NYMC Faculty Publications

SARS-Cov-2 Antibodies and Their Neutralizing Capacity Against Live Virus in Human Milk After COVID-19 Infection and Vaccination: Prospective Cohort Studies

Samantha Ismail, Department of Nutritional Sciences, University of Toronto, Toronto, Canada.
Sharon Unger, Department of Nutritional Sciences, University of Toronto, Toronto, Canada; Rogers Hixon Ontario Human Milk Bank, Sinai Health System, Toronto, Canada; Paediatrics, Sinai Health System, Toronto, Canada.
Patrick Budylowski, Combined Containment Level 3 Unit, University of Toronto, Toronto, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Canada.
Susan Poutanen, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Microbiology, Sinai Health System/University Health Network, Toronto, Canada.
Yvonne Yau, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; The Hospital for Sick Children Research Institute, Toronto, Canada; Department of Paediatric Laboratory Medicine, The Hospital for Sick Children, Toronto, Canada.
Carleigh Jenkins, Department of Nutritional Sciences, University of Toronto, Toronto, Canada; Rogers Hixon Ontario Human Milk Bank, Sinai Health System, Toronto, Canada.
Shaista Anwer, Department of Microbiology, Sinai Health System/University Health Network, Toronto, Canada.
Natasha Christie-Holmes, Combined Containment Level 3 Unit, University of Toronto, Toronto, Canada.
Alex Kiss, Evaluative Clinical Sciences, Sunnybrook Research Institute, Toronto, Canada; Institute of Health Policy Management and Evaluation, University of Toronto, Toronto, Canada.
Tony Mazzulli, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Microbiology, Sinai Health System/University Health Network, Toronto, Canada.
Jennie Johnstone, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Microbiology, Sinai Health System/University Health Network, Toronto, Canada.
Allison McGeer, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada; Department of Microbiology, Sinai Health System/University Health Network, Toronto, Canada.
Wendy Whittle, Obstetrics and Gynecology, Sinai Health System, Toronto, Canada.
Boriana Parvez, New York Medical College, Valhalla, United States.
Scott D. Gray-Owen, Combined Containment Level 3 Unit, University of Toronto, Toronto, Canada; Department of Molecular Genetics, University of Toronto, Toronto, Canada.
Debbie Stone, Rogers Hixon Ontario Human Milk Bank, Sinai Health System, Toronto, Canada.
Deborah L. O'Connor, Department of Nutritional Sciences, University of Toronto, Toronto, Canada; Rogers Hixon Ontario Human Milk Bank, Sinai Health System, Toronto, Canada; Paediatrics, Sinai Health System, Toronto, Canada; The Hospital for Sick Children Research Institute, Toronto, Canada. Electronic address: deborah.oconnor@utoronto.ca.

Author Type(s)

Faculty

Journal Title

The American Journal of Clinical Nutrition

First Page

485

Last Page

495

Document Type

Article

Publication Date

2-1-2024

Department

Pediatrics

Abstract

BACKGROUND: There is limited understanding of the impact of coronavirus disease 2019 (COVID-19) infection and vaccination type and interval on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) human milk antibodies and their neutralizing capacity. OBJECTIVES: These cohort studies aimed to determine the presence of antibodies and live virus neutralizing capacity in milk from females infected with COVID-19, unexposed milk bank donors, and vaccinated females and examine impacts of vaccine interval and type. METHODS: Milk was collected from participants infected with COVID-19 during pregnancy or lactation (Cohort-1) and milk bank donors (Cohort-2) from March 2020-July 2021 at 3 sequential 4-wk intervals and COVID-19 vaccinated participants with varying dose intervals (Cohort-3) (January-October 2021). Cohort-1 and Cohort-3 were recruited from Sinai Health (patients) and through social media. Cohort-2 included Ontario Milk Bank donors. Milk was examined for SARS-CoV-2 antibodies and live virus neutralization. RESULTS: Of females with COVID-19, 53% (Cohort-1, n = 55) had anti-SARS-CoV-2 IgA antibodies in ≥1 milk sample. IgA+ samples (40%) were more likely neutralizing than IgA- samples (odds ratio [OR]: 2.18; 95% confidence interval [CI]: 1.03, 4.60; P = 0.04); however, 25% of IgA- samples were neutralizing. Both IgA positivity and neutralization decreased ∼6 mo after symptom onset (0-100 compared with 201+ d: IgA OR: 14.30; 95% CI: 1.08, 189.89; P = 0.04; neutralizing OR: 4.30; 95% CI: 1.55, 11.89; P = 0.005). Among milk bank donors (Cohort-2, n = 373), 4.3% had IgA antibodies; 23% of IgA+ samples were neutralizing. Vaccination (Cohort-3, n = 60) with mRNA-1273 and shorter vaccine intervals (3 to <6 wk) resulted in higher IgA and IgG than BNT162b2 (P < 0.04) and longer intervals (6 to <16 wk) (P≤0.02), respectively. Neutralizing capacity increased postvaccination (P = 0.04) but was not associated with antibody positivity. CONCLUSIONS: SARS-CoV-2 infection and vaccination (type and interval) impacted milk antibodies; however, antibody presence did not consistently predict live virus neutralization. Although human milk is unequivocally the best way to nourish infants, guidance on protection to infants following maternal infection/vaccination may require more nuanced messaging. This study was registered at clinicaltrials.gov as NCT04453969 and NCT04453982.

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