Human Milk Antibodies after BNT162b2 Vaccination Exhibit Reduced Binding against SARS-CoV-2 Variants of Concern

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Human Milk Antibodies after BNT162b2 Vaccination Exhibit Reduced Binding against SARS-CoV-2 Variants of Concern
Title:
Human Milk Antibodies after BNT162b2 Vaccination Exhibit Reduced Binding against SARS-CoV-2 Variants of Concern
Other Titles:
Vaccines
Publication Date:
31 January 2022
Citation:
Low, Gu, Y., Ng, M. S. F., Wang, L. W., Amin, Z., Zhong, Y., & MacAry, P. A. (2022). Human Milk Antibodies after BNT162b2 Vaccination Exhibit Reduced Binding against SARS-CoV-2 Variants of Concern. Vaccines, 10(2), 225. https://doi.org/10.3390/vaccines10020225
Abstract:
SARS-CoV-2-specific antibody responses are engendered in human milk after BNT162b2 vaccination. However, the emergence of variants of concern (VOCs) raises concerns about the specificity of and potential cross-protection mediated by milk antibody responses, which are crucial for passive immunity transferred from breastfeeding mothers to their infants. In this study, we collected milk samples at three different time points pre- and post-vaccination, and measured milk IgA antibody binding to the receptor binding domain (RBD) of the original Wuhan-Hu-1 strain, and the four VOCs, namely Alpha, Beta, Gamma and Delta. We report a significant level of anti-RBD IgA in milk collected at 4–6 weeks after the second dose of vaccination compared to pre-vaccination. We observed around a 30% reduction in binding to most VOCs, including the major circulating Delta variant, compared to the original Wuhan-Hu-1 strain. As COVID-19 vaccines may take some time to be approved for infants, these individuals remain at risk for severe disease and rely mainly on transferred passive immunity. Our findings support the current recommendations for vaccinating lactating women with the aim of transferring mucosal immunity to breastfeeding infants.
License type:
Attribution 4.0 International (CC BY 4.0)
Funding Info:
This research / project is supported by the Khoo Teck Puat-National University Children’s Medical Institute (KTP—NUCMI) and NUS Yong Loo Lin School of Medicine - Pitch for Funds Grant
Grant Reference no. : NA

This research / project is supported by the National Medical Research Council / Ministry of Health - SARS-CoV-2 antibody initiative
Grant Reference no. : R-571-000-081-213

This research / project is supported by the National Medical Research Council / Ministry of Health - Reimagine Research Fund
Grant Reference no. : R-571-001-093-114
Description:
ISSN:
2076-393X