Compromised SARS-CoV-2-specific placental antibody transfer

Vertical Transmission of SARS-CoV-2 during Pregnancy: A Prospective Italian Cohort Study

OBJECTIVE

 The extent of vertical transmission (VT) of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) from mothers their fetuses or neonates is still uncertain. We aimed to determine the incidence of VT.

STUDY DESIGN

 In this prospective cohort study. All mother diagnosed with SARS-CoV-2 infection at the time of delivery or up to 1 week prior and their neonates, managed in a tertiary referral hospital for pregnancy complicated by coronavirus disease 2019 (COVID-19) in Rome, from April 2 to December 22, 2020, were included. Maternal infection was defined as nasopharyngeal swab test results positive for SARS-CoV-2 reverse transcription-polymerase chain reaction (RT-PCR). Biological samples were collected before, at, and after delivery to test positivity for SARS-CoV-2 RT-PCR and anti-SARS-CoV-2-specific antibodies.

RESULTS

 The cohort included 95 women and 96 neonates with documented SARS-CoV-2 test results. Four neonates (4.2%) tested positive. The incidence of VT, according to the guidance criteria for diagnosing perinatal SARS-CoV-2 infection, was 5.2%. Neonatal symptoms were due to prematurity or fetal distress: symptomatic infants had lower median (min-max) gestational age, 38.1 (29.3-40.6) versus 39.3 (33.9-41.9) weeks (p = 0.036), and 1-minute and 5-minute Apgar scores, 9 (3-9) versus 9 (7-10) (p = 0.036) and 10 (6-10) versus 10 (8-10) (p = 0.012), respectively, than asymptomatic infants and needed more frequent assistance in the delivery room (22.2 vs 2.5%; p = 0.008). Only six (7.1%) neonates had anti-SARS-CoV-2-specific antibodies, despite the ongoing maternal infection.

CONCLUSION

 The incidence of VT is low as is the detection of specific anti-SARS-CoV-2 antibodies in cord blood when infection is contracted late in pregnancy. This would suggest poor protection of infants against horizontal transmission of the virus.

KEY POINTS

· VT of SARS-CoV-2 from pregnant mothers to fetuses or neonates can be possible.. · In this prospective cohort study, the incidence of VT is found to be 5.2%.. · VT is low but exists..

Seroprevalence and placental transfer of SARS-CoV-2 antibodies in unvaccinated pregnant women

PURPOSE

Pregnant women are at risk of severe SARS-CoV-2 infection, potentially leading to obstetric and neonatal complications. Placental transfer of antibodies directed to SARS-CoV-2 may be protective against neonatal COVID-19, but this remains to be studied. We aimed to determine the seroprevalence of SARS-CoV-2 antibodies in a population of unvaccinated pregnant women and to determine the placental transfer of these antibodies.

METHODOLOGY

A total of 1197 unvaccinated women with mostly unknown pre-study SARS-CoV-2 infection status, were tested at delivery for SARS-CoV-2 spike protein IgG antibodies during the first year of the pandemic. Umbilical cord samples were collected and assessed for seropositivity if the mother was seropositive. Maternal characteristics, pregnancy and neonatal outcomes and data on SARS-CoV-2 infection were extracted from medical records.

RESULTS

Specific IgG were detected in 258 women (21.6%). A significant placental transfer to the newborn was observed in 81.3% of cases. The earlier in the 2nd and 3rd trimesters that the mother had contracted the disease and the more symptomatic she was, the greater the likelihood of transplacental transfer of IgG to her newborn.

CONCLUSION

Approximately one in five women had detectable anti-SARS-CoV-2 spike protein IgG antibodies at delivery during the first year of the pandemic, and these antibodies were significantly transferred to their fetuses. This research provides further evidence to better understand the dynamics of the placental transfer of SARS-CoV-2 IgG antibodies from mothers to their newborns, which is necessary to improve vaccination strategies.

Maternal-driven immune education in offspring

Maternal environmental exposures, particularly during gestation and lactation, significantly influence the immunological development and long-term immunity of offspring. Mammalian immune systems develop through crucial inputs from the environment, beginning in utero and continuing after birth. These critical developmental windows are essential for proper immune system development and, once closed, may not be reopened. This review focuses on the mechanisms by which maternal exposures, particularly to pathogens, diet, and microbiota, impact offspring immunity. Mechanisms driving maternal-offspring immune crosstalk include transfer of maternal antibodies, changes in the maternal microbiome and microbiota-derived metabolites, and transfer of immune cells and cytokines via the placenta and breastfeeding. We further discuss the role of transient maternal infections, which are common during pregnancy, in providing tissue-specific immune education to offspring. We propose a "maternal-driven immune education" hypothesis, which suggests that offspring can use maternal encounters that occur during a critical developmental window to develop optimal immune fitness against infection and inflammation.

SARS-CoV-2 infection by trimester of pregnancy and adverse perinatal outcomes: a Mexican retrospective cohort study

OBJECTIVE

Conflicting evidence for the association between COVID-19 and adverse perinatal outcomes exists. This study examined the associations between maternal COVID-19 during pregnancy and adverse perinatal outcomes including preterm birth (PTB), low birth weight (LBW), small-for-gestational age (SGA), large-for-gestational age (LGA) and fetal death; as well as whether the associations differ by trimester of infection.

DESIGN AND SETTING

The study used a retrospective Mexican birth cohort from the Instituto Mexicano del Seguro Social (IMSS), Mexico, between January 2020 and November 2021.

PARTICIPANTS

We used the social security administrative dataset from IMSS that had COVID-19 information and linked it with the IMSS routine hospitalisation dataset, to identify deliveries in the study period with a test for SARS-CoV-2 during pregnancy.

OUTCOME MEASURES

PTB, LBW, SGA, LGA and fetal death. We used targeted maximum likelihood estimators, to quantify associations (risk ratio, RR) and CIs. We fit models for the overall COVID-19 sample, and separately for those with mild or severe disease, and by trimester of infection. Additionally, we investigated potential bias induced by missing non-tested pregnancies.

RESULTS

The overall sample comprised 17 340 singleton pregnancies, of which 30% tested positive. We found that those with mild COVID-19 had an RR of 0.89 (95% CI 0.80 to 0.99) for PTB and those with severe COVID-19 had an RR of 1.53 (95% CI 1.07 to 2.19) for LGA. COVID-19 in the first trimester was associated with fetal death, RR=2.36 (95% CI 1.04, 5.36). Results also demonstrate that missing non-tested pregnancies might induce bias in the associations.

CONCLUSIONS

In the overall sample, there was no evidence of an association between COVID-19 and adverse perinatal outcomes. However, the findings suggest that severe COVID-19 may increase the risk of some perinatal outcomes, with the first trimester potentially being a high-risk period.

Placental transfer dynamics and durability of maternal COVID-19 vaccine-induced antibodies in infants

Completion of a COVID-19 vaccination series during pregnancy effectively reduces COVID-19 hospitalization among infants less than 6 months of age. The dynamics of transplacental transfer of maternal vaccine-induced antibodies, and their persistence in infants at 2, 6, 9, and 12 months, have implications for new vaccine development and optimal timing of vaccine administration in pregnancy. We evaluated anti-COVID antibody IgG subclass, Fc-receptor binding profile, and activity against wild-type Spike and RBD plus five variants of concern (VOCs) in 153 serum samples from 100 infants. Maternal IgG1 and IgG3 responses persisted in 2- and 6-month infants to a greater extent than the other IgG subclasses, with high persistence of antibodies binding placental neonatal Fc-receptor and FcγR3A. Lowest persistence was observed against the Omicron RBD-specific region. Maternal vaccine timing, placental Fc-receptor binding capabilities, antibody subclass, fetal sex, and VOC all impact the persistence of antibodies in infants through 12 months of age.

Diverging Maternal and Cord Antibody Functions From SARS-CoV-2 Infection and Vaccination in Pregnancy

Maternal immunity impacts the infant, but how is unclear. To understand the implications of the immune exposures of vaccination and infection in pregnancy for neonatal immunity, we evaluated antibody functions in paired peripheral maternal and cord blood. We compared those who in pregnancy received mRNA coronavirus disease 2019 (COVID-19) vaccine, were infected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), and the combination. We found that vaccination enriched a subset of neutralizing activities and Fc effector functions that was driven by IgG1 and was minimally impacted by antibody glycosylation in maternal blood. In paired cord blood, maternal vaccination also enhanced IgG1. However, Fc effector functions compared to neutralizing activities were preferentially transferred. Moreover, changes in IgG posttranslational glycosylation contributed more to cord than peripheral maternal blood antibody functional potency. These differences were enhanced with the combination of vaccination and infection as compared to either alone. Thus, Fc effector functions and antibody glycosylation highlight underexplored maternal opportunities to safeguard newborns.

Impact of Antenatal SARS-CoV-2 Exposure on SARS-CoV-2 Neutralization Potency

A pregnancy booster dose significantly reduces the risk and severity of COVID-19, and it is widely recommended. A prospective cohort study was conducted to compare the transplacental passage of maternal antibodies from vaccination or infection during three trimesters against both the vaccine-targeted Wuhan strain and the Omicron strain of SARS-CoV-2. Maternal-infant dyads from vaccinated mothers were collected between 6 June 2022 and 20 September 2022. We analyzed 38 maternal-infant dyads from mothers who had been infected with COVID-19 and 37 from mothers without any previous infection. Pregnant women who received their last COVID-19 vaccine dose in the third trimester exhibited the highest anti-spike protein antibody levels and neutralizing potency against both the Wuhan strain and Omicron BA.2 variant in their maternal and cord plasma. Both second- and third-trimester vaccination could lead to a higher level of neutralization against the Wuhan and Omicron strains. COVID-19 infection had a negative effect on the transplacental transfer ratio of SARS-CoV-2 antibodies. A booster dose during the second or third trimester is encouraged for the maximum transplacental transfer of humoral protection against COVID-19 for infants.

Passive antibody transfer from pregnant women to their fetus are maximized after SARS-CoV-2 vaccination irrespective of prior infection

Background

Pregnancy is associated with a higher risk of adverse symptoms and outcomes for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection for both mother and neonate. Antibodies can provide protection against SARS-CoV-2 infection and are induced in pregnant women after vaccination or infection. Passive transfer of these antibodies from mother to fetus in utero may provide protection to the neonate against infection. However, it is unclear whether the magnitude or quality and kinetics of maternally derived fetal antibodies differs in the context of maternal infection or vaccination.

Objective

We aimed to determine whether antibodies transferred from maternal to fetus differed in quality or quantity between infection- or vaccination-induced humoral immune responses.

Methods

We evaluated 93 paired maternal and neonatal umbilical cord blood plasma samples collected between October 2020 and February 2022 from a birth cohort of pregnant women from New Orleans, Louisiana, with histories of SARS-CoV-2 infection and/or vaccination. Plasma was profiled for the levels of spike-specific antibodies and induction of antiviral humoral immune functions, including neutralization and Fc-mediated innate immune effector functions. Responses were compared between 4 groups according to maternal infection and vaccination.

Results

We found that SARS-CoV-2 vaccination or infection during pregnancy increased the levels of antiviral antibodies compared to naive subjects. Vaccinated mothers and cord samples had the highest anti-spike antibody levels and antiviral function independent of the time of vaccination during pregnancy.

Conclusions

These results show that the most effective passive transfer of functional antibodies against SARS-CoV-2 in utero is achieved through vaccination, highlighting the importance of vaccination in pregnant women.

Placental Transfer Efficiency of Neutralizing Antibodies on SARS-CoV-2 Vaccination before and after Pregnancy in Mexican Women

The protection of the neonate against pathogens depends largely on the antibodies transferred placentally from the mother; for this reason, maternal vaccination against emerging viruses, such as SARS-CoV-2, is of vital importance. Knowing some of the immunogenic factors that could alter the placental transfer of antibodies could aid in understanding the immune response and neonatal protection after maternal vaccination. In this study, we analyzed the efficiency of the placental transfer of binding and neutralizing antibodies, as well as some factors that could alter the passive immune response, such as the trimester of gestation at the time of immunization, the number of doses received by the mother and the type of vaccine. Binding IgG antibodies were detected by ELISA, and the detection of neutralizing antibodies was carried out using flow cytometry. Our results show efficient transfer rates (>1), which are higher when maternal vaccination occurs during the third trimester of gestation. Antibodies are detectable in mothers and their neonates after 12 months of maternal immunization, suggesting than the vaccination against COVID-19 before and during pregnancy in the Mexican population induces a lasting neutralizing response in mothers and their newborns.

Assessing the Impact of COVID-19 Vaccination on Preterm Birth: A Systematic Review with Meta-Analysis

During the coronavirus diseases 2019 (COVID-19) pandemic, the safety and efficacy of vaccination during pregnancy, particularly regarding the risk of preterm birth, have been a subject of concern. This systematic review aims to evaluate the impact of COVID-19 vaccination on preterm birth risk and to inform clinical practice and public health policies. Following PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, a database search included PubMed, Embase, and Scopus, conducted up until October 2023. Inclusion criteria focused on studies that examined COVID-19 vaccination during pregnancy and its correlation with preterm birth, defined as a birth before 37 weeks of gestation. Six studies met these criteria, encompassing 35,612 patients. A quality assessment was performed using the Newcastle-Ottawa Scale and the Cochrane Collaboration's tool, with the risk of bias evaluated via a funnel plot analysis and an Egger's regression test. The studies demonstrated geographical diversity, mainly from Israel, Romania, and the United States, with a blend of prospective and retrospective designs. The patient cohort's mean age was 31.2 years, with common comorbidities such as gestational diabetes and obesity affecting 9.85% of the total population. The vaccination types varied across the studies, with BNT162b2 being the most used. The results indicated a low heterogeneity among the included studies, evidenced by a Cochran's Q statistic of 2.10 and an I2 statistic of 13%. The meta-analysis yielded a pooled odds ratio (OR) for a preterm birth risk post-vaccination of approximately 1.03 (95% CI: 0.82-1.30), suggesting no significant increase in preterm birth risk was associated with COVID-19 vaccination. Notable findings included a low preterm birth rate (as low as 0.6% and up to 6.1%) with minimal differences in neonatal outcomes, such as birth weight and APGAR (appearance, pulse, grimace, activity, and respiration) scores between vaccinated and unvaccinated groups. This study concludes that a COVID-19 vaccination during pregnancy does not significantly increase the risk of preterm birth. These findings are crucial for reassuring healthcare providers and pregnant women about the safety of COVID-19 vaccines and supporting their use in public health strategies during the pandemic.

SARS-CoV-2 neutralizing antibody titers in maternal blood, umbilical cord blood, and breast milk

OBJECTIVE

We quantified neutralizing SARS-CoV-2 antibody against spike protein (nAb) levels after vaccination and SARS-CoV-2 infection in maternal serum, cord blood, and breast milk and determined whether they correlate with levels of spike protein binding antibody.

STUDY DESIGN

Women (n = 100) were enrolled on admission for delivery. Previous SARS-CoV-2 infection was defined by anti-nucleocapsid antibodies. Levels of nAb and binding antibodies against spike receptor binding domain were measured in maternal blood, cord blood, and milk.

RESULTS

Maternal nAb levels were higher after vaccine and infection than vaccine alone but waned rapidly. Levels of nAb in cord blood and milk correlated with maternal levels and were higher in cord blood than maternal. Spike protein binding antibody levels correlated with nAb.

CONCLUSION

SARS-CoV-2 vaccination near delivery may boost antibody-mediated immunity in the peripartum period. Neutralizing antibodies are passed transplacentally and into milk. Spike protein binding antibody may be a feasible proxy for nAb.

A narrative review of COVID-19 vaccination in pregnancy and breastfeeding

The Coronavirus pandemic has affected millions of people due to the spread of the Severe acute respiratory syndrome Coronavirus-2 (SARS-CoV-2) virus. Pregnant individuals and infants are most vulnerable given the increased risk of developing severe complications from SARS-CoV-2 infection. Recently, COVID-19 vaccination is recommended for pregnant women and infants starting at 6 months of age to prevent disease contraction and minimize disease severity. We conducted a review of the literature on COVID-19 vaccination to discuss vaccine safety and efficacy, immunity after maternal vaccination, transplacental transfer and persistence of antibodies, and public health implications. Current evidence supports the safety and efficacy of vaccination during pregnancy. Maternal vaccination provides greater antibody persistence in infants compared to immunity from natural infection. Furthermore, vaccination has demonstrated an increased rate of passive antibody transfer through the placenta and breast milk. Public health interventions are important in achieving herd immunity and ultimately ending the pandemic. IMPACT: This article highlights the benefits of COVID-19 vaccination during pregnancy with a review of the data describing safety and efficacy, passive and active immunity after maternal immunization, trans-placental transfer and persistence of protective antibodies, and public health implications. With this information, healthcare providers can provide up-to-date knowledge to their pregnant patients to help them form an informed decision on vaccination and combat vaccine hesitancy.

Variable selection in linear regression models: Choosing the best subset is not always the best choice

We consider the question of variable selection in linear regressions, in the sense of identifying the correct direct predictors (those variables that have nonzero coefficients given all candidate predictors). Best subset selection (BSS) is often considered the "gold standard," with its use being restricted only by its NP-hard nature. Alternatives such as the least absolute shrinkage and selection operator (Lasso) or the Elastic net (Enet) have become methods of choice in high-dimensional settings. A recent proposal represents BSS as a mixed-integer optimization problem so that large problems have become computationally feasible. We present an extensive neutral comparison assessing the ability to select the correct direct predictors of BSS compared to forward stepwise selection (FSS), Lasso, and Enet. The simulation considers a range of settings that are challenging regarding dimensionality (number of observations and variables), signal-to-noise ratios, and correlations between predictors. As fair measure of performance, we primarily used the best possible F1-score for each method, and results were confirmed by alternative performance measures and practical criteria for choosing the tuning parameters and subset sizes. Surprisingly, it was only in settings where the signal-to-noise ratio was high and the variables were uncorrelated that BSS reliably outperformed the other methods, even in low-dimensional settings. Furthermore, FSS performed almost identically to BSS. Our results shed new light on the usual presumption of BSS being, in principle, the best choice for selecting the correct direct predictors. Especially for correlated variables, alternatives like Enet are faster and appear to perform better in practical settings.

Immunomodulation of Antibody Glycosylation through the Placental Transfer

Establishing an immune balance between the mother and fetus during gestation is crucial, with the placenta acting as the epicenter of immune tolerance. The placental transfer of antibodies, mainly immunoglobulin G (IgG), is critical in protecting the developing fetus from infections. This review looks at how immunomodulation of antibody glycosylation occurs during placental transfer and how it affects fetal health. The passage of maternal IgG antibodies through the placental layers, including the syncytiotrophoblast, stroma, and fetal endothelium, is discussed. The effect of IgG subclass, glycosylation, concentration, maternal infections, and antigen specificity on antibody transfer efficiency is investigated. FcRn-mediated IgG transport, influenced by pH-dependent binding, is essential for placental transfer. Additionally, this review delves into the impact of glycosylation patterns on antibody functionality, considering both protective and pathological effects. Factors affecting the transfer of protective antibodies, such as maternal vaccination, are discussed along with reducing harmful antibodies. This in-depth examination of placental antibody transfer and glycosylation provides insights into improving neonatal immunity and mitigating the effects of maternal autoimmune and alloimmune conditions.

Multimodal, broadly neutralizing antibodies against SARS-CoV-2 identified by high-throughput native pairing of BCRs from bulk B cells

TruAB Discovery is an approach that integrates cellular immunology, high-throughput immunosequencing, bioinformatics, and computational biology in order to discover naturally occurring human antibodies for prophylactic or therapeutic use. We adapted our previously described pairSEQ technology to pair B cell receptor heavy and light chains of SARS-CoV-2 spike protein-binding antibodies derived from enriched antigen-specific memory B cells and bulk antibody-secreting cells. We identified approximately 60,000 productive, in-frame, paired antibody sequences, from which 2,093 antibodies were selected for functional evaluation based on abundance, isotype and patterns of somatic hypermutation. The exceptionally diverse antibodies included RBD-binders with broad neutralizing activity against SARS-CoV-2 variants, and S2-binders with broad specificity against betacoronaviruses and the ability to block membrane fusion. A subset of these RBD- and S2-binding antibodies demonstrated robust protection against challenge in hamster and mouse models. This high-throughput approach can accelerate discovery of diverse, multifunctional antibodies against any target of interest.

Quantitative mechanistic model reveals key determinants of placental IgG transfer and informs prenatal immunization strategies

Transplacental antibody transfer is crucially important in shaping neonatal immunity. Recently, prenatal maternal immunization has been employed to boost pathogen-specific immunoglobulin G (IgG) transfer to the fetus. Multiple factors have been implicated in antibody transfer, but how these key regulators work together to elicit selective transfer is pertinent to engineering vaccines for mothers to optimally immunize their newborns. Here, we present the first quantitative mechanistic model to uncover the determinants of placental antibody transfer and inform personalized immunization approaches. We identified placental FcγRIIb expressed by endothelial cells as a limiting factor in receptor-mediated transfer, which plays a key role in promoting preferential transport of subclasses IgG1, IgG3, and IgG4, but not IgG2. Integrated computational modeling and in vitro experiments reveal that IgG subclass abundance, Fc receptor (FcR) binding affinity, and FcR abundance in syncytiotrophoblasts and endothelial cells contribute to inter-subclass competition and potentially inter- and intra-patient antibody transfer heterogeneity. We developed an in silico prenatal vaccine testbed by combining a computational model of maternal vaccination with this placental transfer model using the tetanus, diphtheria, and acellular pertussis (Tdap) vaccine as a case study. Model simulations unveiled precision prenatal immunization opportunities that account for a patient's anticipated gestational length, placental size, and FcR expression by modulating vaccine timing, dosage, and adjuvant. This computational approach provides new perspectives on the dynamics of maternal-fetal antibody transfer in humans and potential avenues to optimize prenatal vaccinations that promote neonatal immunity.

Investigating the impact of Sinopharm COVID-19 vaccination on antibody response in pregnant women and their newborns

This study aims to investigate the levels of receptor-binding domain (RBD), spike, and neutralizing antibodies in pregnant women who received the Sinopharm vaccine and their newborns. A cross-sectional study was conducted at a tertiary center, Mashhad, Iran. We included 88 pregnant women who had received at least two doses of the Sinopharm vaccine. Maternal and umbilical cord blood samples taken at delivery were analyzed for antibodies using ELISA tests. Antibody levels did not vary significantly between women with two or three vaccine doses. Only 1.1% of mothers had undetectable levels of RBD antibodies, but detectable antibodies were observed in all newborns. A significant linear correlation was found between the levels of neutralizing antibodies (r = 0.7, p < 0.001) and RBD antibodies (r = 0.833, p < 0.001) in mothers and their newborns, but not for Spike antibodies (r = 0.214, p = 0.045). In mothers, high titers of antispike and RBD antibodies were observed at the time of delivery. The high titers of RBD and antispike antibodies were found in cord blood, suggesting potential neonatal immunity. Detectable levels of antibodies were found in both groups, regardless of the timing of vaccination. The Sinopharm vaccine generates detectable levels of antibodies in pregnant women, which are efficiently transferred to their newborns. The number of vaccine doses (two or three) did not significantly impact the levels of detectable antibodies. This underscores Sinopharm's potential efficacy in protecting pregnant women and their infants from COVID-19.

Neurologic sequelae of COVID-19 are determined by immunologic imprinting from previous coronaviruses

Coronavirus disease 2019 (COVID-19), which is caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), remains a global public health emergency. Although SARS-CoV-2 is primarily a respiratory pathogen, extra-respiratory organs, including the CNS, can also be affected. Neurologic symptoms have been observed not only during acute SARS-CoV-2 infection, but also at distance from respiratory disease, also known as long-COVID or neurological post-acute sequelae of COVID-19 (neuroPASC). The pathogenesis of neuroPASC is not well understood, but hypotheses include SARS-CoV-2-induced immune dysfunctions, hormonal dysregulations and persistence of SARS-CoV-2 reservoirs. In this prospective cohort study, we used a high throughput systems serology approach to dissect the humoral response to SARS-CoV-2 (and other common coronaviruses: 229E, HKU1, NL63 and OC43) in the serum and CSF from 112 infected individuals who developed (n = 18) or did not develop (n = 94) neuroPASC. Unique SARS-CoV-2 humoral profiles were observed in the CSF of neuroPASC compared with serum responses. All antibody isotypes (IgG, IgM, IgA) and subclasses (IgA1-2, IgG1-4) were detected in serum, whereas CSF was characterized by focused IgG1 (and absence of IgM). These data argue in favour of compartmentalized brain-specific responses against SARS-CoV-2 through selective transfer of antibodies from the serum to the CSF across the blood-brain barrier, rather than intrathecal synthesis, where more diversity in antibody classes/subclasses would be expected. Compared to individuals who did not develop post-acute complications following infection, individuals with neuroPASC had similar demographic features (median age 65 versus 66.5 years, respectively, P = 0.55; females 33% versus 44%, P = 0.52) but exhibited attenuated systemic antibody responses against SARS-CoV-2, characterized by decreased capacity to activate antibody-dependent complement deposition (ADCD), NK cell activation (ADNKA) and to bind Fcγ receptors. However, surprisingly, neuroPASC individuals showed significantly expanded antibody responses to other common coronaviruses, including 229E, HKU1, NL63 and OC43. This biased humoral activation across coronaviruses was particularly enriched in neuroPASC individuals with poor outcome, suggesting an 'original antigenic sin' (or immunologic imprinting), where pre-existing immune responses against related viruses shape the response to the current infection, as a key prognostic marker of neuroPASC disease. Overall, these findings point to a pathogenic role for compromised anti-SARS-CoV-2 responses in the CSF, likely resulting in incomplete virus clearance from the brain and persistent neuroinflammation, in the development of post-acute neurologic complications of SARS-CoV-2 infection.

Maternal antibody transfer rate of vaccination against SARS-CoV-2 before or during early pregnancy and its protective effectiveness on offspring

This study focuses on maternal antibody transfer following vaccination against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) before or during early pregnancy and its potential protective effects on infants, providing scientific evidence for vaccination strategies. This prospective study tested the samples for SARS-CoV-2 IgG antibody titers and neutralizing capacity and tracked the infections after birth. Perform multivariate analysis of factors influencing antibody transfer rate, newborn antibody titers, and infant infection. Total 87.1% (122/140) women received coronavirus disease 2019 (COVID-19) vaccine before or during early pregnancy, and 28 of them had breakthrough infection. The maternal and neonatal IgG positive rates at delivery were 60.7% (85/140) and 60.8% (87/143), respectively. A positive correlation was found between neonatal and maternal IgG antibody titers. Compared with the median IgG antibody transfer rate of infected pregnant women, that of vaccinated but not infected pregnant women was higher (1.21 versus: 1.53 [two doses], 1.71 [three doses]). However, neonatal IgG antibodies were relatively low (174.91 versus: 0.99 [two doses], 8.18 [three doses]), and their neutralizing capacity was weak. The overall effectiveness of maternal vaccination in preventing infant infection was 27.0%, and three doses had higher effectiveness than two doses (64.3% vs. 19.6%). Multivariate analysises showed that in vaccination group women receiving three doses or in infection group women with longer interval between infection and delivery had a higher antibody transfer rate and neonatal IgG antibody titer. More than half of women vaccinated before or during early pregnancy can achieve effective antibody transfer to newborns. However, the neonatal IgG antibody titer is low and has a weak neutralizing capacity, providing limited protection to infants.

Clinical outcomes and antibody transfer in a cohort of infants with in utero or perinatal exposure to SARS-CoV-2 (Coronascope Study)

We aimed to describe the outcomes, focusing on the hearing and neurological development, of infants born to mothers with COVID-19 during pregnancy and to evaluate the persistence of maternal antibodies in the first months of life. An observational, prospective study at a tertiary hospital in Madrid (Spain) on infants born to mothers with COVID-19 during pregnancy between March and September 2020 was conducted. A follow-up visit at 1-3 months of age with a physical and neurological examination, cranial ultrasound (cUS), SARS-CoV-2 RT-PCR on nasopharyngeal swab, and SARS-CoV-2 serology were performed. Hearing was evaluated at birth through the automated auditory brainstem response and at six months of age through the auditory steady-state response. A neurodevelopmental examination using the Bayley-III scale was performed at 12 months of age. Of 95 infants studied, neurological examination was normal in all of them at the follow-up visit, as was the cUS in 81/85 (95%) infants, with only mild abnormalities in four of them. Serology was positive in 47/95 (50%) infants, which was not associated with symptoms or severity of maternal infection. No hearing loss was detected, and neurodevelopment was normal in 96% of the infants (median Z score: 0).

CONCLUSION

In this cohort, the majority of infants born to mothers with COVID-19 during pregnancy were healthy infants with a normal cUS, no hearing loss, and normal neurodevelopment in the first year of life. Only half of the infants had a positive serological result during the follow-up.

WHAT IS KNOWN

• Hearing loss and neurodevelopmental delay in infants born to mothers with COVID-19 during pregnancy has been suggested, although data is inconsistent. Maternal antibody transfer seems to be high, with a rapid decrease during the first weeks of life.

WHAT IS NEW

• Most infants born to mothers with COVID-19 during pregnancy had normal hearing screening, cranial ultrasound, and neurodevelopmental status at 12 months of life. Antibodies against SARS-CoV-2 were only detected in 50% of the infants at two months of life.

Antibody attributes, Fc receptor expression, gestation and maternal SARS-CoV-2 infection modulate HSV IgG placental transfer

Antibody-dependent cellular cytotoxicity (ADCC) is associated with protection against neonatal herpes. We hypothesized that placental transfer of ADCC-mediating herpes simplex virus (HSV) immunoglobulin G (IgG) is influenced by antigenic target, function, glycans, gestational age, and maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Maternal and cord blood were collected from HSV-seropositive (HSV+) mothers pre-COVID and HSV+/SARS-CoV-2+ mothers during the pandemic. Transfer of HSV neutralizing IgG was significantly lower in preterm versus term dyads (transfer ratio [TR] 0.84 vs. 2.44) whereas the TR of ADCC-mediating IgG was <1.0 in both term and preterm pre-COVID dyads. Anti-glycoprotein D IgG, which had only neutralizing activity, and anti-glycoprotein B (gB) IgG, which displayed neutralizing and ADCC activity, exhibited different relative affinities for the neonatal Fc receptor (FcRn) and expressed different glycans. The transfer of ADCC-mediating IgG increased significantly in term SARS-CoV-2+ dyads. This was associated with greater placental colocalization of FcRn with FcγRIIIa. These findings have implications for strategies to prevent neonatal herpes.

Balance between maternal antiviral response and placental transfer of protection in gestational SARS-CoV-2 infection

The intricate interplay between maternal immune response to SARS-CoV-2 and the transfer of protective factors to the fetus remains unclear. By analyzing mother-neonate dyads from second and third trimester SARS-CoV-2 infections, our study shows that neutralizing antibodies (NAbs) are infrequently detected in cord blood. We uncovered that this is due to impaired IgG-NAb placental transfer in symptomatic infection and to the predominance of maternal SARS-CoV-2 NAbs of the IgA and IgM isotypes, which are prevented from crossing the placenta. Crucially, the balance between maternal antiviral response and transplacental transfer of IgG-NAbs appears to hinge on IL-6 and IL-10 produced in response to SARS-CoV-2 infection. In addition, asymptomatic maternal infection was associated with expansion of anti-SARS-CoV-2 IgM and NK cell frequency. Our findings identify a protective role for IgA/IgM-NAbs in gestational SARS-CoV-2 infection and open the possibility that the maternal immune response to SARS-CoV-2 infection might benefit the neonate in 2 ways, first by skewing maternal immune response toward immediate viral clearance, and second by endowing the neonate with protective mechanisms to curtail horizontal viral transmission in the critical postnatal period, via the priming of IgA/IgM-NAbs to be transferred by the breast milk and via NK cell expansion in the neonate.

Factors Affecting COVID-19 Vaccine Acceptance among Pregnant Women: A Cross Sectional Study from Abha City, Saudi Arabia

Background: Pregnant women can get infected with COVID-19 with serious sequelae to them and their fetus. Concerns about COVID-19 vaccination safety to mothers and babies, and doubts about its effectiveness, have hindered vaccine acceptance throughout the COVID-19 crisis. The objective of the current investigation was to estimate COVID-19 acceptance rates among pregnant women in Abha city, Aseer region, Saudi Arabia, and determine its clinical and demographic correlates. Method: Descriptive questionnaire-based cross-sectional survey of a sample of pregnant women attending regular antenatal care services in Abha. We used backward stepwise multiple logistic regression analysis to evaluate the predictability of vaccine acceptance in terms of baseline clinical and demographic factors. Results: The survey included 572 pregnant women. The prevalence of acceptance of COVID-19 vaccine was high (93.7%; 95%CI: 91.7-95.7%). University graduates and women with a later gestational age were more likely to accept vaccination (OR = 6.120, p = 0.009), (t = 2.163, p = 0.036), respectively. Confidence in vaccine safety was associated with better acceptance (OR = 3.431, p = 0.001). Conclusions: The acceptance rate for vaccination among pregnant women in Abha, Saudi Arabia, is higher compared to international rate. However, our results indicate that confidence in vaccine safety was associated with better acceptance. Hence, vaccine safety was the overarching predictor for harboring positive attitudes towards it. Public health policies should capitalize on such positive attitudes and aim for total coverage of pregnant women with COVID-19 vaccination including booster dosages.

Serologic evolution and follow-up to IgG antibodies of infants born to mothers with gestational COVID

BACKGROUND

It is known that SARS-CoV-2 antibodies from pregnant women with SARS-CoV-2 infection during pregnancy cross the placenta but the duration and the protective effect of these antibodies in infants is scarce.

METHODS

This prospective study included mothers with SARS-COV-2 infection during pregnancy and their infants from April 2020 to March 2021. IgG antibodies to SARS-CoV-2 spike protein were performed on women and infants at birth and at two and six months during follow-up. Anthropometrical measures and physical and neurological examinations and a clinical history of symptoms and COVID-19 diagnosis were collected. Simple linear regression was performed to compare categorical and continuous variables. To compare the mother's and infant's antibody titers evolution, a mixed linear regression model was used. A predictive model of newborn antibody titers at birth has been established by means of simple stepwise linear regression.

RESULTS

51 mother-infant couples were included. 45 (90%) of the mothers and 44 (86.3%) of the newborns had a positive serology al birth. These antibodies were progressively decreasing and were positive in 34 (66.7%) and 7 (13.7%) of infants at 2 and 6 months, respectively. IgG titers of newborns at birth were related to mothers' titers, with a positive moderate correlation (Pearson's correlation coefficient: 0.82, p < 0,001). Fetal/maternal antibodies placental transference rate was 1.3 (IQR: 0.7-2.2). The maternal IgG titers at delivery and the type of maternal infection (acute, recent, or past infection) was significantly related with infants' antibody titers at birth. No other epidemiological or clinical factors were related to antibodies titers. Neurodevelopment, psychomotor development, and growth were normal in 94.2% of infants in the third follow-up visit. No infants had a COVID-19 diagnosis during the follow-up period.

CONCLUSIONS

Transplacental transfer of maternal antibodies is high in newborns from mothers with recent or past infection at delivery, but these antibodies decrease after the first months of life. Infant's IgG titers were related to maternal IgG titers at delivery. Further studies are needed to learn about the protective role of maternal antibodies in infants.

Transplacental transfer of anti-SARS-CoV-2 neutralizing antibodies in comparison to other pathogens total antibodies

BACKGROUNDS

Due to immaturity of their immune system, passive maternal immunization is essential for newborns during their first months of life. Therefore, in the current context of intense circulation of SARS-CoV-2, identifying factors influencing the transfer ratio (TR) of neutralizing antibodies against SARS-CoV-2 (NAb) appears important.

METHODS

Our study nested in the COVIPREG cohort (NCT04355234), included mothers who had a SARS-CoV-2 PCR positive during their pregnancy and their newborns. Maternal and neonatal NAb levels were measured with the automated iFlash system.

RESULTS

For the 173 mother-infant pairs included in our study, the median gestational age (GA) at delivery was 39.4 weeks of gestation (WG), and 29.7 WG at maternal SARS-CoV-2 infection. Using a multivariate logistic model, having a NAb TR above 1 was positively associated with a longer delay from maternal positive SARS-CoV-2 PCR to delivery (aOR 1.09, 95% CI: 1.03 - 1.17) and with a later GA at delivery (aOR = 1.58, 95% CI: 1.09 - 2.52). It was negatively associated with being a male newborn (aOR 0.21, 95% CI: 0.07 - 0.59). In 3rd trimester SARS-CoV-2 infected mothers, NAb TR was inferior to VZV, toxoplasmosis, CMV, measle and rubella's TR. However, in 1st or 2nd trimester infected mothers, only measle TR was different from NAb TR.

CONCLUSION

Male newborn of mothers infected by SARS-CoV-2 during their pregnancy appear to have less protection against SARS-CoV-2 in their first months of life than female newborns. Measle TR was superior to NAb TR even in case of 1st or 2nd trimester maternal SARS-CoV-2 infection. Future studies are needed to investigate possible differences in transmission of NAb following infection vs vaccination and its impact on TR.

Polyfunctional antibodies: a path towards precision vaccines for vulnerable populations

Vaccine efficacy determined within the controlled environment of a clinical trial is usually substantially greater than real-world vaccine effectiveness. Typically, this results from reduced protection of immunologically vulnerable populations, such as children, elderly individuals and people with chronic comorbidities. Consequently, these high-risk groups are frequently recommended tailored immunisation schedules to boost responses. In addition, diverse groups of healthy adults may also be variably protected by the same vaccine regimen. Current population-based vaccination strategies that consider basic clinical parameters offer a glimpse into what may be achievable if more nuanced aspects of the immune response are considered in vaccine design. To date, vaccine development has been largely empirical. However, next-generation approaches require more rational strategies. We foresee a generation of precision vaccines that consider the mechanistic basis of vaccine response variations associated with both immunogenetic and baseline health differences. Recent efforts have highlighted the importance of balanced and diverse extra-neutralising antibody functions for vaccine-induced protection. However, in immunologically vulnerable populations, significant modulation of polyfunctional antibody responses that mediate both neutralisation and effector functions has been observed. Here, we review the current understanding of key genetic and inflammatory modulators of antibody polyfunctionality that affect vaccination outcomes and consider how this knowledge may be harnessed to tailor vaccine design for improved public health.

Transplacental Transfer of SARS-CoV-2 Receptor-Binding Domain IgG Antibodies from Mothers to Neonates in a Cohort of Pakistani Unvaccinated Mothers

The presence of COVID-19 antibodies in the maternal circulation is assumed to be protective for newborns against SARS-CoV-2 infection. We investigated whether maternal COVID-19 antibodies crossed the transplacental barrier and whether there was any difference in the hematological parameters of neonates born to mothers who recovered from COVID-19 during pregnancy. The cross-sectional study was conducted at the Saidu Group of Teaching Hospitals, located in Swat, Khyber Pakhtunkhwa. After obtaining written informed consent, 115 healthy, unvaccinated mother-neonate dyads were included. A clinical history of COVID-19-like illness, laboratory-confirmed diagnosis, and contact history were obtained. Serum samples from mothers and neonates were tested for SARS-CoV-2 anti-receptor-binding domain (anti-RBD) IgG antibodies. Hematological parameters were assessed with complete blood counts (CBC) and peripheral blood smear examinations. The study population consisted of 115 mothers, with a mean age of 29.44 ± 5.75 years, and most women (68/115 (59.1%)) were between 26 and 35 years of age. Of these mothers, 88/115 (76.5 percent) tested positive for SARS-CoV-2 anti-RBD IgG antibodies, as did 83/115 (72.2 percent) neonatal cord blood samples. The mean levels of SARS-CoV-2 IgG antibodies in maternal and neonatal blood were 19.86 ± 13.82 (IU/mL) and 16.16 ± 12.90 (IU/mL), respectively, indicating that maternal antibodies efficiently crossed the transplacental barrier with an antibody transfer ratio of 0.83. The study found no significant difference in complete blood count (CBC) parameters between seropositive and seronegative mothers, nor between neonates born to seropositive and seronegative mothers.

The contributions of parental lactation on offspring development: It's not udder nonsense!

The Developmental Origins of Health and Disease (DOHaD) hypothesis describes how maternal stress exposures experienced during critical periods of perinatal life are linked to altered developmental trajectories in offspring. Perinatal stress also induces changes in lactogenesis, milk volume, maternal care, and the nutritive and non-nutritive components of milk, affecting short and long-term developmental outcomes in offspring. For instance, selective early life stressors shape the contents of milk, including macro/micronutrients, immune components, microbiota, enzymes, hormones, milk-derived extracellular vesicles, and milk microRNAs. In this review, we highlight the contributions of parental lactation to offspring development by examining changes in the composition of breast milk in response to three well-characterized maternal stressors: nutritive stress, immune stress, and psychological stress. We discuss recent findings in human, animal, and in vitro models, their clinical relevance, study limitations, and potential therapeutic significance to improving human health and infant survival. We also discuss the benefits of enrichment methods and support tools that can be used to improve milk quality and volume as well as related developmental outcomes in offspring. Lastly, we use evidence-based primary literature to convey that even though select maternal stressors may modulate lactation biology (by influencing milk composition) depending on the severity and length of exposure, exclusive and/or prolonged milk feeding may attenuate the negative in utero effects of early life stressors and promote healthy developmental trajectories. Overall, scientific evidence supports lactation to be protective against nutritive and immune stressors, but the benefits of lactation in response to psychological stressors need further investigation.

Maternal HIV infection drives altered placental Mtb-specific antibody transfer

Introduction

Placental transfer of maternal antibodies is essential for neonatal immunity over the first months of life. In the setting of maternal HIV infection, HIV-exposed uninfected (HEU) infants are at higher risk of developing severe infections, including active tuberculosis (TB). Given our emerging appreciation for the potential role of antibodies in the control of Mycobacterium tuberculosis (Mtb), the bacteria that causes TB, here we aimed to determine whether maternal HIV status altered the quality of Mtb-specific placental antibody transfer.

Methods

Antigen-specific antibody systems serology was performed to comprehensively characterize the Mtb-specific humoral immune response in maternal and umbilical cord blood from HIV infected and uninfected pregnant people in Uganda.

Results

Significant differences were noted in overall antibody profiles in HIV positive and negative maternal plasma, resulting in heterogeneous transfer of Mtb-specific antibodies. Altered antibody transfer in HIV infected dyads was associated with impaired binding to IgG Fc-receptors, which was directly linked to HIV viral loads and CD4 counts.

Conclusions

These results highlight the importance of maternal HIV status on antibody transfer, providing clues related to alterations in transferred maternal immunity that may render HEU infants more vulnerable to TB than their HIV-unexposed peers.

Diverging maternal and infant cord antibody functions from SARS-CoV-2 infection and vaccination in pregnancy

Immunization in pregnancy is a critical tool that can be leveraged to protect the infant with an immature immune system but how vaccine-induced antibodies transfer to the placenta and protect the maternal-fetal dyad remains unclear. Here, we compare matched maternal-infant cord blood from individuals who in pregnancy received mRNA COVID-19 vaccine, were infected by SARS-CoV-2, or had the combination of these two immune exposures. We find that some but not all antibody neutralizing activities and Fc effector functions are enriched with vaccination compared to infection. Preferential transport to the fetus of Fc functions and not neutralization is observed. Immunization compared to infection enriches IgG1-mediated antibody functions with changes in antibody post-translational sialylation and fucosylation that impact fetal more than maternal antibody functional potency. Thus, vaccine enhanced antibody functional magnitude, potency and breadth in the fetus are driven more by antibody glycosylation and Fc effector functions compared to maternal responses, highlighting prenatal opportunities to safeguard newborns as SARS-CoV-2 becomes endemic.

Inflammatory and Immune Responses during SARS-CoV-2 Infection in Vaccinated and Non-Vaccinated Pregnant Women and Their Newborns

BACKGROUND

Pregnant women are more susceptible to severe disease associated with SARS-CoV-2 infection. We performed a prospective study to analyze the inflammatory and immune profile after SARS-CoV-2 infection occurring in vaccinated or non-vaccinated pregnant women and their newborns.

METHODS

Twenty-five pregnant women with SARS-CoV-2 infection were enrolled, and sixteen cord blood samples were obtained at delivery.

RESULTS

We observed that IL-1β, TNF-α, Eotaxin, MIB-1β, VEGF, IL-15, IL-2, IL-5, IL-9, IL-10 and IL-1ra levels were significantly higher in vaccinated than non-vaccinated mothers. Furthermore, the newborns of the vaccinated mothers produced higher levels of IL-7, IL-5 and IL-12 compared to the newborns of non-vaccinated mothers. Anti-Spike (S) IgG levels were significantly higher in all vaccinated mothers and their newborns compared to the non-vaccinated group. We found that 87.5% of vaccinated women and 66.6% of non-vaccinated women mounted an S-specific T-cell response quantified by ELISpot assay. Moreover, 75.0% of vaccinated mothers and 38.4% of non-vaccinated mothers showed S-specific CD4⁺ T-cell proliferative response. The T-helper subset response was restricted to CD4⁺ T_h1 in both vaccinated and non-vaccinated women.

CONCLUSION

A higher level of cytokines, IgG antibodies and memory T cells was noted in the vaccinated women. Furthermore, the maternal IgG antibody trans-placental transfer occurred more frequently in vaccinated mothers and may protect the newborn.

Immune profiling of SARS-CoV-2 infection during pregnancy reveals NK cell and γδ T cell perturbations

Pregnancy poses a greater risk for severe COVID-19; however, underlying immunological changes associated with SARS-CoV-2 during pregnancy are poorly understood. We defined immune responses to SARS-CoV-2 in unvaccinated pregnant and nonpregnant women with acute and convalescent COVID-19, quantifying 217 immunological parameters. Humoral responses to SARS-CoV-2 were similar in pregnant and nonpregnant women, although our systems serology approach revealed distinct antibody and FcγR profiles between pregnant and nonpregnant women. Cellular analyses demonstrated marked differences in NK cell and unconventional T cell activation dynamics in pregnant women. Healthy pregnant women displayed preactivated NK cells and γδ T cells when compared with healthy nonpregnant women, which remained unchanged during acute and convalescent COVID-19. Conversely, nonpregnant women had prototypical activation of NK and γδ T cells. Activation of CD4+ and CD8+ T cells and T follicular helper cells was similar in SARS-CoV-2-infected pregnant and nonpregnant women, while antibody-secreting B cells were increased in pregnant women during acute COVID-19. Elevated levels of IL-8, IL-10, and IL-18 were found in pregnant women in their healthy state, and these cytokine levels remained elevated during acute and convalescent COVID-19. Collectively, we demonstrate perturbations in NK cell and γδ T cell activation in unvaccinated pregnant women with COVID-19, which may impact disease progression and severity during pregnancy.

Proteomic analysis of plasma to identify novel biomarkers for intra-amniotic infection and/or inflammation in preterm premature rupture of membranes

To identify potential plasma biomarkers associated with microbial invasion of the amniotic cavity (MIAC) and/or intraamniotic inflammation (IAI) in women with preterm premature rupture of membranes (PPROM). This retrospective cohort study included 182 singleton pregnant women with PPROM (23-33 weeks) who underwent amniocentesis. Plasma samples; all subjects were chosen from these participants and were analyzed using label-free liquid chromatography-tandem mass spectrometry for proteome profiling using a nested case-control study design (cases with MIAC/IAI vs. non-MIAC/IAI controls [n = 9 each]). Three identified target molecules for MIAC/IAI were further verified by ELISA in the study cohort (n = 182). Shotgun proteomic analysis revealed 17 differentially expressed proteins (P < 0.05) in the plasma of MIAC/IAI cases. In particular, the levels of FCGR3A and haptoglobin, but not LRP1, were found to be increased in the plasma of patients with MIAC, IAI, and both MIAC/IAI compared with those without these conditions. Moreover, these differences remained significant after adjusting for gestational age at sampling. The area under the curves of plasma FCGR3A and haptoglobin ranged within 0.59-0.65 with respect to each of the three outcome measures. Plasma FCGR3A and haptoglobin were identified as potential independent biomarkers for less-invasively detecting MIAC/IAI in women with PPROM.

Pregnancy-specific responses to COVID-19 revealed by high-throughput proteomics of human plasma

BACKGROUND

Pregnant women are at greater risk of adverse outcomes, including mortality, as well as obstetrical complications resulting from COVID-19. However, pregnancy-specific changes that underlie such worsened outcomes remain unclear.

METHODS

Plasma samples were collected from pregnant women and non-pregnant individuals (male and female) with (n = 72 pregnant, 52 non-pregnant) and without (n = 29 pregnant, 41 non-pregnant) COVID-19. COVID-19 patients were grouped as asymptomatic, mild, moderate, severe, or critically ill according to NIH classifications. Proteomic profiling of 7,288 analytes corresponding to 6,596 unique protein targets was performed using the SOMAmer platform.

RESULTS

Herein, we profile the plasma proteome of pregnant and non-pregnant COVID-19 patients and controls and show alterations that display a dose-response relationship with disease severity; yet, such proteomic perturbations are dampened during pregnancy. In both pregnant and non-pregnant state, the proteome response induced by COVID-19 shows enrichment of mediators implicated in cytokine storm, endothelial dysfunction, and angiogenesis. Shared and pregnancy-specific proteomic changes are identified: pregnant women display a tailored response that may protect the conceptus from heightened inflammation, while non-pregnant individuals display a stronger response to repel infection. Furthermore, the plasma proteome can accurately identify COVID-19 patients, even when asymptomatic or with mild symptoms.

CONCLUSION

This study represents the most comprehensive characterization of the plasma proteome of pregnant and non-pregnant COVID-19 patients. Our findings emphasize the distinct immune modulation between the non-pregnant and pregnant states, providing insight into the pathogenesis of COVID-19 as well as a potential explanation for the more severe outcomes observed in pregnant women.

Diminished antiviral innate immune gene expression in the placenta following a maternal SARS-CoV-2 infection

BACKGROUND

COVID-19 is caused by the SARS-CoV-2 virus and is associated with critical illness requiring hospitalization, maternal mortality, stillbirth, and preterm birth. SARS-CoV-2 has been shown to induce placental pathology. However, substantial gaps exist in our understanding of the pathophysiology of COVID-19 disease in pregnancy and the long-term impact of SARS-CoV-2 on the placenta and fetus. To what extent a SARS-CoV-2 infection of the placenta alters the placental antiviral innate immune response is not well understood. A dysregulated innate immune response in the setting of maternal COVID-19 disease may increase the risk of inflammatory tissue injury or placental compromise and may contribute to deleterious pregnancy outcomes.

OBJECTIVE

We sought to determine the impact of a maternal SARS-CoV-2 infection on placental immune response by evaluating gene expression of a panel of 6 antiviral innate immune mediators that act as biomarkers of the antiviral and interferon cytokine response. Our hypothesis was that a SARS-CoV-2 infection during pregnancy would result in an up-regulated placental antiviral innate immune response.

STUDY DESIGN

We performed a case-control study on placental tissues (chorionic villous tissues and chorioamniotic membrane) collected from pregnant patients with (N=140) and without (N=24) COVID-19 disease. We performed real-time quantitative polymerase chain reaction and immunohistochemistry, and the placental histopathology was evaluated. Clinical data were abstracted. Fisher exact test, Pearson correlations, and linear regression models were used to examine proportions and continuous data between patients with active (<10 days since diagnosis) vs recovered COVID-19 (>10 days since diagnosis) at the time of delivery. Secondary regression models adjusted for labor status as a covariate and evaluated potential correlation between placental innate immune gene expression and other variables.

RESULTS

SARS-CoV-2 viral RNA was detected in placental tissues from 5 women with COVID-19 and from no controls (0/24, 0%). Only 1 of 5 cases with detectable SARS-CoV-2 viral RNA in placental tissues was confirmed to express SARS-CoV-2 nucleocapsid and spike proteins in syncytiotrophoblast cells. We detected a considerably lower gene expression of 5 critical innate immune mediators (IFNB, IFIT1, MXA, IL6, IL1B) in the chorionic villi and chorioamniotic membranes from women with active or recovered COVID-19 than controls, which remained significant after adjustment for labor status. There were minimal correlations between placental gene expression and other studied variables including gestational age at diagnosis, time interval between COVID-19 diagnosis and delivery, prepregnancy body mass index, COVID-19 disease severity, or placental pathology.

CONCLUSION

A maternal SARS-CoV-2 infection was associated with an impaired placental innate immune response in chorionic villous tissues and chorioamniotic membranes that was not correlated with gestational age at COVID-19 diagnosis, time interval from COVID-19 diagnosis to delivery, maternal obesity, disease severity, or placental pathology.

Maternal, Infant, and Breast Milk Antibody Response Following COVID-19 Infection in Early Versus Late Gestation

BACKGROUND

Coronavirus disease 2019 [severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)] infection at varying time points during the pregnancy can influence antibody levels after delivery. We aimed to examine SARS-CoV-2 IgG, IgM and IgA receptor binding domain of the spike protein and nucleocapsid protein (N-protein) reactive antibody concentrations in maternal blood, infant blood and breastmilk at birth and 6 weeks after SARS-CoV-2 infection in early versus late gestation.

METHODS

Mothers with SARS-CoV-2 infection during pregnancy were enrolled between July 2020 and May 2021. Maternal blood, infant blood and breast milk samples were collected at delivery and 6 weeks postpartum. Samples were analyzed for SARS-CoV-2 spike and N-protein reactive IgG, IgM and IgA antibodies. Antibody concentrations were compared at the 2 time points and based on trimester of infection ("early" 1st/2nd vs. "late" 3rd).

RESULTS

Dyads from 20 early and 11 late trimester infections were analyzed. For the entire cohort, there were no significant differences in antibody levels at delivery versus 6 weeks with the exception of breast milk levels which declined over time. Early gestation infections were associated with higher levels of breastmilk IgA to spike protein ( P = 0.04). Infant IgG levels to spike protein were higher at 6 weeks after late infections ( P = 0.04). There were strong correlations between maternal and infant IgG levels at delivery ( P < 0.01), and between breastmilk and infant IgG levels.

CONCLUSIONS

SARS-CoV-2 infection in early versus late gestation leads to a persistent antibody response in maternal blood, infant blood and breast milk over the first 6 weeks after delivery.

Transplacental transfer of SARS-CoV-2 antibodies: a cohort study

The purpose of this study was to examine the transfer rate of SARS-CoV-2 IgG antibodies in pregnancy and newborns. Two Danish labor wards screened all women for SARS-CoV-2 by PCR upon arrival. Women (n = 99) with a SARS-CoV-2 PCR-positive nasopharyngeal (NP) swab or with a household member with a positive swab at labor or any time during pregnancy, or COVID-19 symptoms upon admission (November 2020 through August 2021), were included. Mother and infant were tested by NP swabs at delivery, and maternal and infant (umbilical cord) venous blood samples were collected. We obtained clinical information including previous PCR test results from the medical records. SARS-Cov-2 IgM and quantified IgG antibodies were measured by enzyme-linked immunosorbent assay and transfer ratios of IgG. We detected IgG antibodies in 73 women and 65 cord blood sera and found a strong correlation between SARS-CoV-2 IgG concentrations in maternal and umbilical cord sera (r = 0.9; p < 0.05). Transfer ratio was > 1.0 in 51 out of 73 (69%) infants and > 1.5 in 26 (35%). We found that transfer was proportional to time from a positive SARS-CoV-2 PCR NP swab to delivery (r = 0.5; p < 0.05). Transfer ratios of SARS-CoV-2 antibodies were associated with time from infection to delivery with transfer ratios of more than 1.0 in the majority of seropositive mother-infant dyads.

Humoral signatures of MOG-antibody-associated disease track with age and disease activity

Myelin oligodendrocyte glycoprotein (MOG)-antibody (Ab)-associated disease (MOGAD) is an inflammatory demyelinating disease of the CNS. Although MOG is encephalitogenic in different mammalian species, the mechanisms by which human MOG-specific Abs contribute to MOGAD are poorly understood. Here, we use a systems-level approach combined with high-dimensional characterization of Ab-associated immune features to deeply profile humoral immune responses in 123 patients with MOGAD. We show that age is a major determinant for MOG-antibody-related immune signatures. Unsupervised clustering additionally identifies two dominant immunological endophenotypes of MOGAD. The pro-inflammatory endophenotype characterized by increased binding affinities for activating Fcγ receptors (FcγRs), capacity to activate innate immune cells, and decreased frequencies of galactosylated and sialylated immunoglobulin G (IgG) glycovariants is associated with clinically active disease. Our data support the concept that FcγR-mediated effector functions control the pathogenicity of MOG-specific IgG and suggest that FcγR-targeting therapies should be explored for their therapeutic potential in MOGAD.

mSphere of Influence: Pertussis Vaccination and Antibodies in Mothers and Infants

Susana Portillo works in the field of mother-infant immunity with an emphasis on vaccination and prevention of respiratory diseases. In this mSphere of Influence, she reflects here on how two pertussis vaccine articles made an impact on her research. She discusses how much more remains to be understood about the role of maternal antibodies in preventing or reducing infant illnesses, their capacity to engage other immune components to deliver an efficient antimicrobial response, and their influence on the infant's own response to vaccination. She emphasizes the need for safe and effective interventions that strengthen maternal and infant immunity before and after birth.

The association of neonatal SARS-CoV-2 anti-spike protein receptor-binding domain antibodies at delivery with infant SARS-CoV-2 infection under the age of 6 months: a prospective cohort study

OBJECTIVES

The aim of this study was to assess the association between neonatal SARS-CoV-2 antibody level at delivery and infant SARS-CoV-2 infection under the age of 6 months and to identify predictive factors for neonatal antibody level at delivery.

METHODS

In a prospective observational study, conducted between September 2021 and mid-February 2022, cord blood sera were tested for SARS-CoV-2 anti-spike receptor-binding domain antibodies after maternal BNT162b2 vaccination or infection. Infants were followed up for 6 months for SARS-CoV-2 infection.

RESULTS

Sixty-seven mother-infant dyads were enrolled; nine of those did not meet the eligibility criteria. Of the 58 mother-infant dyads included, 6-month follow-up data were available for 57 mother-infant dyads. The mean ± standard deviation log SARS-CoV-2 anti-spike antibody level at delivery was lower among infants who were COVID-19 positive versus negative during follow-up (3.41 ± 0.74 AU/mL, n = 12; vs. 3.87 ± 0.84 AU/mL, n = 46; p 0.036); a log titre of ≥4.07 AU/mL (11 750) at delivery was associated with a significantly lower likelihood of infant infection (1/26 vs. 11/32 in infants with antibody level of <4.07 log AU/mL, OR = 0.076 [95% CI, 0.076, 0.64], p 0.018). A spline curve model showed a linear decrease in antibody levels when the last dose was administered at ≤30 weeks of gestation (50 days before delivery), after which the antibody levels increased (R² = 0.50). In multivariate analysis, more vaccine doses, prior maternal infection, and last administered dose at ≥31 weeks of gestation were associated with higher antibody levels at delivery.

DISCUSSION

Higher anti-spike antibodies at delivery were associated with decreased risk of COVID-19 at the age of <6 months; the antibody level decreased linearly when the last dose was administered at ≤30 weeks of gestation. Future research should assess the effectiveness of a second booster during pregnancy against infant infection.

Seroprevalence of SARS-CoV-2 antibodies in Italy in newborn dried blood spots

OBEJCTIVES

Serosurveys can be used to monitor COVID-19 seroprevalence and conduct surveillance. Dried blood spot (DBS), used increasingly as a valuable sample to assay severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) antibodies (Ab), has several advantages, particularly in infants, due to the limited amount of blood required and its utility in testing a large number of samples in a limited time-frame. We evaluated SARS-CoV-2 IgG Ab prevalence in newborn DBS in the Trentino region of Italy, during the time period January 2020 - December 2021.

METHODS

Anti-SARS-CoV-2 IgG levels were determined in DBS by means of Anti-SARS-CoV-2 QuantiVac IgG ELISA assay (Euroimmun, Lubeck, Germany).

RESULTS

Analyses included 2,400 DBS from newborns (54% M, 46% F), samples being collected 2-3 days after birth. The first DBS that tested positive for anti-SARS-CoV-2 IgG antibodies was found in March 2020 and, up to May 2020, only 4 positive results were detected overall. Starting from June 2020, the positivity thresholds increased according to the epidemiological waves of the COVID-19 pandemic in Italy, with a robust increment in the winters of 2020 and 2021. The percentage of positive DBS rose from 0 to 6% to 10-47%, in 2020 and 2021, respectively.

CONCLUSIONS

This study demonstrates DBS is a suitable tool for both epidemiological purposes and surveillance in the SARS-CoV-2 pandemic, particularly in newborns and pregnant women, saving blood waste and sparing patients any discomfort.

Maternal Antibody Response and Transplacental Transfer Following Severe Acute Respiratory Syndrome Coronavirus 2 Infection or Vaccination in Pregnancy

BACKGROUND

Pregnant persons are at increased risk of severe coronavirus disease 2019 (COVID-19) and adverse obstetric outcomes. Understanding maternal antibody response, duration, and transplacental transfer after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and COVID-19 vaccination is important to inform public health recommendations.

METHODS

This prospective observational cohort study included 351 pregnant people who had SARS-CoV-2 infection or COVID-19 vaccination during pregnancy. Immunoglobulin (Ig) G and IgM to SARS-CoV-2 S1 receptor binding domain were measured in maternal and cord blood. Antibody levels and transplacental transfer ratios were compared across (1) disease severity for those with SARS-CoV-2 infection and (2) infection versus vaccination.

RESULTS

There were 252 individuals with SARS-CoV-2 infection and 99 who received COVID-19 vaccination during pregnancy. Birthing people with more severe SARS-CoV-2 infection had higher maternal and cord blood IgG levels (P = .0001, P = .0001). Median IgG transfer ratio was 0.87-1.2. Maternal and cord blood IgG were higher after vaccination than infection (P = .001, P = .001). Transfer ratio was higher after 90 days in the vaccinated group (P < .001). Modeling showed higher amplitude and half-life of maternal IgG following vaccination (P < .0001). There were no significant differences by fetal sex.

CONCLUSIONS

COVID-19 vaccination in pregnancy leads to higher and longer lasting maternal IgG levels, higher cord blood IgG, and higher transfer ratio after 90 days compared with SARS-CoV-2 infection. Greater infection severity leads to higher maternal and cord blood antibodies. Maternal IgG decreases over time following both vaccination and infection, reinforcing the importance of vaccination, even after infection, and vaccine boosters for pregnant patients.

Longitudinal Evaluation of Antibody Persistence in Mother-Infant Dyads After Severe Acute Respiratory Syndrome Coronavirus 2 Infection in Pregnancy

BACKGROUND

There are limited data on how coronavirus disease 2019 (COVID-19) severity, timing of infection, and subsequent vaccination impact transplacental transfer and persistence of maternal and infant antibodies.

METHODS

In a longitudinal cohort of pregnant women with polymerase chain reaction-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, maternal/infant sera were collected at enrollment, delivery/birth, and 6 months. Anti-SARS-CoV-2 spike immunoglobulin (Ig)G, IgM, and IgA were measured by enzyme-linked immunosorbent assay.

RESULTS

Two-hundred fifty-six pregnant women and 135 infants were enrolled; 148 maternal and 122 neonatal specimens were collected at delivery/birth; 45 maternal and 48 infant specimens were collected at 6 months. Sixty-eight percent of women produced all anti-SARS-CoV-2 isotypes at delivery (IgG, IgM, IgA); 96% had at least 1 isotype. Symptomatic disease and vaccination before delivery were associated with higher maternal IgG at labor and delivery. Detectable IgG in infants dropped from 78% at birth to 52% at 6 months. In the multivariate analysis evaluating factors associated with detectable IgG in infants at delivery, significant predictors were 3rd trimester infection (odds ratio [OR] = 4.0), mild/moderate disease (OR = 4.8), severe/critical disease (OR = 6.3), and maternal vaccination before delivery (OR = 18.8). No factors were significant in the multivariate analysis at 6 months postpartum.

CONCLUSIONS

Vaccination in pregnancy post-COVID-19 recovery is a strategy for boosting antibodies in mother-infant dyads.

Examination of cord blood at birth in women with SARS-CoV-2 exposure and/or vaccination during pregnancy and relationship to fetal complete blood count, cortisol, ferritin, vitamin D, and CRP

Background

SARS-CoV-2 is known to manifest a robust innate immune response. However, little is known about inflammatory influences from maternal SARS-CoV-2 infection or maternal mRNA vaccination upon the fetus. In addition, it is unknown if Vitamin D deficiency influences fetal homeostasis or if an anti-inflammatory mechanism to the development of possible innate cytokines or acute phase reactants by the maternal/fetal dyad, in the form of cortisol elevations, occur. In addition, effects on Complete Blood Count (CBC) are not known.

Objective

To evaluate the neonatal acute phase reactants and anti-inflammatory responses after maternal SARS-CoV-2 disease or mRNA vaccination.

Methods

Samples and medical records reviews from mother/baby dyads (n = 97) were collected consecutively, and were categorized into 4 groups; no SARS-CoV-2 or vaccination exposure (Control), Vaccinated mothers, maternal SARS-CoV-2 disease positive/IgG titer positive fetal blood, and maternal SARS-CoV-2 positive/IgG titer negative fetal blood. SARS-CoV-2 IgG/IgM/IgA titers, CBC, CRP, ferritin, cortisol, and Vitamin D were obtained to examine the possible development of an innate immune response and possible anti-inflammatory response. Student's t-test, Wilcoxon rank-sum, and Chi-squared with Bonferroni corrections were used to compare groups. Multiple imputations were performed for missing data.

Results

Cortisol was higher in babies of both mothers who were vaccinated (p = 0.001) and SARS-CoV-2 positive/IgG positive (p = 0.009) as compared to the control group suggesting an attempt to maintain homeostasis in these groups. Measurements of ferritin, CRP, and vitamin D did not reach statistical significance. CBC showed no variation, except for the mean platelet volume (MPV), which was elevated in babies whose mothers were vaccinated (p = 0.003) and SARS-CoV-2 positive/IgG positive (p = 0.007) as compared to the control group.

Conclusion

Acute phase reactant elevations were not noted in our neonates. Vitamin D levels were unchanged from homeostatic levels. Cord blood at birth, showed Cortisol and MPV higher in vaccinated and SARS-CoV-2 IgG positive mother/baby dyads as compared to the Control group, indicating that possible anti-inflammatory response was generated. The implication of possible inflammatory events and subsequent cortisol and/or MPV elevation effects upon the fetus after SARS-CoV-2 disease or vaccination is unknown and merits further investigation.

A large series of molecular and serological specimens to evaluate mother-to-child SARS-CoV-2 transmission: a prospective study from the Italian Obstetric Surveillance System

OBJECTIVES

To assay the presence of the SARS-CoV-2 genome in vaginal, rectal, and placental swabs among pregnant women and in newborn nasopharyngeal swabs and to investigate the immunological response and maternal antibody transfer through the umbilical cord blood and milk of unvaccinated mothers.

METHODS

Vaginal, rectal, and placental specimens, maternal and neonatal serum, and milk were collected from a wide cohort of pregnant Italian women with confirmed SARS-CoV-2 infection admitted to the hospital between February 25, 2020 and June 30, 2021. Samples were tested in selected reference laboratories according to a shared interlaboratory protocol.

RESULTS

Among 1086 enrolled women, the SARS-CoV-2 positive rate detected in all specimens ranged from 0.7% to 8.4%. Respectively, 45.2% of maternal sera collected during pregnancy and 39.7% of those collected at birth tested positive for immunoglobulin G, whereas 50.5% tested positive among neonates. Nasopharyngeal swabs were positive in 0.8% of the newborns, and immunoglobulin G was detected in 3.0% of the milk samples. The highest immunological response was recorded within 30 days during pregnancy and within 60 days of birth and in the neonatal population.

CONCLUSION

Vertical transmission should be considered a rare event; although, a good maternal immunological response and antibodies transfer throughout the umbilical cord blood was detected.

The Essentials about Neonatal Severe Acute Respiratory Syndrome Coronavirus 2 Infection and Coronavirus Disease: A Narrative Review

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection can occur in neonates as the virus can be transmitted both horizontally (from the environment) and vertically (during the pregnancy or at the delivery). Compared to the adult outbreak, neonatal infections do not represent a public health problem. Nonetheless, severe and life-threatening cases may rarely occur and both obstetricians and neonatologists should have a good knowledge of perinatal SARS-CoV-2 infection and related consequences. A high suspicion index must be applied and ruling out neonatal SARS-CoV-2 infection must become a part of the routine clinical workout. Moreover, neonates may be affected by the multisystem inflammatory syndrome, due to a dysregulated host response in the absence of any SARS-CoV-2 infection. We performed a narrative review to summarize here the available literature describing the essentials that should be known by every neonatologist and obstetrician, starting from what has been discovered in 2020 and adding what has been learned in the following years. The paper describes the mechanisms of transmission, clinical features, diagnostic tools, and criteria, as well as possible treatment and prevention strategies. The goal is to provide the practical points to be remembered at the bedside while caring for a pregnant woman or a neonate with suspected or proven coronavirus disease 2019 or multisystem inflammatory syndrome. KEY POINTS: · SARS-CoV-2 neonatal infections occur both vertically (30%) and horizontally (70%).. · Approximately, half of patients do not have clinical manifestations; clinical and laboratory signs are similar to those of adults but usually milder.. · Remdesivir and steroids can be used as a treatment..

Six-Month Outcomes of Infants Born to People With SARS-CoV-2 in Pregnancy

OBJECTIVES

To assess the 6-month incidence of laboratory-confirmed severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, postnatal care, hospitalization, and mortality among infants born to people with laboratory-confirmed SARS-CoV-2 infection during pregnancy by timing of maternal infection.

METHODS

Using a cohort of liveborn infants from pregnancies with SARS-CoV-2 infections in the year 2020 from 10 United States jurisdictions in the Surveillance for Emerging Threats to Mother and Babies Network, we describe weighted estimates of infant outcomes from birth through 6 months of age from electronic health and laboratory records.

RESULTS

Of 6601 exposed infants with laboratory information through 6 months of age, 1.0% (95% confidence interval: 0.8-1.1) tested positive, 19.1% (17.5-20.6) tested negative, and 80.0% (78.4-81.6) were not known to be tested for SARS-CoV-2. Among those ≤14 days of age, SARS-CoV-2 infection occurred only with maternal infection ≤14 days before delivery. Of 3967 infants with medical record abstraction, breastmilk feeding initiation was lower when maternal infection occurred ≤14 days before delivery compared with >14 days (77.6% [72.5-82.6] versus 88.3% [84.7-92.0]). Six-month all-cause hospitalization was 4.1% (2.0-6.2). All-cause mortality was higher among infants born to people with infection ≤14 days (1.0% [0.4-1.6]) than >14 days (0.3% [0.1-0.5]) before delivery.

CONCLUSIONS

Results are reassuring, with low incidences of most health outcomes examined. Incidence of infant SARS-CoV-2, breastmilk feeding initiation, and all-cause mortality differed by timing of maternal infection. Strategies to prevent infections and support pregnant people with coronavirus disease 2019 may improve infant outcomes.

SARS-CoV-2 Vaccine Booster Elicits Robust Prolonged Maternal Antibody Responses and Passive Transfer Via The Placenta And Breastmilk

Background

Infection during pregnancy can result in adverse outcomes for both pregnant persons and offspring. Maternal vaccination is an effective mechanism to protect both mother and neonate into post-partum. However, our understanding of passive transfer of antibodies elicited by maternal SARS-CoV-2 mRNA vaccination during pregnancy remains incomplete.

Objective

We aimed to evaluate the antibody responses engendered by maternal SARS-CoV-2 vaccination following initial and booster doses in maternal circulation and breastmilk to better understand passive immunization of the newborn.

Study Design

We collected longitudinal blood samples from 121 pregnant women who received SARS-CoV-2 mRNA vaccines spanning from early gestation to delivery followed by collection of blood samples and breastmilk between delivery and 12 months post-partum. During the study, 70% of the participants also received a booster post-partum. Paired maternal plasma, breastmilk, umbilical cord plasma, and newborn plasma samples were tested via enzyme-linked immunosorbent assays (ELISA) to evaluate SARS-CoV-2 specific IgG antibody levels.

Results

Vaccine-elicited maternal antibodies were detected in both cord blood and newborn blood, albeit at lower levels than maternal circulation, demonstrating transplacental passive immunization. Booster vaccination significantly increased spike specific IgG antibody titers in maternal plasma and breastmilk. Finally, SARS-CoV-2 specific IgG antibodies in newborn blood correlated negatively with days post initial maternal vaccine dose.

Conclusion

Vaccine-induced maternal SARS-CoV-2 antibodies were passively transferred to the offspring in utero via the placenta and after birth via breastfeeding. Maternal booster vaccination, regardless of gestational age at maternal vaccination, significantly increased antibody levels in breastmilk and maternal plasma, indicating the importance of this additional dose to maximize passive protection against SARS-CoV-2 infection for neonates and infants until vaccination eligibility.

COVID-19 vaccinations in pregnancy: Save mother and baby from COVID-19 pandemic

OBJECTIVE

The current study investigated the immune response of maternal coronavirus disease 2019 (COVID-19) vaccination and vertical transmission of anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) and nucleocapsid (N) proteins.

STUDY DESIGN

This retrospective study included pregnant women in Bahrain Defense Force Hospital from March 2021 to September 2021 who were vaccinated with Sinopharm or Pfizer/BioNTech. Testing of anti-N and -S levels from paired samples of maternal and umbilical cord blood was performed at the time of delivery. The immune response to vaccination, association with maternal and fetal factors, and vertical transmission of antibodies were studied.

RESULTS

The current study included 79 pregnant women. The median gestational age for those vaccinated with Sinopharm was 28 weeks and those vaccinated with Pfizer was 31 weeks, with 100% of the vaccinated population generating antibodies and showing vertical transmission. The anti-N and -S titers and interval frequencies varied in both vaccinations. The anti-N and -S and transfer ratio statistically correlated with maternal age, gestational age at delivery, latency period, and birth weight of the neonates differently in both vaccines. In addition, the peak level of antibodies and transfer ratios varied.

CONCLUSION

Although variations are exhibited in both types of vaccination, the vaccinated pregnant population generated a significant level of anti-N and -S and showed vertical transmission.