booster program in Canada:

NACI strongly recommends that individuals who are pregnant should be offered a fall COVID-19 vaccine booster dose regardless of the number of booster doses previously received.

With regard to timing of vaccination during pregnancy:

  1. NACI recommends that the fall COVID-19 booster dose should be offered at any stage of pregnancy (i.e., in any trimester), regardless of the number of booster doses previously received. (Strong NACI recommendation)
  1. NACI recommends that COVID-19 vaccine booster doses may be offered at an interval of 6 months since previous COVID-19 vaccine dose or SARS-CoV-2 infection. However, a shorter interval of at least 3 months may be warranted to optimize protection for the pregnant person in the context of heightened epidemiological risk (including increased risk of severe outcomes in pregnant people). (Discretionary NACI recommendation)
  • An individual may receive all doses for which they are eligible during the course of a pregnancy.

Consistent with existing recommendations in NACI's Interim guidance on planning considerations for a fall 2022 COVID-19 vaccine booster program in Canada:

  • Individuals who are breastfeeding may be offered a fall COVID-19 vaccine booster dose, regardless of the number of booster doses previously received.
  • Individuals at increased risk of severe illness from COVID-19* who are breastfeeding should be offered a fall COVID-19 vaccine booster dose regardless of the number of booster doses previously received.

*For details regarding who is considered at increased risk of severe illness, refer to NACI's Interim guidance on planning considerations for a fall 2022 COVID-19 vaccine booster program in Canada.

With regard to the use of authorized bivalent Omicron-containing mRNA COVID-19 vaccine products for people who are pregnant or breastfeeding:

  • Reformulations of previously-recommended mRNA vaccines can be recommended for use in pregnant or breastfeeding individuals without contraindications to the vaccine, based on reassuring published data regarding the safety of mRNA vaccines in pregnancy.
  • Individuals eligible for a fall booster dose, particularly those in groups at a higher risk of severe outcomes from COVID-19, should not delay their planned vaccination in anticipation of a bivalent Omicron-containing mRNA vaccine if it is not yet available. Individuals choosing to delay a booster dose in anticipation of a new vaccine formulation should carefully assess their individual risks (i.e., risks of SARS-CoV-2 infection and severe outcomes from COVID-19) and benefits associated with deferring a booster dose.
  • If the bivalent Omicron-containing mRNA COVID-19 vaccine is not readily available, an original mRNA COVID-19 vaccine should be offered to ensure timely protection.
  • There are currently no data on the use of bivalent Omicron-containing mRNA COVID-19 vaccines as part of a primary series and therefore NACI continues to recommend that a primary series be completed using original mRNA COVID-19 vaccines. NACI will continue to monitor the evidence as it emerges and update recommendations as needed.

NACI also reiterates its existing recommendations:

  • Individuals who are pregnant or breastfeeding who have not yet begun or completed their primary vaccine series should be offered the recommended doses. Administration of the COVID-19 primary vaccine series remains a top priority in Canada as unvaccinated or partially vaccinated individuals continue to be disproportionately affected by severe COVID-19 disease.
  • If individuals who are pregnant or breastfeeding have not yet received a first booster dose, NACI continues to strongly recommend that a first booster dose be offered.
  • COVID-19 vaccines may be administered concurrently with (i.e., same day), or at any time before or after other vaccines recommended during pregnancy or while breastfeeding.

Summary of evidence

Severity of COVID-19 in pregnant people and their infants

Safety of COVID-19 vaccine in pregnancy

Safety of COVID-19 vaccine during breastfeeding

Effectiveness of COVID-19 vaccination during pregnancy

Considerations for gestational timing of a booster dose

Vaccination and breastmilk antibodies

Research priorities

  1. Continuous monitoring of the burden of disease among people who are pregnant and infants in future COVID-19 waves as SARS-CoV-2 evolves.
  2. Continuous monitoring of data on the safety, immunogenicity, efficacy, and effectiveness of the COVID-19 vaccines in pregnancy and breastfeeding, including booster doses and new COVID-19 vaccine products, through clinical trials and studies in real-world settings. This should include the degree and duration of protection conferred by each booster dose against circulating variants. The research should also consider the clinical implications of previous SARS-CoV-2 infection; repeated immunization; and outcomes (including longer-term outcomes) after vaccination or infection in pregnant or breastfeeding individuals and neonates.
  3. Further characterization of vaccine confidence and acceptability among people who are pregnant, including in racialized and other groups that experience higher burden of disease in pregnancy and lower vaccine uptake, in order to develop strategies to reduce health inequities in these populations.
  4. Further evaluation of the optimal gestational timing of boosters in people who are pregnant, with respect to the safety profile, duration or waning of protection against infection and severe disease for both pregnant people and their infants, and the potential for immune interference in infants ≥6 months with transplacentally-acquired antibodies who are subsequently vaccinated with a COVID-19 vaccine.

Table 1. Strength of NACI recommendations

Strength of NACI recommendation
based on factors not isolated to strength of evidence
(e.g., public health need)

Strong

Discretionary

Wording

"should/should not beoffered"

"may/may not beoffered"

Rationale

Known/anticipated advantages outweigh known/anticipated disadvantages ("should"),
or
Known/Anticipated disadvantages outweigh known/anticipated advantages ("should not")

Known/anticipated advantages are closely balanced with known/anticipated disadvantages,
or
Uncertainty in the evidence of advantages and disadvantages exists

Implication

A strong recommendation applies to most populations/individuals and should be followed unless a clear and compelling rationale for an alternative approach is present.

A discretionary recommendation may be considered for some populations/individuals in some circumstances. Alternative approaches may be reasonable.

Acknowledgments

This statement was prepared by: A Nunn, NK Abraham, C Jensen, N Mohamed, R Krishnan, S Wilson, J Zafack, M Salvadori, R Harrison, and S Deeks on behalf of NACI.

NACI gratefully acknowledges the contribution of: K Ramotar, A Stevens, M Hersi, SH Lim, S Pierre, and CY Jeong.

NACI members: S Deeks (Chair), R Harrison (Vice-Chair), M Andrew, J Bettinger, N Brousseau, H Decaluwe, P De Wals, E Dubé, V Dubey, K Hildebrand, K Klein, M O'Driscoll, J Papenburg, A Pham-Huy, B Sander, and S Wilson.

Liaison representatives: L Bill (Canadian Indigenous Nurses Association), LM Bucci (Canadian Public Health Association), E Castillo (Society of Obstetricians and Gynaecologists of Canada), A Cohn (Centers for Disease Control and Prevention, United States), J Comeau (Association of Medical Microbiology and Infectious Disease Canada), L Dupuis (Canadian Nurses Association), D Fell (Canadian Association for Immunization Research and Evaluation), E Adams (Indigenous Physicians Association of Canada), J Hu (College of Family Physicians of Canada), M Lavoie (Council of Chief Medical Officers of Health), D Moore (Canadian Paediatric Society), M Naus (Canadian Immunization Committee), and A Ung (Canadian Pharmacists Association).

Ex-officio representatives: V Beswick-Escanlar (National Defence and the Canadian Armed Forces), E Henry (Centre for Immunization and Respiratory Infectious Diseases (CIRID), PHAC), M Lacroix (Public Health Ethics Consultative Group, PHAC), C Lourenco (Biologic and Radiopharmaceutical Drugs Directorate, Health Canada), D MacDonald (COVID-19 Epidemiology and Surveillance, PHAC), S Ogunnaike-Cooke (CIRID, PHAC), K Robinson (Marketed Health Products Directorate, HC), M Routledge (National Microbiology Laboratory, PHAC), and T Wong (First Nations and Inuit Health Branch, Indigenous Services Canada).

NACI COVID-19 Vaccine Working Group:

Members: S Wilson (Chair), M Adurogbangba, M Andrew, Y Bui, H Decaluwe, P De Wals, V Dubey, S Hosseini-Moghaddam, M Miller, D Moore, S Oliver, and E Twentyman.

External experts (topic of pregnancy and breastfeeding): T Bogler, I Boucoiran, K Campbell, E Castillo, D Fell, D Money, and V Poliquin.

PHAC participants: NK Abraham, N Alluqmani, O Baclic, L Coward, N Forbes, C Jensen, CY Jeong, A Killikelly, R Krishnan, SH Lim, N Mohamed, J Montroy, A Nam, A Nunn, S Pierre, R Pless, M Salvadori, A Sinilaite, A Stevens, E Tice, A Tuite, MC Tunis, E Wong, R Ximenes, MW Yeung, and J Zafack.

References

Footnote 1

Murison KR, Grima AA, Simmons AE, Tuite AR, Fisman DN. Severity of SARS-CoV-2 Infection in Pregnancy in Ontario: A Matched Cohort Analysis. Clin Infect Dis. 2022 Jul 6:ciac544. doi: 10.1093/cid/ciac544.

Return to footnote 1 referrer

Footnote 2

McClymont E, Albert AY, Alton GD, Boucoiran I, Castillo E, Fell DB, et al. Association of SARS-CoV-2 Infection During Pregnancy With Maternal and Perinatal Outcomes. JAMA. 2022 May 24;327(20):1983,1991. doi: 10.1001/jama.2022.5906.

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Footnote 3

Marchand G, Patil AS, Masoud AT, Ware K, King A, Ruther S, et al. Systematic review and meta-analysis of COVID-19 maternal and neonatal clinical features and pregnancy outcomes up to June 3, 2021. AJOG Glob Rep. 2022 Feb;2(1):100049. doi: 10.1016/j.xagr.2021.100049.

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Footnote 4

Sturrock S, Ali S, Gale C, Battersby C, Doare KL. Neonatal outcomes and indirect consequences following maternal SARS-CoV-2 infection in pregnancy: A systematic review. medRxiv. 2022 May 21. https://doi.org/10.1101/2022.05.20.22275313.

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Footnote 5

Norman M, Navér L, Söderling J, Ahlberg M, Hervius Askling H, Aronsson B, et al. Association of Maternal SARS-CoV-2 Infection in Pregnancy With Neonatal Outcomes. JAMA. 2021 May 25;325(20):2076,2086. doi: 10.1001/jama.2021.5775.

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Footnote 6

D. Personal communication. Temporal trends and determinants of COVID-19 vaccine coverage and series initiation during pregnancy in Ontario, Canada, December 2020 to December 2021. 2022 May 6.

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Footnote 7

Ismail SJ, Langley JM, Harris TM, Warshawsky BF, Desai S, FarhangMehr M. Canada's National Advisory Committee on Immunization (NACI): Evidence-based decision-making on vaccines and immunization. Vaccine. 2010;28:A58,63. doi: 10.1016/j.vaccine.2010.02.035

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Footnote 8

Ismail SJ, Hardy K, Tunis MC, Young K, Sicard N, Quach C. A framework for the systematic consideration of ethics, equity, feasibility, and acceptability in vaccine program recommendations. Vaccine. 2020 Aug 10;38(36):5861,5876. doi: 10.1016/j.vaccine.2020.05.051.

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Footnote 9

Allotey J, Stallings E, Bonet M, Yap M, Chatterjee S, Kew T, et al. Clinical manifestations, risk factors, and maternal and perinatal outcomes of coronavirus disease 2019 in pregnancy: living systematic review and meta-analysis. BMJ. 2020 Sep 1;370:m3320. doi: 10.1136/bmj.m3320.

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Footnote 10

Birol Ilter P, Prasad S, Mutlu MA, Tekin AB, O'Brien P, von Dadelszen P, et al. Maternal and perinatal outcomes of SARS-CoV-2 infection in unvaccinated pregnancies during Delta and Omicron waves. Ultrasound Obstet Gynecol. 2022 Jul;60(1):96,102. doi: 10.1002/uog.24916.

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Footnote 11

Engjom HM, Ramakrishnan R, Vousden N, Bunch K, Morris E, Simpson N, et al. Severity of maternal SARS-CoV-2 infection and perinatal outcomes during the Omicron variant dominant period: UK Obstetric Surveillance System national cohort study. medRxiv. 2022 Mar 9. https://doi.org/10.1101/2022.03.07.22271699.

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Footnote 12

Adhikari EH, MacDonald L, SoRelle JA, Morse J, Pruszynski J, Spong CY. COVID-19 Cases and Disease Severity in Pregnancy and Neonatal Positivity Associated With Delta (B.1.617.2) and Omicron (B.1.1.529) Variant Predominance. JAMA. 2022 Apr 19;327(15):1500,1502. doi: 10.1001/jama.2022.4356.

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Footnote 13

Birol Ilter P, Prasad S, Berkkan M, Mutlu MA, Tekin AB, Celik E, et al. Clinical severity of SARS-CoV-2 infection among vaccinated and unvaccinated pregnancies during the Omicron wave. Ultrasound Obstet Gynecol. 2022 Apr;59(4):560,562. doi: 10.1002/uog.24893.

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Footnote 14

Dileep A, ZainAlAbdin S, AbuRuz S. Investigating the association between severity of COVID-19 infection during pregnancy and neonatal outcomes. Sci Rep. 2022 Feb 22;12(1):3024. doi: 10.1038/s41598-022-07093-8.

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Footnote 15

Edlow AG, Castro VM, Shook LL, Kaimal AJ, Perlis RH. Neurodevelopmental Outcomes at 1 Year in Infants of Mothers Who Tested Positive for SARS-CoV-2 During Pregnancy. JAMA Netw Open. 2022 Jun 1;5(6):e2215787. doi: 10.1001/jamanetworkopen.2022.15787.

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Footnote 16

COVID-19 Vaccination During Pregnancy In Ontario: December 14, 2020 to March 31, 2022 [Internet]. Ottawa (ON): BORN Ontario; 2022 [cited 2022 Jul 12]. Available from: https://www.bornontario.ca/en/whats-happening/resources/Documents/COVID-19-Vaccination-during-pregnancy-in-Ontario_Report_third-dose_FINAL.pdf.

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Footnote 17

COVID-19: latest safety data provide reassurance about use of mRNA vaccines during pregnancy [Internet]. Amsterdam (NL): European Medicines Agency; 2022 Jan 18 [cited 2022 July 11]. Available from: https://www.ema.europa.eu/en/news/covid-19-latest-safety-data-provide-reassurance-about-use-mrna-vaccines-during-pregnancy.

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Footnote 18

Olson C. COVID-19 vaccine safety in pregnancy: Updates from the v-safe COVID-19 vaccine pregnancy registry [Internet]. Atlanta (GA): Centers for Disease Control and Prevention (CDC); 2021 Sep 22 [cited 2022 Jul 12]. Available from: https://www.cdc.gov/vaccines/acip/meetings/downloads/slides-2021-09-22/09-COVID-Olson-508.pdf.

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Footnote 19

Shimabukuro TT, Kim SY, Myers TR, Moro PL, Oduyebo T, Panagiotakopoulos L, et al. Preliminary Findings of mRNA Covid-19 Vaccine Safety in Pregnant Persons. N Engl J Med. 2021 Jun 17;384(24):2273,2282. doi: 10.1056/NEJMoa2104983.

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Footnote 20

Lipkind HS, Vazquez-Benitez G, DeSilva M, Vesco KK, Ackerman-Banks C, Zhu J, et al. Receipt of COVID-19 Vaccine During Pregnancy and Preterm or Small-for-Gestational-Age at Birth - Eight Integrated Health Care Organizations, United States, December 15, 2020-July 22, 2021. MMWR Morb Mortal Wkly Rep. 2022 Jan 7;71(1):26,30. doi: 10.15585/mmwr.mm7101e1.

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Footnote 21

Prasad S, Kalafat E, Blakeway H, Townsend R, O'Brien P, Morris E, et al. Systematic review and meta-analysis of the effectiveness and perinatal outcomes of COVID-19 vaccination in pregnancy. Nat Commun. 2022 May 10;13(1):2414. doi: 10.1038/s41467-022-30052-w.

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Footnote 22

Goldshtein I, Steinberg DM, Kuint J, Chodick G, Segal Y, Shapiro Ben David S, et al. Association of BNT162b2 COVID-19 Vaccination During Pregnancy With Neonatal and Early Infant Outcomes. JAMA Pediatr. 2022 May 1;176(5):470,477. doi: 10.1001/jamapediatrics.2022.0001.

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Footnote 23

Kharbanda EO, Haapala J, DeSilva M, Vazquez-Benitez G, Vesco KK, Naleway AL, et al. Spontaneous Abortion Following COVID-19 Vaccination During Pregnancy. JAMA. 2021 Oct 26;326(16):1629,1631. doi: 10.1001/jama.2021.15494.

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Footnote 24

agnus MC, Gjessing HK, Eide HN, Wilcox AJ, Fell DB, Håberg SE. Covid-19 Vaccination during Pregnancy and First-Trimester Miscarriage. N Engl J Med. 2021 Nov 18;385(21):2008,2010. doi: 10.1056/NEJMc2114466.

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Footnote 25

Fell DB, Dhinsa T, Alton GD, Török E, Dimanlig-Cruz S, Regan AK, et al. Association of COVID-19 Vaccination in Pregnancy With Adverse Peripartum Outcomes. JAMA. 2022 Apr 19;327(15):1478,1487. doi: 10.1001/jama.2022.4255.

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Footnote 26

Magnus MC, Örtqvist AK, Dahlqwist E, Ljung R, Skår F, Oakley L, et al. Association of SARS-CoV-2 Vaccination During Pregnancy With Pregnancy Outcomes. JAMA. 2022 Apr 19;327(15):1469,1477. doi: 10.1001/jama.2022.3271.

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Footnote 27

Rose DU, Salvatori G, Dotta A, Auriti C. SARS-CoV-2 Vaccines during Pregnancy and Breastfeeding: A Systematic Review of Maternal and Neonatal Outcomes. Viruses. 2022 Mar 5;14(3):539. doi: 10.3390/v14030539.

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Footnote 28

Morgan JA, Biggio JR,Jr, Martin JK, Mussarat N, Chawla HK, Puri P, et al. Maternal Outcomes After Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection in Vaccinated Compared With Unvaccinated Pregnant Patients. Obstet Gynecol. 2022 Jan 1;139(1):107,109. doi: 10.1097/AOG.0000000000004621.

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Footnote 29

Ma Y, Deng J, Liu Q, Du M, Liu M, Liu J. Effectiveness and Safety of COVID-19 Vaccine among Pregnant Women in Real-World Studies: A Systematic Review and Meta-Analysis. Vaccines (Basel). 2022 Feb 6;10(2):246. doi: 10.3390/vaccines10020246.

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Footnote 30

de Freitas Paganoti C, Alkmin da Costa R, Papageorghiou AT, da Silva Costa F, Quintana SM, Graziela de Godoi L, et al. COVID-19 Vaccines Confer Protection in Hospitalized Pregnant and Postpartum Women with Severe COVID-19: A Retrospective Cohort Study. Vaccines (Basel). 2022 May 10;10(5):749. doi: 10.3390/vaccines10050749.

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Footnote 31

Yang YJ, Murphy EA, Singh S, Sukhu AC, Wolfe I, Adurty S, et al. Association of Gestational Age at Coronavirus Disease 2019 (COVID-19) Vaccination, History of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Infection, and a Vaccine Booster Dose With Maternal and Umbilical Cord Antibody Levels at Delivery. Obstet Gynecol. 2022 Mar 1;139(3):373,380. doi: 10.1097 / AOG.0000000000004693.

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Footnote 32

Atyeo C, Shook LL, Nziza N, Deriso EA, Muir C, Baez AM, et al. COVID-19 booster dose antibody response in pregnant, lactating, and nonpregnant women. medRxiv. 2022 May 19. https://doi.org/10.1101/2022.05.17.22275154.

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Footnote 33

Rottenstreich A, Zarbiv G, Oiknine-Djian E, Vorontsov O, Zigron R, Kleinstern G, et al. The effect of gestational age at BNT162b2 mRNA vaccination on maternal and neonatal SARS-CoV-2 antibody levels. Clin Infect Dis. 2022 Feb 16:ciac135. doi: 10.1093/cid/ciac135.

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Footnote 34

Munoz FM, Posavad CM, Richardson BA, Badell ML, Bunge K, Mulligan MJ, et al. COVID-19 booster vaccination during pregnancy enhances maternal binding and neutralizing antibody responses and transplacental antibody transfer to the newborn (DMID 21-0004). medRxiv. 2022 Jun 13. https://doi.org/10.1101/2022.06.13.22276354.

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Footnote 35

Carlsen EØ, Magnus MC, Oakley L, Fell DB, Greve-Isdahl M, Kinge JM, et al. Association of COVID-19 Vaccination During Pregnancy With Incidence of SARS-CoV-2 Infection in Infants. JAMA Intern Med. 2022 Jun 1:e222442. doi: 10.1001/jamainternmed.2022.2442.

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Footnote 36

Halasa NB, Olson SM, Staat MA, Newhams MM, Price AM, Pannaraj PS, et al. Maternal Vaccination and Risk of Hospitalization for Covid-19 among Infants. N Engl J Med. 2022 Jun 22. doi: 10.1056/NEJMoa2204399.

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Footnote 37

Badr DA, Picone O, Bevilacqua E, Carlin A, Meli F, Sibiude J, et al. Severe Acute Respiratory Syndrome Coronavirus 2 and Pregnancy Outcomes According to Gestational Age at Time of Infection. Emerg Infect Dis. 2021 Oct;27(10):2535,2543. doi: 10.3201/eid2710.211394.

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Footnote 38

Kugelman N, Nahshon C, Shaked-Mishan P, Cohen N, Lahav Sher M, Barsha H, et al. Third trimester messenger RNA COVID-19 booster vaccination upsurge maternal and neonatal SARS-CoV-2 immunoglobulin G antibody levels at birth. Eur J Obstet Gynecol Reprod Biol. 2022 Jul;274:148,154. doi: 10.1016/j.ejogrb.2022.05.029.

Return to footnote 38 referrer

Footnote 39

Rottenstreich A, Zarbiv G, Oiknine-Djian E, Vorontsov O, Zigron R, Kleinstern G, et al. Kinetics of maternally-derived anti- SARS-CoV-2 antibodies in infants in relation to the timing of antenatal vaccination. Clin Infect Dis. 2022 Jun 19:ciac480. doi: 10.1093/cid/ciac480.

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Footnote 40

Bender JM, Lee Y, Cheng WA, Marentes Ruiz CJ, Pannaraj PS. Coronavirus Disease 2019 Vaccine Booster Effects Are Seen in Human Milk Antibody Response. Front Nutr. 2022 May 24;9:898849. doi: 10.3389/fnut.2022.898849.

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Footnote 41

Esteve-Palau E, Gonzalez-Cuevas A, Guerrero ME, Garcia-Terol C, Alvarez MC, Garcia G, et al. Quantification and Progress Over Time of Specific Antibodies Against Severe Acute Respiratory Syndrome Coronavirus 2 in Breast Milk of Lactating Women Vaccinated With BNT162b2 Pfizer-BioNTech Coronavirus Disease 2019 Vaccine (LacCOVID). Open Forum Infect Dis. 2022 May 11;9(6):ofac239. doi: 10.1093/ofid/ofac239.

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Footnote 42

Perez SE, Luna Centeno LD, Cheng WA, Marentes Ruiz CJ, Lee Y, Congrave-Wilson Z, et al. Human Milk SARS-CoV-2 Antibodies up to 6 Months After Vaccination. Pediatrics. 2022 Feb 1;149(2):e2021054260. doi: 10.1542/peds.2021-054260.

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Footnote 43

Trofin F, Nastase EV, Iancu LS, Constantinescu D, Cianga CM, Lunca C, et al. Anti-RBD IgA and IgG Response and Transmission in Breast Milk of Anti-SARS-CoV-2 Vaccinated Mothers. Pathogens. 2022 Feb 24;11(3):286. doi: 10.3390/pathogens11030286.

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Footnote 44

Golan Y, Prahl M, Cassidy AG, Gay C, Wu AHB, Jigmeddagva U, et al. COVID-19 mRNA Vaccination in Lactation: Assessment of Adverse Events and Vaccine Related Antibodies in Mother-Infant Dyads. Front Immunol. 2021 Nov 3;12:777103. doi: 10.3389/fimmu.2021.777103.

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Footnote 45

Sajadi MM, Shokatpour N, Bathula A, Tehrani ZR, Lankford A, Purcell M, et al. Maternal transfer of IgA and IgG SARS-CoV-2 specific antibodies transplacentally and via breastfeeding. medRxiv. 2021 Dec 23. https://doi.org/10.1101/2021.12.21.21267733.

Return to footnote 45 referrer

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