Maternal and neonatal immune response to SARS-CoV-2, IgG transplacental transfer and cytokine profile

Cord blood IgA/M reveals in utero response to SARS-CoV-2 with fluctuations in relation to circulating variants

It is estimated that in utero SARS-CoV-2 infection is rare. However, few studies have systematically assessed for IgA and IgM antibodies indicating potential in utero response to SARS-CoV-2 infection using multi-isotype serology, and no studies have assessed in utero infection markers in relation to circulating variants. Between October 21, 2021 and February 15, 2023, remnant cord blood samples (CBS) from neonates born at a single hospital in Los Angeles, were systematically tested for serological markers suggesting in utero infection. SARS-CoV-2 specific fetal IgA and/or IgM antibodies were detected in 28.7% (298/1038 CBS, 95% CI: 26.0, 31.6), higher than previous in utero infection estimates that used only PCR and/or IgM. Importantly, the probability of detecting markers of in utero infection varied by month (P-value = 0.0144). The prevalence of fetal IgA/IgM varied with the emergence of new variants, increasing during the BA.1 wave with a peak in February 2022 at 36% (18/50, 95% CI: 22.7-49.3) and again during the BA.4/5 wave, with a peak at 48.8% in September 2022 (39/80, 95% CI 37.8-59.7), suggesting variant-related fluctuations. These data suggest it may be useful to identify SARS-Cov-2 in utero exposure at birth so these newborns may be more closely followed for adverse clinical outcomes.

Prenatal Maternal COVID-19 and Offspring Risk for Morbidities Up to the Age of One Year

BACKGROUND

Prenatal maternal coronavirus disease 2019 (COVID-19) infection may worsen the clinical course of the disease and increase the risk for adverse obstetric and neonatal outcomes depending on the severity of the disease and timing of exposure. Data regarding the long-term impact on offspring exposed to prenatal maternal COVID-19 are still limited.

OBJECTIVE

To study the association between prenatal maternal COVID-19 infection and offspring risk for infectious diseases, respiratory complications, and developmental delay up to the age of 1 year.

STUDY DESIGN

A retrospective cohort study was conducted. The study included 19,050 women-offspring dyads who delivered at the Soroka University Medical Center between December 30, 2020, and July 30, 2022, of them, 2663 (14%) women were diagnosed with COVID-19 infection during pregnancy. Pregnancy, delivery and offspring complications were compared between women who were diagnosed with COVID-19 infection during pregnancy and women who were not. Multivariable logistic regression models were performed to examine the association between maternal prenatal COVID-19 infection selected offspring diagnoses, while adjusting for background characteristics, and among exposed offspring, to compare the incidence of offspring diagnoses based on trimester of maternal infection.

RESULTS

Offspring of mothers with prenatal COVID-19 infections were at higher risk for viral infections [adjusted odds ratio (OR) = 1.167; 95% CI = 1.028-1.325, P = 0.017], specifically among offspring exposed during the third trimester. The risk for viral infections was lower in cases where the mothers were diagnosed with COVID-19 during the second trimester. These offspring were specifically at increased risk for COVID-19; however, only if the mothers were infected during the third trimester. The risk for offspring COVID-19 was lower if the mothers were diagnosed earlier during pregnancy. No associations were observed with the risk for developmental delay (0.8% vs. 1.1%, OR = 0.724, 95% CI = 0.46-1.14, P = 0.161) or respiratory complications (3.3% vs. 4%, OR = 0.83, 95% CI = 0.662-1.041, P = 0.107).

CONCLUSIONS

Offspring exposed to maternal COVID-19 infection were at increased risk for viral and COVID-19 infections up to the age of 1 year old, specifically if the mothers were infected during late third trimester. Offspring exposed to maternal COVID-19 infection earlier during gestation were at lower risk for viral infections including COVID-19 in the first year of life.

Impact of Maternal Exposure to SARS-CoV-2 on Immunological Components of Breast Milk

COVID-19, caused by SARS-CoV-2, has become a global public health threat. Although no replication-competent virus has been found in breast milk samples, breastfeeding practices during the pandemic were impacted. It is well known that breast milk is adapted to meet the needs of infants, providing the appropriate amounts of nutrients and various bioactive compounds that contribute to the maturation of the immune system and antioxidant protection, safeguarding infants against diseases. While its composition is variable, breast milk contains immune cells, antibodies, and cytokines, which have anti-inflammatory, pro-inflammatory, antiviral, and antibacterial properties that strengthen infant immunity. Since COVID-19 vaccines have not yet been approved for infants under six months of age, newborns rely on the passive transfer of antibodies via the placenta and breast milk to protect them against severe SARS-CoV-2 infection. Several studies that analyzed breast milk samples in the context of COVID-19 have demonstrated that a strong antibody response is induced following maternal infection with SARS-CoV-2. Therefore, this review aims to provide a comprehensive overview of the impact of maternal exposure to SARS-CoV-2 through natural infection and/or vaccination on the immunological composition of breast milk based on the studies conducted on this topic.

Cytokine Levels in Mother-infant Pairs at Term and Preterm Delivery

BACKGROUND

Cell-mediated immunity (CMI), in addition to the humoral immune response, is crucial in clearing infections. Cytokines are important mediators of the immune system and play a role during pregnancy and childbirth. This study assesses circulating cytokine levels in peripartum maternal and cord blood samples at term and preterm delivery.

MATERIALS AND METHODS

Samples from 37 mother-infant pairs from a previously conducted maternal immunization study were used to quantify levels of 6 cytokines [interferon (IFN)-γ, interleukin (IL)-10, IL-17A, IL-1β, IL-6 and tumor necrosis factor-α] using the Meso Scale Discovery® ultrasensitive S-plex assay. The effect of various factors on measured cytokine levels was determined.

RESULTS

Weak to moderate correlations between maternal and cord blood cytokine levels were found. A trend for lower cytokine levels for preterm compared with term delivery was observed. The trend for lower cytokine levels was also seen for cesarean section compared with vaginal delivery and multiparous compared with primiparous women, but only in maternal serum samples. After correction for other variables, the effects of gestational age at delivery and parity were only significant for, respectively, IFN-γ and IL-6 in maternal serum.

CONCLUSIONS

The assessment of circulating cytokine levels in mother-infant pairs at term and preterm deliveries provides a unique insight into the presence of cytokines in maternal and cord blood and their interplay at delivery. It also highlights the complexity of the maternal-fetal immune relationship and underscores the need for further investigation into the origin of cytokines in newborns and the impact of vaccination in pregnancy on CMI at delivery.

Risk of neonatal SARS-CoV-2 infection: a retrospective cohort study based on infected mothers with gestational diabetes mellitus

Background

The COVID-19 pandemic has posed unprecedented challenges to global public health, especially for pregnant women and their offspring. However, little is known about the impact of maternal SARS-CoV-2 infection on neonatal outcomes, particularly in the context of coexisting gestational diabetes mellitus (GDM).

Methods

Hospitalized pregnant women with SARS-CoV-2 infection were retrospectively enrolled between November 2022 and January 2023, and matched with pregnant subjects free of SARS-CoV-2 infection based on their propensity scores. All women were tested for SARS-CoV-2 upon admission as part of routine procedures, then divided into groups of pregnant women with SARS-CoV-2 infection and GDM (SARS2+GDM), pregnant women with SARS-CoV-2 infection but without GDM (SARS2+noGDM), and pregnant women without SARS-CoV-2 infection or GDM (Normal group). A logistic regression model was used to study the risk of GDM, perinatal SARS-CoV-2 infection, and their interaction on neonatal SARS-CoV-2 infection.

Results

Of 378 pregnant women with SARS-CoV-2 infection, the neonatal infection rate was higher in the GDM group as compared to the SARS-CoV-2 infection only group, but both SARS-CoV-2 infection rates were lower than that of the normal control group. Logistic regression analysis identified an interaction between maternal SARS-CoV-2 infection and GDM on neonatal infection, where maternal SARS-CoV-2 infection (odds ratio [OR] = 0.31, 95%CI: 0.22-0.44) and vaccination for anti-SARS-CoV-2 (OR = 0.70, 95%CI: 0.50-0.98) were associated with lower odds of neonatal infection, while higher pre-pregnancy body mass index (BMI) (OR = 1.06, 95% CI: 1.02-1.10) and GDM (OR = 1.97, 95%CI: 1.21-3.21) were associated with higher odds of neonatal infection.

Conclusions

We demonstrate that the coexistence of GDM and perinatal SARS-CoV-2 infection was associated with an increased probability of neonatal SARS-CoV-2 infection.

Maternal-fetal cytokine profiles in acute SARS-CoV-2 "breakthrough" infection after COVID-19 vaccination

Objective

Vaccination is protective against severe COVID-19 disease, yet whether vaccination reduces COVID-19-associated inflammation in pregnancy has not been established. The objective of this study is to characterize maternal and cord cytokine profiles of acute SARS-CoV-2 "breakthrough" infection (BTI) after vaccination, compared with unvaccinated infection and uninfected controls.

Study design

66 pregnant individuals enrolled in the MGH COVID-19 biorepository (March 2020-April 2022) were included. Maternal sera were collected from 26 unvaccinated and 21 vaccinated individuals with acute SARS-CoV-2 infection. Cord sera were collected at delivery. Maternal and cord sera from 19 term dyads without current or prior SARS-CoV-2 infection were analyzed as controls. Cytokines were quantified using the Human Inflammation 20-Plex ProcartaPlex assay.

Results

There was a significantly higher incidence of severe/critical maternal illness in unvaccinated pregnant individuals with SARS-CoV-2 compared to vaccinated (10/26 (38%) vs. 0/21 (0%), p<0.01). Significantly higher maternal levels of TNFα and CD62P were observed in vaccinated individuals with SARS-CoV-2 BTI compared with unvaccinated individuals with infection (p<0.05). Network correlation analyses revealed a distinct maternal cytokine response to SARS-CoV-2 in vaccinated vs unvaccinated individuals. Neither unvaccinated nor vaccinated SARS-CoV-2 infection resulted in elevated cord cytokines compared to controls. Multivariate analyses demonstrate distinct maternal and cord cytokine profiles in the setting of maternal SARS-CoV-2 at delivery.

Conclusion

Vaccination was associated with higher maternal cytokine levels during acute SARS-CoV-2 infection compared to unvaccinated infection, which may reflect vaccine-mediated priming of the immune system. A fetal inflammatory response specific to maternal SARS-CoV-2 infection was not observed.

Regulators of placental antibody transfer through a modeling lens

Infants are vulnerable to infections owing to a limited ability to mount a humoral immune response and their tolerogenic immune phenotype, which has impeded the success of newborn vaccination. Transplacental transfer of IgG from mother to fetus provides crucial protection in the first weeks of life, and maternal immunization has recently been implemented as a public health strategy to protect newborns against serious infections. Despite their early success, current maternal vaccines do not provide comparable protection across pregnancies with varying gestational lengths and placental and maternal immune features, and they do not account for the dynamic interplay between the maternal immune response and placental transfer. Moreover, progress toward the rational design of maternal vaccines has been hindered by inadequacies of existing experimental models and safety challenges of investigating longitudinal dynamics of IgG transfer in pregnant humans. Alternatively, in silico mechanistic models are a logical framework to disentangle the processes regulating placental antibody transfer. This Review synthesizes current literature through a mechanistic modeling lens to identify placental and maternal regulators of antibody transfer, their clinical covariates, and knowledge gaps to guide future research. We also describe opportunities to use integrated modeling and experimental approaches toward the rational design of vaccines against existing and emerging neonatal pathogen threats.

COVID-19 and Its Potential Impact on Children Born to Mothers Infected During Pregnancy: A Comprehensive Review

Pregnancy is a vulnerable period of time during which pregnant people are prone to infections like COVID-19, which can increase risks for both the mother and fetus. These infections may lead to complications such as preterm birth, developmental delays, and congenital abnormalities. While COVID-19 poses additional risks like placental dysfunction and neonatal infections, studies on long-term effects remain limited. Ongoing research and monitoring are essential to understand and mitigate potential cognitive and developmental challenges in children born to mothers infected with COVID-19. This review aims to guide clinicians in managing these risks throughout childhood. Maternal COVID-19 infection during pregnancy can have significant implications for fetal development, even if the newborn is not infected at birth. The release of inflammatory cytokines may cross the placental barrier, potentially disrupting fetal brain development and increasing the risk of long-term cognitive and behavioral issues, such as ADHD or autism. Placental dysfunction, caused by inflammation or thrombosis, can lead to intrauterine growth restriction (IUGR), preterm birth, or hypoxia, affecting both neurological and respiratory health in newborns. Furthermore, a compromised fetal immune system can increase susceptibility to autoimmune conditions and infections. The early diagnosis and management of infections during pregnancy are crucial in mitigating risks to both the mother and fetus. Swift intervention can prevent complications like preterm birth and long-term developmental challenges, ensuring better health outcomes for both the mother and child. Long-term monitoring of children born to mothers infected with COVID-19 is necessary to understand the full extent of the virus's impact. This review evaluates the long-term systemic effects of maternal COVID-19 infection during pregnancy on fetuses, newborns, and children, focusing beyond vertical transmission. It highlights the broader impacts on fetal development, offering insights to help clinicians manage potential issues that may arise later in life.

SARS-CoV-2 infection vs. vaccination during pregnancy: the placenta leads the way

PURPOSE OF REVIEW

To understand the characteristics and determinants of transplacental antibody transfer against SARS-CoV-2 and to compare the differences between SARS-CoV-2 infection and vaccination.

RECENT FINDINGS

The need for information during the COVID-19 pandemic and the exclusion of pregnant women from randomized clinical trials have led to a vast amount of clinical data primarily based on observational studies with diverse design and sample analyses that yield variable results. This review aims to critically and comprehensively integrate the relevant knowledge related to transplacental transfer of antibodies against SARS-CoV-2, emphasizing the differences between infection and vaccination.

SUMMARY

Passive immunization is key to conferring protection to the infant during their first months of life. Understanding the mechanisms of transplacental antibody transfer during SARS-CoV-2 infection and vaccination, and their associated protection will allow optimizing the implementation of well tolerated and effective preventive strategies for both pregnant women and infants.

Transplacental Transmission of SARS-CoV-2: A Narrative Review

Background and Objectives: The study aims to explore the potential for transplacental transmission of SARS-CoV-2, focusing on its pathophysiology, placental defense mechanisms, and the clinical implications for maternal and neonatal health. Materials and Methods: A comprehensive review of the current literature was conducted, analyzing studies on SARS-CoV-2 infection in pregnancy, the expression of key viral receptors (ACE2 and TMPRSS2) in placental cells, and the immune responses involved in placental defense. The review also examined the clinical outcomes related to maternal and neonatal health, including adverse pregnancy outcomes and neonatal infection. Results: The expression of ACE2 and TMPRSS2 in the placenta supports the biological plausibility of SARS-CoV-2 transplacental transmission. Histopathological findings from the infected placentas reveal inflammation, vascular changes, and the evidence of viral particles in placental tissues. Clinical reports indicate an increased risk of preterm birth, intrauterine growth restriction, and neonatal infection in pregnancies affected by COVID-19. However, the frequency and mechanisms of vertical transmission remain variable across studies, highlighting the need for standardized research protocols. Conclusions: SARS-CoV-2 can potentially infect placental cells, leading to adverse pregnancy outcomes and neonatal infection. While evidence of transplacental transmission has been documented, the risk and mechanisms are not fully understood. Ongoing research is essential to clarify these aspects and inform obstetric care practices to improve maternal and neonatal outcomes during the COVID-19 pandemic.

Maternal immunity shapes biomarkers of germinal center development in HIV-exposed uninfected infants

Introduction

HIV-exposed uninfected (HEU) infants exhibit elevated pro-inflammatory biomarkers that persist after birth. However, comprehensive assessments of bioprofiles associated with immune regulation and development in pregnant women with HIV (PWH) and HEU infants has not been performed. Maternal immunity in PWH may be imprinted on their HEU newborns, altering immune bioprofiles during early immune development.

Methods

Cryopreserved paired plasma samples from 46 HEU infants and their mothers enrolled in PACTG 316, a clinical trial to prevent perinatal HIV-1 transmission were analyzed. PWH received antiretrovirals (ARV) and had either fully suppressed or unsuppressed viral replication. Maternal blood samples obtained during labor and infant samples at birth and 6 months were measured for 21 biomarkers associated with germinal centers (GC), macrophage activation, T-cell activation, interferon gamma (IFN-γ)-inducible chemokines, and immune regulatory cytokines using Mesoscale assays. Pregnant women without HIV (PWOH) and their HIV unexposed uninfected (HUU) newborns and non-pregnant women without HIV (NPWOH) served as reference groups. Linear regression analysis fitted for comparison among groups and adjusted for covariant(s) along with principal component analysis performed to assess differences among groups.

Results

Compared with NPWOH, PWOH displayed higher levels of GC, macrophage, and regulatory biomarkers. PWH compared to PWOH displayed elevated GC, T cell activation, and IFN-γ-inducible chemokines biomarkers at delivery. Similar to their mothers, HEU infants had elevated GC, macrophage, and IFN-γ-inducible chemokines, as well as elevated anti-inflammatory cytokines, IL-10 and IL-1RA. Across all mother/newborn dyads, multiple biomarkers positively correlated, providing further evidence that maternal inflammation imprints on newborn bioprofiles. By 6 months, many HEU biomarkers normalized to levels similar to HUU infants, but some GC and inflammatory biomarkers remained perturbed. Bioprofiles in PWH and HEU infants were similar regardless of the extent of maternal viral suppression by ARV.

Conclusions

GC immune pathways are perturbed in HEU newborns, but immune regulatory responses down regulate inflammation during early infancy, indicating a transient inflammatory effect. However, several GC biomarkers that may alter immune development remain perturbed.

Serological Outcome in the First Months of Life of Children Born to Mothers with SARS-CoV-2 Infection during Pregnancy

BACKGROUND

The objective of this study is to analyze the transplacental transmission of SARS-CoV-2 antibodies, their persistence in newborns, the factors that may influence this transmission, and the protection these antibodies confer over time.

METHODS

This prospective cohort was conducted in a tertiary pediatric hospital in the Barcelona Metropolitan Region, Spain. It included neonates born to mothers who had SARS-CoV-2 infection during pregnancy or delivery between August 2020 and January 2022. We followed the recruited children for at least six months, and blood tests were performed to determine the presence of SARS-CoV-2 antibodies.

RESULTS

A total of 101 children were recruited. Among the serologies performed on children under three months of age, 44/82 were positive (53.7%). Newborns whose mothers presented more severe disease exhibited higher seropositivity odds (coefficient 9.747; p = 0.002). There were increased preterm deliveries when maternal infection occurred closer to the time of delivery. No severe SARS-CoV-2 infections were detected in children during the follow-up.

CONCLUSIONS

Slightly more than half of the SARS-CoV-2 serologies performed in the first three months were positive. This appears to confer protection during early childhood. The severity of maternal infection is the most significant factor influencing the transmission of antibodies in children born to unvaccinated mothers.

Timing of maternal vaccination against COVID-19 for effective protection of neonates: cohort study

Introduction

Although the safety and effectiveness of COVID-19 vaccination during pregnancy have been proven, there is still little data explaining neonatal outcomes of maternal pre-pregnancy vaccination.

Methods

Here, we investigated the impact of vaccination and SARS-CoV-2 infection on maternal-neonate immune response in a cohort study involving 141 pregnant individuals, and defined the importance of maternal COVID-19 vaccination timing for its effectiveness.

Results and discussion

Our data indicate that vertically transferred maternal hybrid immunity provides significantly better antiviral protection for a neonate than either maternal post-infection or post-vaccination immunity alone. Higher neutralization potency among mothers immunized before pregnancy and their newborns highlights the promising role of pre-pregnancy vaccination in neonatal protection. A comparison of neutralizing antibody titers calculated for each dyad suggests that infection and pre-/during-pregnancy vaccination all support transplacental transfer, providing the offspring with strong passive immunity against SARS-CoV-2. Analysis of neutralizing antibody levels in maternal sera collected during pregnancy and later during delivery shows that immunization may exert a positive effect on maternal protection.

SARS-CoV-2 infection, inflammation and birth outcomes in a prospective NYC pregnancy cohort

Associations between antenatal SARS-CoV-2 infection and pregnancy outcomes have been conflicting and the role of the immune system is currently unclear. This prospective cohort study investigated the interaction of antenatal SARS-CoV-2 infection, changes in cytokine and HS-CRP levels, birthweight and gestational age at birth. 2352 pregnant participants from New York City (2020-2022) were included. Plasma levels of interleukin (IL)-1β, IL-6, IL-17A and high-sensitivity C-reactive protein (HS-CRP) were quantified in blood specimens obtained across pregnancy. Quantile and linear regression models were conducted to 1) assess the impact of antenatal SARS-CoV-2 infection, overall and by timing of detection of SARS-CoV-2 positivity (< 20 weeks versus ≥ 20 weeks), on birthweight and gestational age at delivery; 2) examine the relationship between SARS-CoV-2 infection and maternal immune changes during pregnancy. All models were adjusted for maternal demographic and obstetric factors and pandemic timing. Birthweight models were additionally adjusted for gestational age at delivery and fetal sex. Immune marker models were also adjusted for gestational age at specimen collection and multiplex assay batch. 371 (15.8%) participants were infected with SARS-CoV-2 during pregnancy, of which 98 (26.4%) were infected at < 20 weeks gestation. Neither SARS-CoV-2 infection in general nor in early or late pregnancy was associated with lower birthweight nor earlier gestational age at delivery. Further, we did not observe cytokine or HS-CRP changes in response to SARS-CoV-2 infection and thus found no evidence to support a potential association between immune dysregulation and the diversity in pregnancy outcomes following infection.

Efficient transplacental transfer of SARS-CoV-2 antibodies between naturally exposed mothers and infants in Accra, Ghana

We aimed to determine SARS-CoV-2 antibody seropositivity among pregnant women and the transplacental transfer efficiency of SARS-CoV-2-specific antibodies relative to malaria antibodies among SARS-CoV-2 seropositive mother-cord pairs. This cross-sectional study was conducted in Accra, Ghana, from March to May 2022. Antigen- specific IgG antibodies against SARS-CoV-2 (nucleoprotein and spike-receptor binding domain) and malarial antigens (circumsporozoite protein and merozoite surface protein 3) in maternal and cord plasma were measured by ELISA. Plasma from both vaccinated and unvaccinated pregnant women were tested for neutralizing antibodies using commercial kit. Of the unvaccinated pregnant women tested, 58.12% at antenatal clinics and 55.56% at the delivery wards were seropositive for both SARS-CoV-2 nucleoprotein and RBD antibodies. Anti-SARS-CoV-2 antibodies in cord samples correlated with maternal antibody levels (N antigen rs = 0.7155, p < 0.001; RBD rs = 0.8693, p < 0.001). Transplacental transfer of SARS-CoV-2 nucleoprotein antibodies was comparable to circumsporozoite protein antibodies (p = 0.9999) but both were higher than transfer rates of merozoite surface protein 3 antibodies (p < 0.001). SARS-CoV-2 IgG seropositivity among pregnant women in Accra is high with a boost of SARS-CoV-2 RBD-specific IgG in vaccinated women. Transplacental transfer of anti-SARS-CoV-2 and malarial antibodies was efficient, supporting vaccination of mothers as a strategy to protect infants against SARS-CoV-2.

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.

Prenatal Infection by Respiratory Viruses Is Associated with Immunoinflammatory Responses in the Fetus

Rationale: Respiratory viral infections can be transmitted from pregnant women to their offspring, but frequency, mechanisms, and postnatal outcomes remain unclear. Objectives: The aims of this prospective cohort study were to compare the frequencies of transplacental transmission of respiratory syncytial virus (RSV) and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), analyze the concentrations of inflammatory mediators in maternal and fetal blood, and assess clinical consequences. Methods: We recruited pregnant women who developed upper respiratory infections or tested positive for SARS-CoV-2. Maternal and cord blood samples were collected at delivery. Study questionnaires and electronic medical records were used to document demographic and medical information. Measurements and Main Results: From October 2020 to June 2022, droplet digital PCR was used to test blood mononuclear cells from 103 mother-baby dyads. Twice more newborns in our sample were vertically infected with RSV compared with SARS-CoV-2 (25.2% [26 of 103] vs. 11.9% [12 of 101]; P = 0.019). Multiplex ELISA measured significantly increased concentrations of several inflammatory cytokines and chemokines in maternal and cord blood from newborns, with evidence of viral exposure in utero compared with control dyads. Prenatal infection was associated with significantly lower birth weight and postnatal weight growth. Conclusions: Data suggest a higher frequency of vertical transmission for RSV than SARS-CoV-2. Intrauterine exposure is associated with fetal inflammation driven by soluble inflammatory mediators, with expression profiles dependent on the virus type and affecting the rate of viral transmission. Virus-induced inflammation may have pathological consequences already in the first days of life, as shown by its effects on birth weight and postnatal weight growth.

Seroepidemiology of SARS-CoV-2 in a cohort of pregnant women and their infants in Uganda and Malawi

BACKGROUND

Data on SARS-CoV-2 infection in pregnancy and infancy has accumulated throughout the course of the pandemic, though evidence regarding asymptomatic SARS-CoV-2 infection and adverse birth outcomes are scarce. Limited information is available from countries in sub-Saharan Africa (SSA). The pregnant woman and infant COVID in Africa study (PeriCOVID Africa) is a South-South-North partnership involving hospitals and health centres in five countries: Malawi, Uganda, Mozambique, The Gambia, and Kenya. The study leveraged data from three ongoing prospective cohort studies: Preparing for Group B Streptococcal Vaccines (GBS PREPARE), SARS-CoV-2 infection and COVID-19 in women and their infants in Kampala and Mukono (COMAC) and Pregnancy Care Integrating Translational Science Everywhere (PRECISE). In this paper we describe the seroepidemiology of SARS-CoV-2 infection in pregnant women enrolled in sites in Uganda and Malawi, and the impact of SARS-CoV-2 infection on pregnancy and infant outcomes.

OUTCOME

Seroprevalence of SARS-CoV-2 antibodies in maternal blood, reported as the proportion of seropositive women by study site and wave of COVID-19 within each country.

METHODS

The PeriCOVID study was a prospective mother-infant cohort study that recruited pregnant women at any gestation antenatally or on the day of delivery. Maternal and cord blood samples were tested for SARS-CoV-2 antibodies using Wantai and Euroimmune ELISA. In periCOVID Uganda and Malawi nose and throat swabs for SARS-Cov-2 RT-PCR were obtained.

RESULTS

In total, 1379 women were enrolled, giving birth to 1387 infants. Overall, 63% of pregnant women had a SARS-CoV-2 positive serology. Over subsequent waves (delta and omicron), in the absence of vaccination, seropositivity rose from 20% to over 80%. The placental transfer GMR was 1.7, indicating active placental transfer of anti-spike IgG. There was no association between SARS-CoV-2 antibody positivity and adverse pregnancy or infancy outcomes.

Putative neural mechanisms underlying release-mode-specific abnormalities in dopamine neural activity in a schizophrenia-like model: The distinct roles of glutamate and serotonin in the impaired regulation of dopamine neurons

Abnormalities in dopamine function might be related to psychiatric disorders such as schizophrenia. Even at the same concentration, dopamine exerts opposite effects on information processing in the prefrontal cortex depending on independent dopamine release modes known as tonic and phasic releases. This duality of dopamine prevents a blanket interpretation of the implications of dopamine abnormalities for diseases on the basis of absolute dopamine levels. Moreover, the mechanisms underlying the mode-specific dopamine abnormalities are not clearly understood. Here, I show that the two modes of dopamine release in the prefrontal cortex of a schizophrenia-like model are disrupted by different mechanisms. In the schizophrenia-like model established by perinatal exposure to inflammatory cytokine, epidermal growth factor, tonic release was enhanced and phasic release was decreased in the prefrontal cortex. I examined the activity of dopamine neurons in the ventral tegmental area (VTA), which sends dopamine projections to the prefrontal cortex, under anaesthesia. The activation of VTA dopamine neurons during excitatory stimulation (local application of glutamate or N-methyl-d-aspartic acid [NMDA]), which is associated with phasic activity, was blunt in this model. Dopaminergic neuronal activity in the resting state related to tonic release was increased by disinhibition of the dopamine neurons due to the impairment of 5HT2 (5HT2A) receptor-regulated GABAergic inputs. Moreover, chronic administration of risperidone ameliorated this disinhibition of dopaminergic neurons. These results provide an idea about the mechanism of dopamine disturbance in schizophrenia and may be informative in explaining the effects of atypical antipsychotics as distinct from those of typical drugs.

Analysis of the transplacental transmission of SARS CoV-2 virus and antibody transfer according to the gestational age at maternal infection

To quantify transplacental transmission of SARS-CoV-2 virus and antibody transfer in pregnant women and their newborns according to the gestational age at maternal infection. A prospective observational multicenter study including pregnant women with a positive RT-PCR or a positive serology for SARS-CoV-2 and compatible symptoms, from April to December 2020, in 11 French maternities. The study was designed to obtain a systematic collection of mother-infant dyad's samples at birth. SARS-CoV-2 viral load was measured by RT-PCR. IgG and IgM antibodies against the SARS-CoV-2 spike protein were measured by enzyme-linked immunosorbent assay. Antibody concentrations and transplacental transfer ratios were analyzed according to the gestational age at maternal infection. The primary outcome was the rate of SARS CoV-2 materno-fetal transmission at birth. The secondary outcome was the quantification of materno-fetal antibody transfer. Maternal and neonatal outcomes at birth were additionally assessed. Among 165 dyads enrolled, one congenital infection was confirmed {n = 1 (0.63%) IC95% [0.02%; 3.48%]}. The average placental IgG antibody transfer ratio was 1.27 (IC 95% [0.69-2.89]). The transfer ratio increased with increasing time between the onset of maternal infection and delivery (P Value = 0.0001). Maternal and neonatal outcomes were reassuring. We confirmed the very low rate of SARS-CoV-2 transplacental transmission (< 1%). Maternal antibody transfer to the fetus was more efficient when the infection occurred during the first and second trimester of pregnancy.

Management of neonates with maternal prenatal coronavirus infection and influencing factors

The coronavirus disease 2019 (COVID-19) in pregnancy causes adverse outcomes for both the mother and the fetus. Neonates are at risk of vertical transmission and in-utero infection. Additionally, intensive care unit (ICU) admission and impairment in the organ systems of the mother are associated with neonatal outcomes, including impaired intrauterine growth, prematurity, and neonatal ICU admission. The management of neonates born from infected mothers has changed over the progress of the pandemic. At the beginning of the pandemic, cesarean section, immediate separation of mother-infant dyads, isolation of neonates, and avoiding of skin-to-skin contact, breast milk, and breastfeeding were the main practices to reduce vertical and horizontal transmission risk in the era of insufficient knowledge. The effects of antenatal steroids and delayed cord clamping on COVID-19 were also not known. As the pandemic progressed, data showed that prenatal, delivery room, and postnatal care of neonates can be performed as pre-pandemic practices. Variants and vaccines that affect clinical course and outcomes have emerged during the pandemic. The severity of the disease and the timing of infection in pregnancy also influence maternal and neonatal outcomes. The knowledge and lessons from COVID-19 will be helpful for the next pandemic if it happens. IMPACT: Prenatal infection with COVID-19 is associated with adverse maternal and neonatal outcomes. Our review includes the management of neonates with prenatal COVID-19 infection exposure, maternal-fetal, delivery room, and postnatal care of neonates, clinical features, treatment of neonates, and influencing factors such as variants, vaccination, severity of maternal disease, and timing of infection during pregnancy. There is a growing body of data and evidence about the COVID-19 pandemic. The knowledge and lessons from the pandemic will be helpful for the next pandemic if it happens.

Neonatal outcomes of maternal prenatal coronavirus infection

The coronavirus disease 2019 (COVID-19) pandemic has led to significant changes in life and healthcare all over the world. Pregnant women and their newborns require extra attention due to the increased risk of adverse outcomes. Adverse pregnancy outcomes include intensive care unit (ICU) admission, pulmonary, cardiac, and renal impairment leading to mortality. Immaturity and variations of the neonatal immune system may be advantageous in responding to the virus. Neonates are at risk of vertical transmission and in-utero infection. Impaired intrauterine growth, prematurity, vertical transmission, and neonatal ICU admission are the most concerning issues. Data on maternal and neonatal outcomes should be interpreted cautiously due to study designs, patient characteristics, clinical variables, the effects of variants, and vaccination beyond the pandemic. Cesarean section, immediate separation of mother-infant dyads, isolation of neonates, and avoidance of breast milk were performed to reduce transmission risk at the beginning of the pandemic in the era of insufficient knowledge. Vertical transmission was found to be low with favorable short-term outcomes. Serious fetal and neonatal outcomes are not expected, according to growing evidence. Long-term effects may be associated with fetal programming. Knowledge and lessons from COVID-19 will be helpful for the next pandemic if it occurs. IMPACT: Prenatal infection with SARS-CoV-2 is associated with adverse maternal and neonatal outcomes. Our review includes the effects of COVID-19 on the fetus and neonates, transmission routes, placental effects, fetal and neonatal outcomes, and long-term effects on neonates. There is a growing body of data and evidence about the COVID-19 pandemic. Knowledge and lessons from the pandemic will be helpful for the next pandemic if it happens.

Is SARS-CoV-2 vertical transmission still a current problem? A case report on a diagnosed SARS-CoV-2 infection with a positive sample of urines

BACKGROUND AND AIM

Current data suggest little to no possibility of original COVID-19 transmission in pregnant women to the fetus during pregnancy or childbirth. Warning with Omicron new variants has decreased.

CASE REPORT

A clinical case of a SARS-CoV-2 virus transplacental infection of a newborn, born at the end of 2022, from a mother who tested positive for Sars-covid-2 and positive IgM SARS-CoV-2 anti-virus. The newborn tested positive for SARS-CoV-2 12 hours after birth, and was clinically symptomatic after three days, an increase in IgM antibodies was not found, although the virus was identified in the urine samples through molecular tests. The insufficient time to determine the presence of antibodies and the immune system's state of immaturity can explain the lack of IgM in the newborn's blood at 14 days after birth.

CONCLUSIONS

The Omicron SARS-CoV-2 keeps provoking infections among newborns, especially if the mother contracts it during the third trimester. The host response is most likely influenced by the newborn's peculiar state of immune immaturity. Just before birth, a positive nasal swab and the presence of a positive urine examination confirmed the diagnosis of intraplacental exposure. Research on the virus through molecular tests of urines can represent an additional technique when an aetiological framework of the infection is necessary and a distinction between congenital and post-natal forms.

Mild/asymptomatic COVID-19 in unvaccinated pregnant mothers impairs neonatal immune responses

Maternal SARS-CoV-2 infection triggers placental inflammation and alters cord blood immune cell composition. However, most studies focus on outcomes of severe maternal infection. Therefore, we analyzed cord blood and chorionic villi from newborns of unvaccinated mothers who experienced mild/asymptomatic SARS-CoV-2 infection during pregnancy. We investigated immune cell rewiring using flow cytometry, single-cell RNA sequencing, and functional readouts using ex vivo stimulation with TLR agonists and pathogens. Maternal infection was associated with increased frequency of memory T and B cells and nonclassical monocytes in cord blood. Ex vivo T and B cell responses to stimulation were attenuated, suggesting a tolerogenic state. Maladaptive responses were also observed in cord blood monocytes, where antiviral responses were dampened but responses to bacterial TLRs were increased. Maternal infection was also associated with expansion and activation of placental Hofbauer cells, secreting elevated levels of myeloid cell-recruiting chemokines. Moreover, we reported increased activation of maternally derived monocytes/macrophages in the fetal placenta that were transcriptionally primed for antiviral responses. Our data indicate that even in the absence of vertical transmission or symptoms in the neonate, mild/asymptomatic maternal COVID-19 altered the transcriptional and functional state in fetal immune cells in circulation and in the placenta.

Maternal SARS-CoV-2 Infection at Delivery Increases IL-6 Concentration in Umbilical Cord Blood

BACKGROUND

SARS-CoV-2 infection in pregnant women may induce inflammation within the amniotic cavity and/or an increase in proinflammatory cytokines in fetal circulation. The aim was to investigate levels of IL-6 in maternal blood, umbilical cord blood, and amniotic fluid in pregnant women infected with SARS-CoV-2 at delivery.

METHODS

A single-center prospective observational case-control study of pregnant women diagnosed with SARS-CoV-2 infection at delivery was conducted. A total of 48 infected and 42 healthy women had IL-6 concentrations measured in their blood, amniotic fluid, and umbilical cord blood.

RESULTS

The concentrations of IL-6 in maternal blood and amniotic fluid were similar in the study and control groups, while umbilical cord blood concentrations were significantly higher in SARS-CoV-2-positive women. The umbilical cord blood IL-6 concentration was related to composite neonatal morbidity.

CONCLUSIONS

Maternal SARS-CoV-2 infection in pregnant women at delivery increases umbilical cord blood IL-6 concentration. The correlation between maternal and umbilical blood concentrations indicates a possibility of passage of IL-6 through the placenta. Perinatal alterations resulting from maternal SARS-CoV-2 infection at delivery carry a risk of impacting the health of infants even in asymptomatic course of infection.

Mild/Asymptomatic Maternal SARS-CoV-2 Infection Leads to Immune Paralysis in Fetal Circulation and Immune Dysregulation in Fetal-Placental Tissues

Few studies have addressed the impact of maternal mild/asymptomatic SARS-CoV-2 infection on the developing neonatal immune system. In this study, we analyzed umbilical cord blood and placental chorionic villi from newborns of unvaccinated mothers with mild/asymptomatic SARSCoV-2 infection during pregnancy using flow cytometry, single-cell transcriptomics, and functional assays. Despite the lack of vertical transmission, levels of inflammatory mediators were altered in cord blood. Maternal infection was also associated with increased memory T, B cells, and non-classical monocytes as well as increased activation. However, ex vivo responses to stimulation were attenuated. Finally, within the placental villi, we report an expansion of fetal Hofbauer cells and infiltrating maternal macrophages and rewiring towards a heightened inflammatory state. In contrast to cord blood monocytes, placental myeloid cells were primed for heightened antiviral responses. Taken together, this study highlights dysregulated fetal immune cell responses in response to mild maternal SARS-CoV-2 infection during pregnancy.

Immune Response and Transplacental Antibody Transfer in Pregnant Women after COVID-19 Vaccination

COVID-19 infection is associated with increased risk of pregnancy complications, making vaccination during pregnancy critical for mother-neonate dyads. Few data, often with an unrepresentative sample size, are available on SARS-CoV-2 vaccine-induced humoral and cell-mediated response. Here, we evaluated anti-S antibody and interferon-gamma (IFN-γ) production elicited by SARS-CoV-2 immunization in maternal and neonatal plasma. Pregnant women (n = 230) were prospectively enrolled and classified as unvaccinated (n = 103) and vaccinated (n = 127); after serological screening for previous infections, assays were performed on 126 dyads, 15 mothers and 17 newborns. Positive anti-S antibodies were found in most of the vaccinated subjects, regardless of timespan between immunization and delivery (range: 7-391 days). A total of 89 of 92 vaccinated women showed a broad response to COVID-19 immunization and highly effective placental transfer, as attested by anti-S positive rates (maternal = 96.7%, cord = 96.6%). Most of our subjects had indeterminate results in an IGRA assay, preventing a conclusive evaluation of IFN-γ production. Indeed, pregnancy-related hormonal changes may influence T-cell response with an impact on IFN-γ production. Positive pregnancy and perinatal outcomes reinforce the evidence that the anti-SARS-CoV-2 immunization is effective and well-tolerated in pregnant women and also protective for the fetus/neonate, even though it was not possible to define the related IFN-γ production and role.