Efficient maternofetal transplacental transfer of anti- SARS-CoV-2 spike antibodies after antenatal SARS-CoV-2 BNT162b2 mRNA vaccination

Abstract

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy and early infancy can result in severe disease. Evaluating the serologic response after maternal vaccination during pregnancy and subsequent transplacental antibody transfer has important implications for maternal care and vaccination strategies. Objective To assess maternal and neonatal SARS-CoV-2 antibody levels after antenatal mRNA vaccination. Design, Setting, and Participants This study took place at Hadassah Medical Center in Jerusalem, Israel in February 2021. Maternal and cord blood sera were collected for antibody measurement from mother/newborn dyads following antenatal vaccination. Exposure SARS-CoV-2 BNT162b2 mRNA vaccination. Main outcome and measures Spike protein (S) and receptor binding domain (RBD)- specific, IgG levels were evaluated in maternal and cord blood sera. Results The study cohort consisted of 20 parturients, with a median maternal age of 32 years and a median gestational age of 393/7 weeks at the time of delivery. The median time lapsed from the first and second doses of vaccine administration until delivery was 33 [IQR 30-37] and 11 [IQR 9-15] days, respectively. Of the 20 dyads, all women and infants were positive for anti S- and anti-RBD-specific IgG. Anti-S and anti-RBD-specific IgG levels in maternal sera were positively correlated to their respective concentrations in cord blood (Rs= 0.72; P<0.001 and Rs = 0.72; P <0.001, respectively). Anti-S and anti-RBD-specific IgG titers in cord blood were directly correlated with time lapsed since the administration of the first vaccine dose (Rs = 0.71; P =0.001 and Rs= 0.63; P=0.004, respectively). Conclusion and Relevance In this study, SARS-CoV-2 mRNA vaccine administered during pregnancy induced adequate maternal serologic response with subsequent efficient transplacental transfer. Our findings highlight that vaccination of pregnant women may provide maternal and neonatal protection from SARS-CoV-2 infection.

Both SARS-CoV-2 infection and vaccination in pregnancy elicited neutralizing antibodies in pregnant women and newborns

“…On the other hand, a recent study conducted in Israel [ 6 ] reported a lower transfer ratio of anti-Spike IgG (median transfer ratio: 0.44) than that observed in our cases. The median time lapse between second dose administration and delivery was 11 days in the Israel cohort, whereas our subjects received the second dose 33 and 42 days before delivery.…”

Safety of COVID-19 vaccines, their components or their platforms for pregnant women: A rapid review

“…Three recent studies about mRNA-LNP vaccines in pregnant women, published after this rapid review was finalized, reinforced these findings[74-76]. Shimabukuro el al, published preliminary results from the U.S. surveillance review of the safety of mRNA COVID-19 vaccines during pregnancy[75].…”

“…COVID-19 vaccination in pregnancy induced a robust maternal immune response, with transplacental antibody transfer detectable as early as 16 days after the first dose. Rottenstreich et al, 20 pregnant women who received two doses of SARS-CoV-2 BNT162b2 (Pfizer/BioNTech) mRNA vaccine and found similar antibody response[76]. No safety concern was reported in any of these studies.…”

Interactions Between Specific Immune Status of Pregnant Women and SARS-CoV-2 Infection

“…A preliminary finding of mRNA safety of COVID-19 vaccine in pregnant women showed that vaccination is safe in the third trimester of pregnancy ( Shimabukuro et al., 2021 ). In addition to vaccination protecting women against COVID-19 and its complications during pregnancy, emerging evidence has shown transplacental transfer of SARS-CoV-2 antibodies after maternal COVID-19 vaccination during the third trimester, which suggests that maternal vaccination might provide some level of protection to the neonate ( Gill and Jones, 2021 ; Gray et al., 2021 ; Rottenstreich et al., 2021 ). To date, there is still little information on the efficacy and safety of vaccinating pregnant women.…”