SARS-CoV-2 IgG dominance and correlated viral neutralization after mRNA COVID-19 booster dose in plasma and human milk  

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Presentation Time: 11:30 AM - 12:45 PM
Poster Board Number: B553
Abstract ID: 5986

Presenting Author:
Joseph Larkin , Aso Professor at Univ. of Florida

Abstract:

The COVID-19 booster decreases infection risk and disease severity. Previously we found the initial mRNA COVID-19 vaccine regimen  increased SARS-CoV-2 IgA and IgG in milk and plasma, as well as viral neutralization. However, the contribution of SARS-CoV-2 booster is not known.   In our observational study, 33 mothers provided plasma and milk samples over the course of 12 months following mRNA COVID-19 vaccination, with 14 mothers receiving a booster dose between 6 and 12 months post initial vaccination.  We observed a significant increase in SARS-CoV-2 specific IgG in both milk and plasma following the booster dose compared to pre-vaccination, 7-30 days post second dose, and pre-booster.  We also found that In vitro neutralization of VSV-SARS-CoV-2-S-gp (BSL2 safe psuedovirus) improved following booster vaccination compared to pre-booster dose in both plasma and milk (by 90% and 55%, respectively). Increased SARS-CoV-2 IgG was found to be positively correlated with increased plasma and milk mediated neutralization. A recently published study has shown that increased SARS-CoV-2 IgG in blood is clinically correlated to disease protection, though there is still limited data on the clinical correlation of human milk antibody titers and infant protection. Further research exploring milk IgG is necessary for a better understanding of its role in infant health and protection.