Reactogenicity of mRNA- and Non-mRNA-Based COVID-19 Vaccines among Lactating Mother and Child Dyads

Short term Outcomes of COVID-19 Vaccines Among Lactating Mother and Child Dyads in Bangladesh: A Multi-centre, Cross-sectional Study

INTRODUCTION

The aims of the study are to: (1) determine the short-term reactogenicity of WHO-approved COVID-19 vaccines (i.e., Pfizer-BioNTech, Moderna, Sinovac, Oxford-AstraZeneca, Johnson and Johnson, Covaxin) amongst lactating women and their children, and 2) evaluate lactation-related outcomes following the same vaccines in Bangladesh.

METHODS

This was a multi-centre, self-reported, cross-sectional study of lactating woman-child dyads in Bangladesh. Demographics, past medical history, breastfeeding history and clinical outcomes of lactating woman-child dyads at least 7 days after the last dose of vaccine were determined through a structured questionnaire.

RESULTS

There were 750 participants from four centres. The mean age of lactating women and children surveyed were 27.6 (SD ± 4.6) years and 10.3 (SD ± 6.7) months, respectively. Majority (81.2%; 608 of 750) received 2 doses of COVID-19 vaccinations while lactating. Almost all (99.9%; 749 of 750) vaccinated lactating women surveyed reported no change in human milk supply. More than half of the participants (56.9%; 373 of 656) reported no symptoms after both doses of COVID-19 vaccines. There were no serious adverse events such as anaphylaxis or hospital admission. Majority of the lactating women (98.9%; 742 of 750) reported that the children whom they breastfed had no symptoms such as fever or cough.

DISCUSSION

This large study of lactating woman-child dyads in Bangladesh, who received a diverse range of WHO-approved COVID-19 vaccines, showed no serious short-term adverse effects.

The importance of COVID-19 vaccination during lactation

The World Health Organization strongly supports breastfeeding as the main source of infant feeding to ensure maternal and child health. Since its emergence, COVID-19 has become a disease affecting the health of the world's population, and vaccines have been developed to prevent it. However, the decision to license COVID-19 vaccines for infants under 6 months of age has been delayed. Different studies have shown that during the breastfeeding period, the benefit-risk balance is much higher in favor of the benefit, at the immunological level for the infant, due to its low perception of adverse effects and the low transmission of products such as mRNA from the mother to the child. Different organizations and societies recommend vaccination in breastfeeding women. COVID-19 vaccines have been shown to be safe and effective.

Safety and Efficacy of Coronavirus Disease 2019 (COVID-19) mRNA Vaccines During Lactation

In this review, we summarize the data on the safety and side-effect profile of coronavirus disease 2019 (COVID-19) vaccines during lactation to date, review what is known about mRNA vaccine components in breast milk, and discuss the efficacy of COVID-19 vaccines in providing immune protection for the breastfeeding infant. The Centers for Disease Control and Prevention and the American College of Obstetricians and Gynecologists recommend that lactating individuals receive COVID-19 mRNA vaccines and stay up to date on booster doses, including the bivalent COVID-19 booster. The lack of serious side effects in mothers or infants across numerous large studies and registries of COVID-19 vaccination in pregnancy and lactation is reassuring. Although small quantities of mRNA may be transiently detectable in breast milk after maternal vaccination, there are no data demonstrating that vaccine mRNA can survive the infant gastrointestinal tract and no evidence that breast milk from lactating individuals who have received a COVID-19 mRNA vaccine can cause harm to breastfeeding infants. In contrast, numerous studies demonstrate that the breast milk of vaccinated individuals contains severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-specific functional antibodies and T cells, which benefit the breastfeeding infant's developing immune system. Transfer of SARS-CoV-2-specific antibodies from mother to infant is highest when vaccination occurs during pregnancy compared with lactation, because the breastfeeding infant receives both long-lasting antibodies through the placenta and breast-milk antibodies through breast milk. With clear data demonstrating efficacy and safety and no data demonstrating harm to mother or infant after COVID-19 vaccine administration during lactation, any recommendations to avoid vaccination while breastfeeding or to withhold breast milk from the infant for any period of time after vaccination are not supported by available evidence.