Characterization of SARS-CoV-2 RNA, Antibodies, and Neutralizing Capacity in Milk Produced by Women with COVID-19
Top Cited Papers
Open Access
- 23 February 2021
- journal article
- research article
- Published by American Society for Microbiology in mBio
- Vol. 12 (1)
- https://doi.org/10.1128/mbio.03192-20
Abstract
Whether mother-to-infant SARS-CoV-2 transmission can occur during breastfeeding and, if so, whether the benefits of breastfeeding outweigh this risk during maternal COVID-19 illness remain important questions. Using RT-qPCR, we did not detect SARS-CoV-2 RNA in any milk sample (n = 37) collected from 18 women following COVID-19 diagnosis. Although we detected evidence of viral RNA on 8 out of 70 breast skin swabs, only one was considered a conclusive positive result. In contrast, 76% of the milk samples collected from women with COVID-19 contained SARS-CoV-2-specific IgA, and 80% had SARS-CoV-2-specific IgG. In addition, 62% of the milk samples were able to neutralize SARS-CoV-2 infectivity in vitro, whereas milk samples collected prior to the COVID-19 pandemic were unable to do so. Taken together, our data do not support mother-to-infant transmission of SARS-CoV-2 via milk. Importantly, milk produced by infected mothers is a beneficial source of anti-SARS-CoV-2 IgA and IgG and neutralizes SARS-CoV-2 activity. These results support recommendations to continue breastfeeding during mild-to-moderate maternal COVID-19 illness. IMPORTANCE Results from prior studies assaying human milk for the presence of SARS-CoV-2, the causative virus of COVID-19, have suggested milk may act as a potential vehicle for mother-to-child transmission. Most previous studies are limited because they followed only a few participants, were cross-sectional, and/or failed to report how milk was collected and/or analyzed. As such, considerable uncertainty remains regarding whether human milk is capable of transmitting SARS-CoV-2 from mother to child. Here, we report that repeated milk samples collected from 18 women following COVID-19 diagnosis did not contain SARS-CoV-2 RNA; however, risk of transmission via breast skin should be further evaluated. Importantly, we found that milk produced by infected mothers is a source of anti-SARS-CoV-2 IgA and IgG and neutralizes SARS-CoV-2 activity. These results support recommendations to continue breastfeeding during mild-to-moderate maternal COVID-19 illness as milk likely provides specific immunologic benefits to infants.Keywords
Funding Information
- Washington State University Health Equity Research Center
- University of Idaho Agricultural Experiment Station
- HHS | National Institutes of Health (R01 HD092297-03, U01 AI131344-04S1)
- Bill and Melinda Gates Foundation
This publication has 39 references indexed in Scilit:
- Timing of initiation, patterns of breastfeeding, and infant survival: prospective analysis of pooled data from three randomised trialsThe Lancet. Global Health, 2016
- Association of HIV-1 Envelope-Specific Breast Milk IgA Responses with Reduced Risk of Postnatal Mother-to-Child Transmission of HIV-1Journal of Virology, 2015
- Association of Timing of Initiation of Breastmilk Expression on Milk Volume and Timing of Lactogenesis Stage II Among Mothers of Very Low-Birth-Weight InfantsBreastfeeding Medicine, 2015
- Breastfeeding and the Use of Human MilkPEDIATRICS, 2012
- HIV-Specific Functional Antibody Responses in Breast Milk Mirror Those in Plasma and Are Primarily Mediated by IgG AntibodiesJournal of Virology, 2011
- Delayed Breastfeeding Initiation Increases Risk of Neonatal MortalityPEDIATRICS, 2006
- Immunologic Factors in Human Milk: The Effects of Gestational Age and PasteurizationJournal of Human Lactation, 2005
- Assignment of Weight-Based Antibody Units for 13 Serotypes to a Human Antipneumococcal Standard Reference Serum, Lot 89-S(F)Clinical and Vaccine Immunology, 2004
- Breastmilk RNA viral load in HIV-infected South African womenAIDS, 2003
- Milk cytokines and subclinical breast inflammation in Tanzanian women: effects of dietary red palm oil or sunflower oil supplementationImmunology, 1999