Breastfeeding Mother and Child Clinical Outcomes After COVID-19 Vaccination

• Published in: Journal of human lactation Vol. 38; no. 1; pp. 37 - 42
• Main Authors: Low, Jia Ming, Lee, Le Ye, Ng, Yvonne Peng Mei, Zhong, Youjia, Amin, Zubair
• Format: Journal Article
• Language: English
• Published: Los Angeles, CA SAGE Publications 01-02-2022
• Subjects: BNT162 Vaccine; Breast Feeding; COVID-19; COVID-19 Vaccines; Female; Humans; Infant; Lactation; Mothers; mRNA Vaccines; Prospective Studies; SARS-CoV-2; Vaccination; Vaccines, Synthetic; COVID-19; mRNA vaccines; human milk; cohort study; breastfeeding; mastitis
• ISSN: 0890-3344; 1552-5732
• DOI: 10.1177/08903344211056522

Background:
Pre-approval clinical trials of the Pfizer/BioNTech messenger RNA COVID-19 vaccine, BNT162b2 did not include participants who were breastfeeding. Therefore, there is limited evidence about outcomes of breastfeeding mother–child dyads and effects on breastfeeding after vaccination.
Research Aims:
To determine: (1) solicited adverse effects (e.g., axillary lymphadenopathy, mastitis, and breast engorgement), which are unique to lactating individuals; and (2) systemic and local adverse effects of COVID-19 mRNA vaccine on mothers and potential effects on their breastfed infants.
Method:
This was a prospective cohort study of lactating healthcare workers (N = 88) in Singapore who received two doses of BNT162b2 vaccination (Pfizer/BioNTech). The outcomes of mother–child dyads within 28 days after the second vaccine dose were determined through a participant-completed questionnaire.
Results:
Minimal effects related to breastfeeding were reported by this cohort; three of 88 (3.4%) participants had mastitis, one (1.1%) participant experienced breast engorgement, five of 88 (5.7%) participants reported cervical or axillary lymphadenopathy. There was no change in human milk supply after vaccination. The most common side effect was pain/redness/swelling at the injection site, which was experienced by 57 (64.8%) participants. There were no serious adverse events of anaphylaxis or hospital admissions. There were no short-term adverse effects reported in the infants of 67 lactating participants who breastfed within 72 hr after BNT162b2 vaccination.
Conclusions:
BNT162b2 vaccination was well tolerated in lactating participants and was not associated with short-term adverse effects in their breastfed infants.
Study Protocol Registration:
The study protocol was registered at clinicaltrials.gov (NCT04802278).