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

Authors: PACE, RYAN - University Of Idaho; WILLIAMS, JANET - University Of Idaho; JÄRVINEN, KIRSI - University Of Rochester; MEEHAN, COURTNEY - Washington State University; MARTIN, MELANIE - University Of Washington; LEY, SYLVIA - Tulane University; BARBOSA-LEIKER, CELESTINA - Washington State University; ANDRES, ALINE - Arkansas Children'S Nutrition Research Center (ACNC); Yeruva, Laxmi; BELFORT, MANDY - Brigham & Women'S Hospital; CAFFE, BEATRICE - Washington State University; NAVARRETE, ALEXANDRA - Washington State University; LACKEY, KIMBERLY - University Of Idaho; PACE, CHRISTINA D.W. - University Of Idaho; GOGEL, ALEXANDRA - University Of Idaho; FEHRENKAMP, BETHANEY - University Of Idaho; KLEIN, MIRANDA - University Of Rochester; YOUNG, BRIDGET - University Of Rochester; ROSEN-CAROLE, CASEY - University Of Rochester; DIAZ, NICHOLE - University Of Rochester; GAW, STEPHANIE - University Of California; FLAHERMAN, VALERIE - University Of California; MCGUIRE, MARK - University Of Idaho; MCGUIRE, MICHELLE - University Of Idaho; SEPPO, ANTTI - University Of Rochester

Submitted to: Frontiers in Immunology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/6/2021
Publication Date: 12/23/2021
Citation: Pace, R.M., Williams, J.E., Järvinen, K.M., Meehan, C.L., Martin, M.A., Ley, S.H., Barbosa-Leiker, C., Andres, A., Yeruva, V., Belfort, M.B., Caffe, B., Navarrete, A.D., Lackey, K.A., Pace, C., Gogel, A.C., Fehrenkamp, B.D., Klein, M., Young, B., Rosen-Carole, C., Diaz, N., Gaw, S.L., Flaherman, V., Mcguire, M.A., Mcguire, M.K., Seppo, A. 2021. 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. Frontiers in Immunology. https://doi.org/10.3389/fimmu.2021.801797.
DOI: https://doi.org/10.3389/fimmu.2021.801797

Interpretive Summary: 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). The presence of virus and anti-viral antibodies in milk contribute to the balance of risks and benefits that breastfeeding provides to infants of mothers with SARS-CoV-2 infection. The primary objective of this study was to use validated analytical methods and optimized longitudinal sampling to analyze milk produced after maternal COVID-19 diagnosis for the presence of SARS-CoV-2, as well as levels and duration of milk-borne anti-RBD IgA for up to 2 months after diagnosis. We found no evidence of SARS-CoV-2 in milk and documented the presence of antigen specific (i.e., anti-RBD IgA) antibody that persisted for at least 2 months in milk produced by most study participants. Beyond the health impacts of human milk as a source of nutrition, these data suggest that, on balance, human milk is not a source of SARS-CoV-2 transmission and may provide lasting passive immunity. Our findings also provide additional support that lactating women with COVID-19 could continue to breastfeed while they and others in the household take precautions, such as hand and respiratory hygiene, to prevent transmission via respiratory droplets.

Technical Abstract: 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). 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. 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. 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 until two months in 77% of women. 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.