Development of Mucosal and Systemic Immunity and Risk of Food Allergy

Transmission of the SARS-CoV-2 virus in human milk (HM) is unknown with only 11poorly-described studies, reporting detectable virus in just 1 of the total 36 breastmilk samples. Further,it is possible that maternal SARS-CoV-2 infection during pregnancy and lactation confers some specificprotection through antibodies. Only one study reports the presence of IgG to SARS-CoV-2in HM. Alarming examples of antibody-dependent enhancement of other viral infections illustrate howcritical it is to understand both the profile and activity of these antibodies in HM. It is critical then tounderstand the transmission risks and protective factors between mother and child throughbreastfeeding.Design: We propose a longitudinal cohort study of COVID-19+ mothers to determine risks oftransmission (viral exposure of infants through breastfeeding by presence in HM and on areolar skin)and protective factors (SARS-CoV-2-specific antibody response in HM, profile and neutralizationcapacity) of breastfeeding. Longitudinal samples will allow us to assess temporal changes over diseasecourse.Methods: We will enroll 50 COVID+ mothers in the first 3 months of lactation, 25 symptomatic and 25asymptomatic. We will concurrently collect samples from two locations: The University of RochesterSchool of Medicine and Dentistry and New York University, NY. These sites will provide robust andstaggered access to patients. We will recruit through local hospitals and social media platforms. Motherswill provide informed eConsent. IRB approval has been received. All samples will be self-collected inthe hospital (if admitted) or in the home. There will be no physical contact between study staffand participants. Mothers will express and collect whole breastmilk on Days 0 (enrollment), 3, 10, 19,28, and 90, breast skin swabs on Days 0 and 3 and whole blood by fingerstick on days 0 and 90. Theywill also be instructed to provide a frozen HM sample from Day -7, if available.Analysis: RNA will be extracted from HM and breast skin swabs in the Jarvinen-Seppo lab. SARS-CoV-2 genomic RNA will be quantitated using RT-qPCR three amplicon probe-based systemas recommended by CDC. We will compare presence and changes in SARS-CoV-2 in HM via repeatedmeasures analysis. We will assess SARS-CoV-2 and other coronavirus antibodies in maternal fingerprick and HM to S and N proteins of SARS1, SARS2, HKU1, 229E, NL63 and OC43 by Luminex onthe mPLEX-CoV system developed and validated by the Zand lab. Repeated measures analysis will beused to compare the changes in concentration of HM anti-SARS-CoV-2 antibodies over the time-courseof disease progression and also between women with mild to severe symptoms.Impact: These results are critical to understand the risks and benefits of breastfeeding in the context ofCOVID-19 infection, and are necessary to make evidence-based policies, and to care for these families.