Severe Acute Respiratory Syndrome Coronavirus 2 Infection Versus Vaccination in Pregnancy: Implications for Maternal and Infant Immunity

Antibodies in breast milk: Pro-bodies designed for healthy newborn development

This manuscript sheds light on the impact of maternal breast milk antibodies on infant health. Milk antibodies prepare and protect the newborn against environmental exposure, guide and regulate the offspring's immune system, and promote transgenerational adaptation of the immune system to its environment. While the transfer of IgG across the placenta ceases at birth, milk antibodies are continuously replenished by the maternal immune system. They reflect the mother's real-time adaptation to the environment to which the infant is exposed. They cover the infant's upper respiratory and digestive mucosa and are perfectly positioned to control responses to environmental antigens and might also reach their circulation. Maternal antibodies in breast milk play a key role in the immune defense of the developing child, with a major impact on infectious disease susceptibility in both HIC and LMIC. They also influence the development of another major health burden in children-allergies. Finally, emerging evidence shows that milk antibodies also actively shape immune development. Much of this is likely to be mediated by their effect on the seeding, composition and function of the microbiota, but not only. Further understanding of the bridge that maternal antibodies provide between the child and its environment should enable the best interventions to promote healthy development.

Factors Influencing Breast Milk Antibody Titers during the Coronavirus Disease 2019 Pandemic: An Observational Study

The COVID-19 pandemic has highlighted the role of breastfeeding in providing passive immunity to infants via specific anti-SARS-CoV-2 antibodies in breast milk. We aimed to quantify these antibodies across different lactation stages and identify influencing factors. This prospective study involved mother-child dyads from Innsbruck University Hospital, Austria, with a positive maternal SARS-CoV-2 test during pregnancy or peripartum between 2020 and 2023. We collected breast milk samples at various lactation stages and analyzed anti-Spike S1 receptor-binding domain (S1RBD) immunoglobulins (Ig). Maternal and neonatal data were obtained from interviews and medical records. This study included 140 mothers and 144 neonates. Anti-S1RBD-IgA (72.0%), -IgG (86.0%), and -IgM (41.7%) were highly present in colostrum and decreased as milk matured. Mothers with natural infection and vaccination exhibited higher anti-S1RBD-IgA and -IgG titers in all milk stages. Mothers with moderate to severe infections had higher concentrations of anti-S1RBD-IgA and -IgG in transitional milk and higher anti-S1RBD-IgA and -IgM in mature milk compared to those with mild or asymptomatic infections. Variations in antibody responses were also observed with preterm birth and across different virus waves. This study demonstrates the dynamic nature of breast milk Ig and underscores the importance of breastfeeding during a pandemic.

Covid-19 vaccination during pregnancy: A mixed-methods study of attitudes in a sample of Italian women and the role of health professionals' communication

OBJECTIVES

We examined Italian pregnant women's attitudes about the diphtheria, tetanus, and pertussis (DTP) vaccine, seasonal influenza, and Covid-19 vaccines, healthcare professionals' (HP) communication, reasons and potential predictors for non-adherence.

METHODS

From August 2021 to January 2022, we carried out a cross-sectional study in Italy using an online self-administered questionnaire addressed to women of age and pregnant, designed using LimeSurvey and disseminated through social media. Questions explored vaccination attitude/perceptions, satisfaction, and trust in HPs' information. Thematic analysis of free-text responses was performed using MaxQDA 2022. Statistical analyses were performed using STATA.

RESULTS

1594 responses were obtained. 52% of women hesitated to be vaccinated against Covid-19 while pregnant. Information received by HPs was deemed incomplete by 56% of participants, unclear by 52%, and untrustworthy by 46%; 49% felt unsupported in their decision-making process. This variable was one predictor of vaccine hesitancy together with concern about vaccine safety in the multivariate model. The analysis of open-ended questions revealed a pervasive feeling of dissatisfaction.

CONCLUSION

The perceived lack of adequate communication and support by HPs affected pregnant women's decision-making process on Covid-19 vaccination.

PRACTICE IMPLICATIONS

HPs need to understand and communicate the importance of vaccination during pregnancy, learning to better tailor their messages.

Increasing Vaccine Uptake during Pregnancy by Using Prenatal Education Classes: An Effective Tool for Health Communication and Promotion

Childbirth education classes represent an antenatal tool for supporting pregnant women and couples in increasing knowledge on pregnancy, delivery, breastfeeding, and newborn care. The aim of this study was to investigate the impact of an additional lesson during the prenatal course regarding the advantage of vaccination to mitigation of maternal anxiety. An observational study was designed that included participants in childbirth education classes and compared courses enhanced by the extra lesson on vaccination during pregnancy versus those who did not receive it. Assessment of the impact of prenatal educational on vaccination was measured by using validated questionnaires (State-Trait Anxiety Inventory, STAI; Perceived Stress Scale, PSS; World Health Organization- Five Well-Being Index, WHO-5). A total of 145 pregnant women participated to the investigation by answering to the online survey. Of them, 33 patients (22.8%) belonged to the course without a lesson on vaccine, while 112 (77.2%) participated to online prenatal education that included an additional meeting on the usefulness of getting vaccinated during pregnancy. No statistical differences were found between study groups in terms of demographics and perinatal outcomes. Participants in the enriched course reported lower basal anxiety levels than those without the vaccine lesson (STAI-State, normal score < 40, 30 vs. 19%, p-value 0.041; STAI-State, mild score 40-50, 78 vs. 67%, p-value 0.037). With reference to the prior two weeks, maternal wellbeing level was improved by the added class (score > 13 as measurement of wellbeing: 62% vs. 80%, p-value < 0.05). Moderate perceived stress assessed by PSS was found in those pregnant women without prenatal education on vaccination (64 vs. 50%, p-value 0.042). The introduction of a lesson regarding vaccination during pregnancy in the program of prenatal education courses improved maternal anxiety levels and wellbeing, in addition to reducing perceived stress.

Vertical transmission and maternal passive immunity post-SARS-CoV-2

Since 2020, the highly contagious nature and various transmission routes of SARS-CoV-2 have rendered the pandemic interminable. Vertical transmission (VT) through the placenta and breast milk, which is frequent for certain virus types, is thought to exist for SARS-CoV-2 and is hypothesized by many researchers. Conversely, antibodies are produced to counteract the effect of viruses. Since newborns' immunologic system cannot produce proper antibodies, maternal antibodies are usually transferred from mother to infant/fetus to meet the need. This theory leads to the hypothesis of transmission of antibodies through the placenta and breast milk following SARS-CoV-2 infection or vaccination. This paper further discusses these hypotheses, considering consequences of fetus/infant harm versus benefit.

Anti-SARS-CoV-2 Immunoglobulins in Human Milk after Coronavirus Disease or Vaccination-Time Frame and Duration of Detection in Human Milk and Factors That Affect Their Titers: A Systematic Review

Human milk (HM) of mothers infected with or vaccinated against SARS-CoV-2 contains specific immunoglobulins, which may protect their offspring against infection or severe disease. The time frame and duration after infection or vaccination, during which these immunoglobulins are detected in HM, as well as the major factors that influence their levels, have not been fully elucidated. This systematic review aimed to collect the existing literature and describe the immune response, specifically regarding the immunoglobulins in HM after COVID-19 disease or vaccination in non-immune women. We conducted a systematic search of PubMed and Scopus databases to identify studies published up until 19 March 2023. In total, 975 articles were screened, and out of which 75 were identified as being relevant and were finally included in this review. Infection by SARS-CoV-2 virus primarily induces an IgA immune response in HM, while vaccination predominantly elevates IgG levels. These immunoglobulins give HM a neutralizing capacity against SARS-CoV-2, highlighting the importance of breastfeeding during the pandemic. The mode of immune acquisition (infection or vaccination) and immunoglobulin levels in maternal serum are factors that seem to influence immunoglobulin levels in HM. Further studies are required to determine the impact of other factors, such as infection severity, lactation period, parity, maternal age and BMI on immunoglobulin level in HM.

Associations of COVID-19 vaccination during pregnancy with adverse neonatal and maternal outcomes: A systematic review and meta-analysis

Objectives

The low COVID-19 vaccine uptake rate among pregnant women is mainly due to safety concerns about COVID-19 vaccines due to limited safety evidence. Our goal was to evaluate the safety of COVID-19 vaccination during pregnancy with up-to-date evidence.

Methods

A comprehensive search of MEDLINE, EMBASE, the Cochrane Library, and clinicaltrials.gov was performed on April 5th, 2022, and updated on May 25th, 2022. Studies evaluating the association of COVID-19 vaccination during pregnancy with adverse maternal and neonatal outcomes were included. Two reviewers independently performed the risk of bias assessment and data extraction. Inverse variance random effect meta-analyses were performed to pool outcome data.

Results

Forty-three observational studies were included. COVID-19 vaccination [96,384 (73.9%) BNT162b2, 30,889 (23.7%) mRNA-1273, and 3,172 (2.4%) other types] during pregnancy [23,721 (18.3%) in the first trimester, 52,778 (40.5%) in the second trimester, and 53,886 (41.2%) in the third trimester].was associated with reduced risks of stillbirth or neonatal death (OR, 0.74; 95% CI, 0.60-0.92). Sensitivity analysis restricted to studies in participants without COVID-19 showed that the pooled effect was not robust. COVID-19 vaccination during pregnancy was not associated with congenital anomalies (OR, 0.83; 95% CI, 0.63-1.08), preterm birth (OR, 0.98; 95% CI, 0.90-1.06), NICU admission or hospitalization (OR, 0.94; 95% CI, 0.84-1.04), an Apgar score at 5 min <7 (OR, 0.93; 95% CI, 0.86-1.01), low birth weight (OR, 1.00; 95% CI, 0.88-1.14), miscarriage (OR, 0.99; 95% CI, 0.88-1.11), cesarean delivery (OR, 1.07; 95% CI, 0.96-1.19), or postpartum hemorrhage (OR, 0.91; 95% CI, 0.81-1.01).

Conclusions

COVID-19 vaccination during pregnancy was not associated with any of the adverse neonatal or maternal outcomes studied. Interpretation of study findings is limited by the types and timing of vaccination. The vaccinations in our study received during pregnancy were primarily mRNA vaccines administered in the second and third trimester. Future RCTs and meta-analysis are warranted to evaluate the efficacy and long-term effects of the COVID-19 vaccines.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42022322525, identifier: PROSPERO, CRD42022322525.

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.

Clinical characteristics of COVID-19 in hospitalized young infants and risk factors for disease severity

BACKGROUND

This study aimed to describe the clinical characteristics and severity of young infants hospitalized with COVID-19 and study the relationship between breastfeeding and maternal COVID-19 vaccination on the severity of COVID-19.

METHODS

A retrospective, observational study was performed among infants aged 6 months and below hospitalized for COVID-19 in a tertiary state hospital in Malaysia between February 1 and April 30, 2022. The primary outcome was "serious disease," defined as pneumonia requiring respiratory support or dehydration with warning signs. Multivariate logistic regression was used to determine independent predictors for serious disease.

RESULTS

A total of 102 infants were included in the study; 53.9% were males with a median age of 11 weeks (interquartile range: 5-20 weeks). Sixteen patients (15.7%) had pre-existing comorbidities, including preterm birth. Fever was the most common presenting symptom (82.4%), followed by cough (53.9%), and rhinorrhea (31.4%). Forty-one infants (40.2%) presented with serious disease, warranting either respiratory support or intravenous fluid therapy for dehydration. Recent maternal COVID-19 vaccination was associated with a reduced risk of serious disease on univariate analysis but was not significant after multivariate adjustment (adjusted odds ratio [aOR] 0.39; 95% CI: 0.14-1.11; p = 0.08). Exclusive breastfeeding was protective against serious COVID-19 in young infants, independent of other confounding factors (aOR 0.21, 95% CI: 0.06-0.71; p = 0.01).

CONCLUSION

COVID-19 is a serious disease with non-specific clinical manifestations in young infants. Exclusive breastfeeding could play an important protective role.

Skewed fate and hematopoiesis of CD34+ HSPCs in umbilical cord blood amid the COVID-19 pandemic

Umbilical cord blood (UCB) is an irreplaceable source for hematopoietic stem progenitor cells (HSPCs). However, the effects of SARS-CoV-2 infection and COVID-19 vaccination on UCB phenotype, specifically the HSPCs therein, are currently unknown. We thus evaluated any effects of SARS-CoV-2 infection and/or COVID-19 vaccination from the mother on the fate and functionalities of HSPCs in the UCB. The numbers and frequencies of HSPCs in the UCB decreased significantly in donors with previous SARS-CoV-2 infection and more so with COVID-19 vaccination via the induction of apoptosis, likely mediated by IFN-γ-dependent pathways. Two independent hematopoiesis assays, a colony forming unit assay and a mouse humanization assay, revealed skewed hematopoiesis of HSPCs obtained from donors delivered from mothers with SARS-CoV-2 infection history. These results indicate that SARS-CoV-2 infection and COVID-19 vaccination impair the functionalities and survivability of HSPCs in the UCB, which would make unprecedented concerns on the future of HSPC-based therapies.

Action is needed to tackle the clinical, psychological and socioeconomic impact of perinatal COVID-19

The COVID-19 pandemic has turned perinatal healthcare into a worldwide public health challenge. Although initial data did not demonstrate pregnancy as a more susceptible period to adverse outcomes of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection, an increasing number of reports now certify maternal illness as a high-risk condition for the development of maternal-fetal complications. Despite the rarity of SARS-CoV-2 vertical transmission, severe maternal illness might induce adverse perinatal and neonatal outcomes. Additionally, perinatal COVID-19 data may raise concerns about long-term harmful consequences to the offspring in the framework of non-communicable diseases. The World Health Organization, as well as scientific literature, consider the protection of the maternal-fetal dyad against COVID-19 as a critical issue and, therefore, strongly promote and encourage vaccination of pregnant and lactating women. Furthermore, the pandemic has triggered an unprecedented recession, leading to historic levels of unemployment and deprivation, while health, societal, economic and gender inequities particularly affecting low-income and middle-income countries, have increased. This mini-review provides an updated brief report on historical, clinical, psychological and socioeconomic aspects of the COVID-19 pandemic based on 10 lectures presented at the 9^th Maria-Delivoria-Papadopoulos Perinatal Symposium, held virtually on 19 March 2022.