Detection of SARS-CoV-2 IgA and IgG in human milk and breastfeeding infant stool 6 months after maternal COVID-19 vaccination (preprint)

Objective: Assess the presence, durability, and neutralization capacity of SARS-CoV-2-specific antibodies in breastfeeding infants’ stools, mother’s plasma, and human milk following maternal vaccination. Design: Thirty-seven mothers and 25 infants were enrolled between December 2020 and November 2021 for this prospective observational study. Human milk, maternal plasma, and infants' stools were collected pre-vaccination and at periods up to 6 months following COVID-19 vaccine series initiation/completion. SARS-CoV-2 antibody levels and their neutralization capacities were assessed in collected samples. Results: SARS-CoV-2-specific IgA and IgG levels were higher in infant stool post-maternal vaccination amongst milk-fed compared to pre-COVID controls. Human milk and plasma SARS-CoV-2-specific IgA and IgG concentrations decreased over 6 months post-vaccination but remained higher than pre-vaccination levels. We observed improved neutralization capacity in milk antibodies over time. Conclusions: The presence of neutralizing SARS-CoV-2-specific antibodies in infant stool following maternal vaccination offers further evidence of the lasting transfer of these antibodies through breastfeeding and their protective effect.

Detection of SARS-CoV-2 specific IgA in the human milk of COVID-19 vaccinated, lactating health care workers (preprint)

Importance: In 2019, a deadly virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for COVID-19, emerged. In December 2020, two mRNA-based COVID-19 vaccines were approved for use in the United States (US) which provide immunity to those receiving the vaccine. Maternally derived antibodies are a key element of infants' immunity. Certain vaccines given to pregnant and lactating mothers provide immunity to infants through transmission across the placenta, umbilical cord (IgG) and human milk (IgA). Human milk produced by mothers with a history of COVID-19 infection contains SARS-CoV-2 IgA and IgG. Objective: To determine whether SARS-CoV-2 specific immunoglobulins are found in human milk after the COVID-19 vaccination, and to characterize the types of immunoglobulins present. Design, setting and participants: This is a prospective observational study conducted at Shands Hospital, University of Florida from December 2020 to March 2021. Twenty-two lactating healthcare workers who received the SARS-CoV-2 mRNA vaccine (Pfizer/BioNtech or Moderna) made up the sample group. Plasma and human milk were collected at three-time points (pre-vaccination, post first vaccine dose , and post-second vaccine dose). SARS-CoV-2 specific IgA and IgG in human milk and in plasma were measured by ELISA. Maternal demographics was compiled. Exposures: Pfizer/BioNtech or Moderna vaccination. Main outcome and measure: Levels of SARS-CoV-2 IgA and IgG in human milk and plasma. Results: We found significant secretion of SARS-CoV-2 specific IgA and IgG in human milk and plasma after SARS-CoV-2 vaccination. Conclusions and relevance: Our results show that the mRNA-based COVID-19 vaccines induce SARS-CoV-2 specific IgA and IgG secretion in human milk. Further studies are needed to determine the duration of this immune response, its capacity to neutralize the COVID-19 virus, the transfer of passive immunity to breastfeeding infants, and the potential therapeutic use of human milk IgA to combat SARS-Cov-2 infections and COVID-19.

Detection of SARS-CoV-2 Specific IgA in the Human Milk of COVID-19 Vaccinated, Lactating Health Care Workers (preprint)

Background: In 2019, a deadly virus known as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), responsible for COVID-19, emerged. In December 2020, two mRNA-based COVID-19 vaccines were approved for use in the United States (US) which provide immunity to those receiving the vaccine. Maternally derived antibodies are a key element of infants' immunity. Certain vaccines given to pregnant and lactating mothers provide immunity to infants through transmission across the placenta, umbilical cord (IgG) and human milk (IgA). Human milk produced by mothers with a history of COVID-19 infection contains SARS-CoV-2 IgA and IgG. The purpose of this study is to determine whether SARS-CoV-2 specific immunoglobulins are found in human milk after the COVID-19 vaccination, and to characterize the types of immunoglobulins present.Methods: This is a prospective observational study conducted at Shands Hospital, University of Florida from December 2020 to March 2021. Twenty-two lactating healthcare workers who received the SARS-CoV-2 mRNA vaccine (Pfizer/BioNtech or Moderna) made up the sample group. Plasma and human milk were collected at three-time points (pre-vaccination, post-first vaccine dose, and post-second vaccine dose). SARS-CoV-2 specific IgA and IgG in human milk and in plasma were measured by ELISA. Maternal demographics was compiled.Results: We found significant secretion of SARS-CoV-2 specific IgA and IgG in human milk and plasma after SARS-CoV-2 vaccination.Conclusions: Our results show that the mRNA-based COVID-19 vaccines induce SARS-CoV-2 specific IgA and IgG secretion in human milk. Further studies are needed to determine the duration of this immune response, its capacity to neutralize the COVID-19 virus, the transfer of passive immunity to breastfeeding infants, and the potential therapeutic use of human milk IgA to combat SARS-CoV-2 infections and COVID-19.Funding: Children’s Miracle Network.Conflict of Interest: There is no conflict of interest to disclose.Ethical Approval: This University of Florida IRB-approved (protocol #202003255).