{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T16:53:50Z","timestamp":1785430430253,"version":"3.56.0"},"reference-count":50,"publisher":"MDPI AG","issue":"12","license":[{"start":{"date-parts":[[2026,6,10]],"date-time":"2026-06-10T00:00:00Z","timestamp":1781049600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000071","name":"NICHD","doi-asserted-by":"publisher","award":["R21HD107761"],"award-info":[{"award-number":["R21HD107761"]}],"id":[{"id":"10.13039\/100000071","id-type":"DOI","asserted-by":"publisher"}]},{"award":["R21HD107761"],"award-info":[{"award-number":["R21HD107761"]}],"id":[{"id":"https:\/\/ror.org\/04byxyr05","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["JCM"],"abstract":"<jats:p>Background\/Objectives: In the first months of their life, infants rely on maternal antibodies for immune protection. Breastmilk is a major source of these defenses, supplying secretory IgA, IgG, and IgM that help guard mucosal surfaces against pathogens such as SARS-CoV-2. Most studies on breastmilk immunity in the context of COVID-19 have emphasized circulating monomeric IgA, rather than the multimeric secretory IgA (sIgA) that is active at mucosal barriers. This study assessed in-depth the contribution of breastmilk antibody subtypes to SARS-CoV-2 neutralization capacity and how these profiles differ following maternal COVID-19 infection versus vaccination during pregnancy or postpartum. Methods: In this prospective cohort study, breastmilk samples were collected longitudinally from individuals who had COVID-19 during pregnancy or received COVID-19 mRNA vaccination during pregnancy or postpartum. Serological assays measured IgG, IgM, systemic IgA, and secretory IgA against SARS-CoV-2 spike and nucleocapsid antigens. Results: COVID-19 infection during pregnancy resulted in significantly higher systemic and secretory IgA levels compared to vaccination. Secretory IgA demonstrated a strong correlation with neutralization capacity. Principal component analysis revealed distinct antibody profiles in COVID-19-exposed individuals versus vaccinated cohorts, with significant overlap between pregnancy and postpartum vaccination groups. Conclusions: Although both COVID-19 vaccination and disease elicit sustained COVID-19-related antibodies in breastmilk, COVID-19 infection elicits a broader and more diverse antibody response in breastmilk, specifically with a greater secretory IgA generation. These findings support the value of maternal vaccination to safely confer mucosal immunity to neonates and the need for optimized vaccine formulations for mucosal immunity.<\/jats:p>","DOI":"10.3390\/jcm15124494","type":"journal-article","created":{"date-parts":[[2026,6,11]],"date-time":"2026-06-11T02:59:31Z","timestamp":1781146771000},"page":"4494","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Impact of Maternal COVID-19 Infection Versus Vaccination on Mucosal Immunity in Breastmilk"],"prefix":"10.3390","volume":"15","author":[{"ORCID":"https:\/\/orcid.org\/0009-0002-8612-1825","authenticated-orcid":false,"given":"Mymy","family":"Nguyen","sequence":"first","affiliation":[{"name":"Department of Obstetrics and Gynecology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rupsa C.","family":"Boelig","sequence":"additional","affiliation":[{"name":"Department of Obstetrics and Gynecology, Thomas Jefferson University Hospital, Philadelphia, PA 19107, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Julie","family":"Jones","sequence":"additional","affiliation":[{"name":"Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA 19107, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0009-0009-4007-2504","authenticated-orcid":false,"given":"Wathsala","family":"Wijayalath","sequence":"additional","affiliation":[{"name":"Agile Vaccines and Therapeutics Department, Naval Medical Research Command (NMRC), Silver Spring, MD 20910, USA"},{"name":"Henry M Jackson Foundation for Advancement of Military Medicine, Inc., Bethesda, MD 20817, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gregory D.","family":"Gromowski","sequence":"additional","affiliation":[{"name":"Viral Diseases Branch, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-5545-9706","authenticated-orcid":false,"given":"Zubair H.","family":"Aghai","sequence":"additional","affiliation":[{"name":"Nemours Children\u2019s Health, Philadelphia, PA 19107, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8571-8956","authenticated-orcid":false,"given":"Elke S.","family":"Bergmann-Leitner","sequence":"additional","affiliation":[{"name":"Biologics Research & Development, Walter Reed Army Institute of Research, Silver Spring, MD 20910, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2026,6,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1486","DOI":"10.1016\/j.cell.2021.02.031","article-title":"The multifaceted roles of breast milk antibodies","volume":"184","author":"Atyeo","year":"2021","journal-title":"Cell"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"S154","DOI":"10.1093\/infdis\/jiac120","article-title":"Respiratory Syncytial Virus Is the Leading Cause of United States Infant Hospitalizations, 2009\u20132019: A Study of the National (Nationwide) Inpatient Sample","volume":"226","author":"Suh","year":"2022","journal-title":"J. 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