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. 2024 Jan 2;7(1):e2352387.
doi: 10.1001/jamanetworkopen.2023.52387.

Timing of Maternal COVID-19 Vaccine and Antibody Concentrations in Infants Born Preterm

Alisa Kachikis  1 , Mindy Pike  1 , Linda O Eckert  1   2 , Emma Roberts  3 , Yael Frank  4 , Amber L Young  1 , Erin Goecker  5 , Michael G Gravett  1   2 , Alexander L Greninger  5 , Janet A Englund  6
Affiliations

Timing of Maternal COVID-19 Vaccine and Antibody Concentrations in Infants Born Preterm

Alisa Kachikis et al. JAMA Netw Open. .

Abstract

Importance: COVID-19 vaccine-derived antibodies in pregnant people may protect infants from severe infection in the first 6 months of life via transplacental antibody transfer. Few data exist on maternally derived SARS-CoV-2 antibodies in preterm compared with full-term infants in association with vaccination timing.

Objective: To compare SARS-CoV-2 anti-Spike (anti-S) antibody levels in preterm and full-term infants in the context of vaccine dose timing before delivery.

Design, setting, and participants: This prospective cohort study enrolled pregnant individuals and collected paired maternal and cord blood samples at delivery at the University of Washington between February 1, 2021, and January 31, 2023. Participants who had received at least 2 doses of a messenger RNA COVID-19 vaccine before delivery and did not have a history of prior COVID-19 infection or detectable anti-SARS-CoV-2 nucleocapsid antibodies were included.

Exposures: Timing of the last vaccine dose and preterm or full-term gestational age at delivery.

Main outcomes and measures: Paired maternal and cord samples were tested for anti-S antibody, and linear regression was used to evaluate associations between preterm delivery and anti-S antibody levels. Covariates included timing of last dose, number of doses, insurance status, and immunosuppressing medications.

Results: A total of 220 participants (median [IQR] age, 34 [32-37] years; 212 [96.4%] female) with 36 preterm and 184 full-term deliveries were studied. Before delivery, 121 persons received 2 vaccine doses and 99 persons received 3 or more vaccine doses. The geometric mean concentration of maternal anti-S antibodies was 674 (95% CI, 577-787) after 2 doses and 8159 (95% CI, 6636-10 032) after 3 or more doses (P < .001). The cord anti-S antibody geometric mean concentration was 1000 (95% CI, 874-1144) after 2 doses and 9992 (95% CI, 8381-11 914) after 3 or more doses (P < .001). After adjustment for vaccine timing and number of doses before delivery, no association was found between preterm delivery and cord anti-S antibody levels (β = 0.44; 95% CI, -0.06 to 0.94).

Conclusions and relevance: In this prospective cohort study of pregnant individuals with preterm and full-term deliveries, receipt of 3 or more compared with 2 doses of COVID-19 vaccine before delivery resulted in 10-fold higher cord anti-S antibody levels. Maternal antibody concentration appeared more important than delivery gestational age in determining cord anti-S antibody levels. The number of doses and timing considerations for COVID-19 vaccine in pregnancy should include individuals at risk for preterm delivery.

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Conflict of interest statement

Conflict of Interest Disclosures: Dr Kachikis reported working as an unpaid consultant for Pfizer and GlaxoSmithKline and as a coinvestigator for Merck and Pfizer outside the submitted work. Dr Greninger reported receiving grants from the Centers for Disease Control and Prevention during the conduct of the study and having central testing contracts with Abbott, Pfizer, Cepheid, Novavax, Janssen, and Hologic and receiving grants from Gilead outside the submitted work. Dr Englund reported receiving grants from University of Washington Support during the conduct of the study and grants from AstraZeneca, GlaxoSmithKline, Pfizer, and Merck, and personal fees from AbbVie, AstraZeneca, Meissa Vaccines, Moderna, Sanofi Pasteur, Pfizer, and Ark Biopharma outside the submitted work. No other disclosures were reported.

Figures

Figure 1.
Figure 1.. Maternal and Cord Anti-Spike (Anti-S) Protein Antibody Concentrations by Time From Last Vaccine Dose to Delivery
A, Scatterplot and linear fit line for the relationship between time between last dose and delivery and maternal anti-S IgG levels by number of doses prior to delivery, stratified by preterm status. B, Scatterplot and linear fit line for the relationship between time between last dose and delivery and cord anti-S IgG levels by number of doses prior to delivery, stratified by preterm status. The horizontal dashed lines are the upper testing limit of the assay.
Figure 2.
Figure 2.. Maternal and Cord Anti-Spike (Anti-S) Protein IgG Concentrations by Number of COVID-19 Doses Received Before Delivery
The horizontal lines in the boxes are the medians; upper and lower ends of the boxes indicate the 25th and 75th percentiles. Whiskers indicate all data points within 1.5 IQR of the upper and lower quartiles. Dots indicate outliers. The horizontal dashed lines indicate the upper testing limit of the assay.
See this image and copyright information in PMC

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