AUTHOR=Pace Ryan M. , Williams Janet E. , Järvinen Kirsi M. , Meehan Courtney L. , Martin Melanie A. , Ley Sylvia H. , Barbosa-Leiker Celestina , Andres Aline , Yeruva Laxmi , Belfort Mandy B. , Caffé Beatrice , Navarrete Alexandra D. , Lackey Kimberly A. , Pace Christina D. W. , Gogel Alexandra C. , Fehrenkamp Bethaney D. , Klein Miranda , Young Bridget E. , Rosen-Carole Casey , Diaz Nichole , Gaw Stephanie L. , Flaherman Valerie , McGuire Mark A. , McGuire Michelle K. , Seppo Antti E. TITLE=Milk From Women Diagnosed With COVID-19 Does Not Contain SARS-CoV-2 RNA but Has Persistent Levels of SARS-CoV-2-Specific IgA Antibodies JOURNAL=Frontiers in Immunology VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2021.801797 DOI=10.3389/fimmu.2021.801797 ISSN=1664-3224 ABSTRACT=Background

Limited data are available regarding the balance of risks and benefits from human milk and/or breastfeeding during and following maternal infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

Objective

To investigate whether SARS-CoV-2 can be detected in milk and on the breast after maternal coronavirus disease 2019 (COVID-19) diagnosis; and characterize concentrations of milk immunoglobulin (Ig) A specific to the SARS-CoV-2 spike glycoprotein receptor binding domain (RBD) during the 2 months after onset of symptoms or positive diagnostic test.

Methods

Using a longitudinal study design, we collected milk and breast skin swabs one to seven times from 64 lactating women with COVID-19 over a 2-month period, beginning as early as the week of diagnosis. Milk and breast swabs were analyzed for SARS-CoV-2 RNA, and milk was tested for anti-RBD IgA.

Results

SARS-CoV-2 was not detected in any milk sample or on 71% of breast swabs. Twenty-seven out of 29 (93%) breast swabs collected after breast washing tested negative for SARS-CoV-2. Detection of SARS-CoV-2 on the breast was associated with maternal coughing and other household COVID-19. Most (75%; 95% CI, 70-79%; n=316) milk samples contained anti-RBD IgA, and concentrations increased (P=.02) during the first two weeks following onset of COVID-19 symptoms or positive test. Milk-borne anti-RBD IgA persisted for at least two months in 77% of women.

Conclusion

Milk produced by women with COVID-19 does not contain SARS-CoV-2 and is likely a lasting source of passive immunity via anti-RBD IgA. These results support recommendations encouraging lactating women to continue breastfeeding during and after COVID-19 illness.