Search

Completion of a COVID-19 vaccination series during pregnancy effectively reduces COVID-19 hospitalization among infants less than 6 months of age. The dynamics of transplacental transfer of maternal vaccine-induced antibodies, and their persistence in infants at 2, 6, 9, and 12 months, have implications for new vaccine development and optimal timing of vaccine administration in pregnancy. We evaluated anti-COVID antibody IgG subclass, Fc-receptor binding profile, and activity against wild-type Spike and RBD plus five variants of concern (VOCs) in 153 serum samples from 100 infants. Maternal IgG1 and IgG3 responses persisted in 2- and 6-month infants to a greater extent than the other IgG subclasses, with high persistence of antibodies binding placental neonatal Fc-receptor and FcγR3A. Lowest persistence was observed against the Omicron RBD-specific region. Maternal vaccine timing, placental Fc-receptor binding capabilities, antibody subclass, fetal sex, and VOC all impact the persistence of antibodies in infants through 12 months of age., Competing Interests: The opinions expressed in this paper are those of the authors and do not necessarily represent those of Merck Sharp & Dohme Corp. K.J.G. has consulted for Illumina, BillionToOne, and Aetion outside the scope of the submitted work. A.G.E. and M.A.E. serve as medical advisors for Mirvie. M.A.E. has equity in Mirvie outside the submitted work. B.D.J. is a part time employee of Leyden Laboratories B.V., Netherlands. B.D.J.’s immediate family member, Galit Alter, is a co-founder of SeromYx Systems, Inc., and has a patent on Systems Serology Platform pending., (© 2024 The Authors.)