Evaluation of Transplacental Antibody Transfer in SARS-CoV-2-Immunized Pregnant Women

Abstract

Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection during pregnancy could result in adverse perinatal outcome. Clinical data on the assessment of the immune response in vaccinated pregnant women and subsequent transplacental antibody transfer are quite limited. Objective: To assess maternal and neonatal neutralizing antibody levels against both wildtype and Delta (B.1.617.2) variants after maternal mRNA vaccination. Study Design: This cohort study was conducted 29 pregnant women who were vaccinated at least one dose of Moderna (mRNA-1273) vaccine. Both neutralizing antibody (wildtype and Delta variant) and S1 receptor binding domain IgG antibody levels were evaluated in maternal and cord blood on the day of delivery. Results: Superiority of antibody level was significant in fully vaccinated women compared with the one-dose group (maternal sera, median, 97.46%; cord sera, median, 97.37% versus maternal sera, median, 4.01%; cord sera, median, 1.44%). No difference in antibody level was noted in relation to interval of second immunization to delivery in the two-dose group (95.99% in 0–2 weeks, 97.45% in 2–4 weeks, 97.48% in 4–8 weeks, 97.72% in 8–10 weeks). The most pronounced reduction was observed for the Delta variant. The wildtype neutralizing antibody level of full-vaccinated women was not influenced by the pertussis vaccination. Conclusion: The data underscore the importance of full vaccination in pregnancy and support the recommendation of COVID-19 immunization for pregnant women. The lower level of vaccine-induced neutralizing antibodies for the Delta variant indicates insufficient protection for mother and newborn and highlights the need for development of effective vaccine strategies.

Covid-19 vaccination in pregnancy

“…An increase in maternal SARS-CoV-2 IgG antibody response with a second dose in pregnancy was also documented by a study that found significantly higher maternal IgG concentrations, week by week, starting two weeks after the first vaccine dose, as well as between the first and second weeks after the second vaccine dose (P<0.005 and P=0.019, respectively) 47. Another study also found higher antibody concentrations during pregnancy after two doses compared with one dose of Moderna vaccine 52…”

“…Our review identified 20 studies evaluating the immunogenicity of covid-19 vaccines in pregnancy (table 2). 3536373839404142434445464748495051525354 Most studies evaluated immunogenicity of the Pfizer-BioNTech vaccine. A few studies did not clearly describe either the vaccine platform or the total number of participants; however, when described, this information is provided in table 2.…”

Evidence of Maternal Antibodies Elicited by COVID-19 Vaccination in Amniotic Fluid: Report of Two Cases in Italy

“…Maternal vaccination during pregnancy provides this passive immunity [ 5 , 8 , 12 ]. Several studies reported anti-SARS-CoV-2 vaccine-elicited antibodies in umbilical cord blood and breastmilk after maternal vaccination [ 13 , 14 , 15 ]. To our knowledge, this is the first description of maternal antibodies directly in the amniotic fluid elicited by the COVID-19 vaccine during gestation.…”

“…Passive immunity depends on multiple factors, including maternal specific antibody levels and immune response dynamics, as well as the timing of vaccination for the IgG transfer across the placenta during gestation [ 8 ]. Full maternal immunization during pregnancy has been shown to maximize transplacental antibody transfer, with adequate seroprotection in young infants [ 13 ]. Protective antibodies elicited by maternal COVID-19 vaccination in newborns’ cord blood persisted in infants for at least six months [ 14 , 15 ].…”

Transplacental Transfer of Maternal Antibody against SARS-CoV-2 and Its Influencing Factors: A Review

“…Vaccination is essential for protecting pregnant women and their offspring from SARS-CoV-2 infection. Studies have shown that vaccinated women have significantly reduced COVID-19 infection during pregnancy compared with unvaccinated women [ 56 ] and that vaccination provides partial protection for pregnant women and their offspring, even in the face of some variants [ 57 ]. However, additional data are needed to determine how much these antibodies can protect newborns.…”