key: cord-0905415-uw5uigah
authors: MITHAL, Leena B.; OTERO, Sebastian; SHANES, Elisheva D.; GOLDSTEIN, Jeffery A.; MILLER, Emily S.
title: Cord Blood Antibodies following Maternal COVID-19 Vaccination During Pregnancy
date: 2021-04-01
journal: Am J Obstet Gynecol
DOI: 10.1016/j.ajog.2021.03.035
sha: ac2a5ab4884867ede2d5fe43eb525037d626328e
doc_id: 905415
cord_uid: uw5uigah

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of ≥1 considered positive. Antibody transfer ratio was calculated as infant IgG divided by maternal IgG concentrations.

Descriptive statistics were calculated. Linear regressions were used to identify factors significantly associated with antibody transfer ratios as well as infant IgG values. This study was IRB approved prior to its initiation.

We collected matched maternal plasma and cord blood from 27 women that received a COVID-19 vaccine during pregnancy; they delivered 28 infants (1 twin). Maternal age was 33 ± 3 (mean ± SD) years; race/ethnicity was 75% non-Hispanic white, 11% Hispanic. Gestational age at first vaccine dose was 33 ± 2 weeks. Vaccine type was 18 (64%) Pfizer, 6(18%) Moderna, and 4 (14%) unknown. Twenty-two women (74%) received both vaccine doses prior to delivery with a mean latency of 6 ± 3 weeks.

About half of women (15/27) and no infants had positive IgM (>1) ( Figure 1A ). All but 1 woman (26/27) had positive SARS-CoV-2 IgG at time of delivery. Only 3 infants did not have positive IgG

(1 set of twins); these 2 women had received their first vaccine less than 3 weeks prior to delivery.

The average maternal to infant IgG transfer ratio was 1.0 ± 0.6 ( Figure 1B) , however an increased latency from vaccination until delivery (weeks) was associated with an increased transfer ratio (β=0.2, 95% CI 0.1-0.2) ( Figure 1C) . Correspondingly, having received the second J o u r n a l P r e -p r o o f vaccine dose prior to delivery was significantly associated with increased infant IgG (β=19.0, 95% CI 7.1-30.8). Similarly, latency from vaccination to delivery was associated with increased infant IgG (β=2.9, 95% CI 0.7-5.1).

Most pregnant women who received the COVID-19 mRNA vaccine in the 3 rd trimester had transplacental transfer of IgG to the infant. The observed mean IgG transfer ratio demonstrates about equal infant antibody level to maternal level. This is slightly lower than what has been reported in pertussis vaccination (1.19 to 1.36) 5 , but greater than transfer ratio following SARS-CoV-2 infection (0.72 ± 0.57) 4 . A novel finding is that the transfer ratio appears to increase with latency from vaccination. These data suggest, at least among women in their third trimester, that earlier vaccination may produce greater infant immunity, the immunobiology of which requires further study.

Notably, due to vaccine eligibility and timing, most women included herein were healthcare workers in their 3 rd trimester. Future research, including a more diverse cohort of women and women who received vaccination earlier in their pregnancy, is needed. Nevertheless, these results show promising evidence of passive immunity against SARS-CoV-2 in newborns after maternal receipt of COVID-19 mRNA vaccine. 

Vaccines for pertussis and influenza: recommendations for use in pregnancy

COVID-19 vaccine response in pregnant and lactating women: a cohort study

Compromised SARS-CoV-2-specific placental