The breadth and neutralizing activity of SARS-CoV-2 antibodies among children 6 months to 4 years of age following vaccination with mRNA-1273 or BNT162b2

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Presentation Time: 11:30 AM - 12:45 PM
Poster Board Number: B555
Abstract ID: 6118

Presenting Author:
Caitlin Williams , Postdoctoral Research Associate at Weill Cornell Med.

Abstract:

Body: The mRNA-based COVID-19 vaccines approved for use in children less than 5 years of age have differences that could affect vaccine immunogenicity and effectiveness. We directly compared the adaptive immune responses to mRNA-1273 or BNT162b2 in children under the age of 5.

Methods: We enrolled children 6 months to 4 years of age who completed primary series vaccination with monovalent mRNA-1273 or BNT162b2 vaccines between July and December 2022. Serum was collected from children one month after completion of the primary vaccine series. Children receiving either vaccine series developed robust and broad serum SARS-CoV-2-specific binding and neutralizing antibodies, including to Omicron subvariants. Children with a prior history of SARS-CoV-2 infection or who had detectable serum SARS-CoV-2 nucleocapsid antibodies at enrollment developed significantly higher antibody binding responses and neutralization. No differences in vaccine-induced antibody responses were observed between children 6-23 months of age and 24-59 months of age.

Conclusions: Monovalent mRNA-1273 and BNT162b2 elicit similar antibody responses one month after vaccination in young children irrespective of age. Prior infection significantly enhanced the strength of antibody responses to Omicron subvariants. These findings demonstrate that both mRNA-based COVID-19 vaccines induce immune correlates of protection from severe COVID-19 among young children.