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. 2024 Mar 1;153(3):e2023064252.
doi: 10.1542/peds.2023-064252.

Maternal COVID-19 Vaccination and Prevention of Symptomatic Infection in Infants

Cristina V Cardemil  1 , Yi Cao  2 , Christine M Posavad  2 , Martina L Badell  3 , Katherine Bunge  4 , Mark J Mulligan  5 , Lalitha Parameswaran  5 , Courtney Olson-Chen  6 , Richard M Novak  7 , Rebecca C Brady  8 , Emily DeFranco  8 , Jeffrey S Gerber  9 , Marcela Pasetti  10 , Mallory Shriver  10 , Rhea Coler  11 , Bryan Berube  11 , Mehul S Suthar  12 , Alberto Moreno  12 , Fei Gao  2 , Barbra A Richardson  13 , Richard Beigi  4 , Elizabeth Brown  13 , Kathleen M Neuzil  10 , Flor M Munoz  14 ; MOMI-Vax Study Group
Affiliations

Maternal COVID-19 Vaccination and Prevention of Symptomatic Infection in Infants

Cristina V Cardemil et al. Pediatrics. .

Abstract

Background and objectives: Maternal vaccination may prevent infant coronavirus disease 2019 (COVID-19). We aimed to quantify protection against infection from maternally derived vaccine-induced antibodies in the first 6 months of an infant's life.

Methods: Infants born to mothers vaccinated during pregnancy with 2 or 3 doses of a messenger RNA COVID-19 vaccine (nonboosted or boosted, respectively) had full-length spike (Spike) immunoglobulin G (IgG), pseudovirus 614D, and live virus D614G, and omicron BA.1 and BA.5 neutralizing antibody (nAb) titers measured at delivery. Infant severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection was determined by verified maternal-report and laboratory confirmation through prospective follow-up to 6 months of age between December 2021 and July 2022. The risk reduction for infection by dose group and antibody titer level was estimated in separate models.

Results: Infants of boosted mothers (n = 204) had significantly higher Spike IgG, pseudovirus, and live nAb titers at delivery than infants of nonboosted mothers (n = 271), and were 56% less likely to acquire infection in the first 6 months (P = .03). Irrespective of boost, for each 10-fold increase in Spike IgG titer at delivery, the infant's risk of acquiring infection was reduced by 47% (95% confidence interval 8%-70%; P = .02). Similarly, a 10-fold increase in pseudovirus titers against Wuhan Spike, and live virus nAb titers against D614G, and omicron BA.1 and BA.5 at delivery were associated with a 30%, 46%, 56%, and 60% risk reduction, respectively.

Conclusions: Higher transplacental binding and nAb titers substantially reduced the risk of SARS-CoV-2 infection in infants, and a booster dose amplified protection during a period of omicron predominance. Until infants are age-eligible for vaccination, maternal vaccination provides passive protection against symptomatic infection during early infancy.

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Conflict of interest statement

CONFLICT OF INTEREST DISCLOSURES: Dr Badell conducts laboratory research and clinical trials with contract funding for vaccines or monoclonal antibodies versus severe acute respiratory syndrome coronavirus 2 with Lilly, Pfizer, and Sanofi, and receives personal fees for scientific advisory board service from Merck, Meissa Vaccines, Inc, and Pfizer. Dr Novak is a paid advisor to Gilead and an investigator on National Institutes of Health (NIH)-funded trials of Moderna, Pfizer, and Janssen vaccines. Dr Brady receives research grant support for clinical trials from PATH, Astra Zeneca, and Pfizer, on which she serves as coinvestigator. Dr Berube owns shares in HDT Bio Corp. Dr Suthar served as an advisor for Moderna (ended December 2021) and is currently serving as an advisor for Ocugen, Inc. Dr Richardson currently holds a position on a data and safety monitoring board for clinical trials at Gilead Sciences, Inc. Dr Neuzil is a member of the World Health Organization’s Strategic Advisory Group of Experts on Immunization, serves as coinvestigator on an NIH contract for a Vaccine Treatment and Evaluation Unit, serves as cochair of the NIH Coronavirus Disease 2019 (COVID-19) Prevention Network, and served as an investigator for phase I/II Pfizer COVID-19 vaccine grant, with a grant to the institution, but no salary support. Dr Neuzil receives grants from Pfizer to conduct clinical trials of COVID-19 vaccines through the Center for Vaccine Development and Global Health at the University of Maryland, Baltimore. She receives grants from NIH to participate in overall organization of COVID-19 vaccine trials and for participation in vaccine trials. Dr Munoz is an investigator of pediatric studies of COVID-19 vaccines for Pfizer and for a pediatric remdesivir study conducted by Gilead Sciences, Inc; serves as investigator on projects supported by an NIH contract for a Vaccine Treatment and Evaluation Unit; serves as member of the data safety monitoring board for clinical trials conducted by Pfizer, Moderna, Meissa Vaccines, Virometix, and the NIH; is a member of the American Academy of Pediatrics Section of Infectious Diseases and the Immunization Expert Group of the American College of Obstetrics and Gynecology; and is chair of the CEPI-funded Safety Platform for Emergency Vaccines Maternal Immunization Working Group.

Figures

FIGURE 1
FIGURE 1
COVID-19 incidence rate per 100 person-years within a calendar month (above each bar) and overall (top of each panel) from December 2021 to July 2022 stratified by infant’s age (A) and maternal COVID-19 boost (B). Within each bar, the number of incident infections in that month is listed, separated by a slash (/) next to the total person-years at risk within that month.
FIGURE 2
FIGURE 2
Smoothed estimate of the relationship between time since last COVID-19 vaccine dose and infant antibody titer at delivery by maternal boost status (left panel), and a boxplot of infant antibody titers at delivery stratified by maternal boost status (right panel). (A) anti-Spike IgG titers, (B) pseudovirus nAb titers, (C) live virus nAb titers for D614G, (D) live virus nAb for omicron BA.1, and (E) live virus nAb for omicron BA.5. The lower limit of quantitation (LLOQ) for the live virus neutralization assay (focus reduction neutralization titer) is 20; samples that do not neutralize at the limit of quantitation are assigned a value that is 1/2 of the LLOQ or 10. Samples with titers <20 are interpreted as not detected.
FIGURE 3
FIGURE 3
Antibody titers in infants at delivery after maternal COVID-19 booster dose during pregnancy, by maternal gestational age at booster dose in weeks. Cohort is limited to mothers without SARS-CoV-2 infection during pregnancy and who completed a booster at least 14 days before delivery. (A) Anti-Spike IgG titers, (B) pseudovirus nAb titers, (C) live virus nAb titers for D614G, (D) live virus nAb for omicron BA.1, and (E) live virus nAb for omicron BA.5. The lower limit of quantitation (LLOQ) for the live virus neutralization assay (focus reduction neutralization titer) is 20; samples that do not neutralize at the limit of quantitation are assigned a value that is 1/2 of the LLOQ or 10. Samples with titers <20 are interpreted as not detected.
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