Preserved recognition of Omicron Spike following COVID-19 mRNA vaccination in pregnancy
Abstract
Background
SARS-CoV-2 infection is associated with enhanced disease severity in pregnant women. Despite the potential of COVID-19 vaccines to reduce severe disease, vaccine uptake remained relatively low among pregnant women. Just as coordinated messaging from the CDC and leading obstetrics organizations began to increase vaccine confidence in this vulnerable group, the evolution of SARS-CoV-2 variants of concerns (VOC) including the Omicron VOC raised new concerns about vaccine efficacy, given their ability to escape vaccine-induced neutralizing antibodies. Early data point to a milder disease course following omicron VOC infection in vaccinated individuals. Thus, these data suggest that alternate vaccine induced immunity, beyond neutralization, may continue to attenuate omicron disease, such as antibody-Fc-mediated activity. However, whether vaccine induced antibodies raised in pregnancy continue to bind and leverage Fc-receptors remains unclear.
Methods
VOC including Omicron receptor binding domain (RBD) or full Spike specific antibody isotype binding titers and FcγR binding were analyzed in pregnant women after the full dose regimen of either Pfizer/BioNtech BNT62b2 (n=10) or Moderna mRNA-1273 (n=10) vaccination using a multiplexing Luminex assay.
Findings
Comparable, albeit reduced, isotype recognition was observed to the Omicron Spike and receptor binding domain (RBD) following both vaccines. Yet, despite the near complete loss of Fc-receptor binding to the Omicron RBD, Fc-receptor binding was largely preserved to the Omicron Spike.
Interpretation
Reduced binding titer to the Omicron RBD aligns with observed loss of neutralizing activity. Despite the loss of neutralization, preserved Omicron Spike recognition and Fc-receptor binding potentially continues to attenuate disease severity in pregnant women.
Funding
NIH and the Bill and Melinda Gates Foundation
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