PC1053: Correlation of Maternal and Cord Blood sars-cov-2 Immunoglobulin Levels in COVID-19 During Pregnancy

Background: COVID-19 caused by SARS-CoV-2 virus has led to a worldwide pandemic and continues to affect the global population. Pregnant women are at higher risk for COVID-19 infection. The extent of vertical transmission still remains unclear and only a few cases of probable vertical transmission with neonatal morbidity have been reported. Maternal antibodies can be detected in umbilical cord blood as early as the first trimester and are a reliable source of identification of maternal past and recent infections at the time of delivery. To date, data on maternal transfer of anti-SARS-CoV-2 antibodies are limited. Understanding the dynamics of maternal antibody responses to SARS-CoV-2 infection during pregnancy and subsequent transplacental antibody transfer can inform neonatal management as well as maternal vaccination strategies.

Methods: We hypothesize there is a correlation between umbilical cord blood and maternal blood SARS-CoV-2 antibody levels. In-utero vertical transmission of SARS-COV-2 is possible and can be identified by presence of cord blood IgM. The study was approved by Institutional IRB. Covid-19 positive pregnant women admitted to labor and delivery were enrolled using informed consent. Covid-19 negative pregnant women were consented as control. Maternal blood was obtained at the time of enrollment and cord blood collected at delivery. Relevant clinical data from mother-infant dyad were collected. Samples were analyzed using a coronavirus antigen microarray containing immunologically significant antigens from SARS-CoV-2 which can detect SARS-CoV-2 immunoglobulin levels.

Results: 40 mother-infant dyads have been enrolled into the study and so far, 28 paired samples have been analyzed using microarray. Maternal and neonatal characteristics were similar between Covid-19 positive and negative patients (Table 1). 18 of these 28 were Covid-19 PCR positive whereas 10 were Covid-19 PCR negative at delivery. Our microarray results showed reactive IgG in 14 of 18 positive mothers. Interestingly, 9 of 10 negative mothers also showed reactive IgG. 6 of these 10 negative mothers were vaccinated against Covid-19. 9 of 18 positive mothers showed reactive IgM whereas none of the negative mothers had IgM reactivity. Similarly, cord blood analysis revealed reactive IgG in 12 of 18 positive mothers and 8 of 10 negative mothers. No SARS-CoV-2 IgM was detected in any of the cord blood samples.

Conclusion: Our microarray results showed that SARS-CoV-2 immunoglobulin levels in cord blood correlated well with maternal antibody levels. Our study supported the efficient transfer of SARS-CoV-2 maternally derived antibodies that may provide neonatal protection from Covid-19 infection. Further data and statistical analysis are underway to confirm this association.