Maternal Immunization Research Articles

Discrete role for maternal stress and gut microbes in shaping maternal and offspring immunity

Psychosocial stress is prevalent during pregnancy, and is associated with immune dysfunction, both for the mother and the child. The gut microbiome has been implicated as a potential mechanism by which stress during pregnancy can impact both maternal and offspring immune function; however, the complex interplay between the gut microbiome and the immune system is not well-understood. Here, we leverage a model of antimicrobial-mediated gut microbiome reduction, in combination with a well-established model of maternal restraint stress, to investigate the independent effects of and interaction between maternal stress and the gut microbiome in shaping maternal and offspring immunity. First, we confirmed that the antimicrobial treatment reduced maternal gut bacterial load and altered fecal alpha and beta diversity, with a reduction in commensal microbes and an increase in the relative abundance of rare taxa. Prenatal stress also disrupted the gut microbiome, according to measures of both alpha and beta diversity. Furthermore, prenatal stress and antimicrobials independently induced systemic and gastrointestinal immune suppression in the dam with a concomitant increase in circulating corticosterone. While stress increased neutrophils in the maternal circulation, lymphoid cells and monocytes were not impacted by either stress or antimicrobial treatment. Although the fetal immune compartment was largely spared, stress increased circulating neutrophils and CD8 T cells, and antibiotics increased neutrophils and reduced T cells in the adult offspring. Altogether, these data indicate similar, but discrete, roles for maternal stress and gut microbes in influencing maternal and offspring immune function.

Rotavirus Infection in Swine: Genotypic Diversity, Immune Responses, and Role of Gut Microbiome in Rotavirus Immunity.

Rotaviruses (RVs) are endemic in swine populations, and all swine herds certainly have a history of RV infection and circulation. Rotavirus A (RVA) and C (RVC) are the most common among all RV species reported in swine. RVA was considered most prevalent and pathogenic in swine; however, RVC has been emerging as a significant cause of enteritis in newborn piglets. RV eradication from swine herds is not practically achievable, hence producers’ mainly focus on minimizing the production impact of RV infections by reducing mortality and diarrhea. Since no intra-uterine passage of immunoglobulins occur in swine during gestation, newborn piglets are highly susceptible to RV infection at birth. Boosting lactogenic immunity in gilts by using vaccines and natural planned exposure (NPE) is currently the only way to prevent RV infections in piglets. RVs are highly diverse and multiple RV species have been reported from swine, which also contributes to the difficulties in preventing RV diarrhea in swine herds. Human RV-gut microbiome studies support a link between microbiome composition and oral RV immunogenicity. Such information is completely lacking for RVs in swine. It is not known how RV infection affects the functionality or structure of gut microbiome in swine. In this review, we provide a detailed overview of genotypic diversity of swine RVs, host-ranges, innate and adaptive immune responses to RVs, homotypic and heterotypic immunity to RVs, current methods used for RV management in swine herds, role of maternal immunity in piglet protection, and prospects of investigating swine gut microbiota in providing immunity against rotaviruses.

Molecular hydrogen has a positive impact on pregnancy maintenance through enhancement of mitochondrial function and immunomodulatory effects on T cells

AimsMolecular hydrogen (H2) has attracted growing interest because of its implications in various diseases. However, the molecular mechanisms underlying the remarkable effect of a small amount of H2 remain elusive. No knowledge has been available on the role of H2 in the etiology of pregnancy disorders or its direct influence on human immune cells. Since maternal immunity, T cells in particular, plays a critical role in pregnancy maintenance. We investigated the effects of H2 on T cells and its relation to preterm birth (PTB). Main methodsExhaled H2 concentrations in pregnant women were measured and correlated with cytokine concentrations in maternal and umbilical cord blood. H2 was added to T cells collected from healthy donors, and differentiation and proliferation were examined. Energy metabolism was also examined. H2 was administered to mice and cytokine expression was compared. Key findingsOur prospective observational study revealed that maternal production of H2 is significantly lower in pregnant women with PTB, suggesting its potential as a biomarker for predicting PTB. We found that H2 has clear associations with several maternal cytokines, and acts as an immunomodulator by exerting mitochondrial function in human T cells. Moreover, in vivo administration of H2 to pregnant mice regulated inflammatory responses and reduced PTB caused by T cell activation, which further supports the notion that H2 may contribute to prolonged gestation through its immunomodulatory effect. SignificanceMeasuring maternal H2-production could be a potential clinical tool in the management of PTB, and H2 may have positive impact on pregnancy maintenance.

Genome-Wide Scan Reveals Toll-Like Receptor Contraction Events in Oplegnathidae.

The striped knifejaw (Oplegnathus fasciatus) and spotted knifejaw (Oplegnathus punctatus) are prominent members of the Oplegnathidae family and are rocky reef-loving fishes with high ecological and economic value. However, the frequent occurrence of diseases in these fishes has severely restricted the development of their breeding industry. Toll-like receptors (TLRs) play an important role in resistance to pathogens as part of innate immunity. Genome-wide scans and cross-species comparative analysis revealed 10 TLRs in O. fasciatus (OfTLRs) and only 5 in O. punctatus (OpTLRs). In contrast to those of mammals and other fishes, the TLR family of Oplegnathidae underwent significant contraction events, especially in O. punctatus (only TLR1, TLR2, TLR14, TLR5, and TLR21 were retained). A phylogenetic tree divided the 10 OfTLRs into 5 subfamilies: TLR1, TLR3, TLR5, TLR7, and TLR11. The five OpTLR genes were divided into three different subfamilies: TLR1, TLR5, and TLR11. Quantitative real-time PCR revealed that all OpTLRs were expressed in the examined tissues, especially the immune system-related tissues, such as the spleen, gill, head kidney, and middle kidney. The expression of OpTLRs was high at the early stage of development (5 days posthatching [dph]) and decreased gradually until 30 dph. We speculated that maternal immunity or the developmental function of TLRs played an important protective role in the early stage. However, from 30 to 60 dph, TLR expression was low. At this time, juvenile fish are susceptible to viruses and begin to show TLR self-expression with weak immunity. Artificial immunity enhancement is needed to improve the environmental resistance of juvenile fish. In summary, our results not only provide valuable basic data for future studies of the TLR gene family in Oplegnathidae fish but also lay a solid foundation for Oplegnathidae fish research.

Congenital Infections: Priorities and Possibilities for Resource-limited Settings.

Congenital Infections: Priorities and Possibilities for Resource-limited Settings.

Maternal COVID-19 Disease and COVID-19 Immunization.

AimThis study aimed to evaluate the immune response and vertical transmission of anti-severe acute respiratory syndrome (SARS) antibodies in vaccinated, expectant mothers infected with coronavirus disease 2019 (COVID-19) and to study the sequelae.Study designThis was a retrospective study of pregnant women conducted at Bahrain Defense Force Hospital from March 2021 to September 2021. The study population was divided into two groups: group 1 was vaccinated with Sinopharm or Pfizer/BioNTech during pregnancy and never infected with COVID-19. Group 2 was unvaccinated and had been infected with COVID-19. Immune responses such as anti-nucleocapsid (anti-N) and anti-spike (anti-S) from paired samples of maternal and umbilical cord blood were measured with Elecsys immunoassay (Roche Holding AG: Basel, Switzerland) at the time of delivery. Obstetric complications such as preterm labor, preeclampsia, and stillbirth were assessed. Analysis was performed using SPSS version 26.0 (IBM Corp: Armonk, NY) and Minitab version 18 (Minitab, LLC: State College, PA). A p-value of less than 0.05 was considered statistically significant.ResultsThe study included 90 vaccinated and 90 COVID-19-recovered pregnant women. Matched samples were available for 80 vaccinated and 74 COVID-19-recovered women. Group 1 had significantly higher levels of anti-S for both the mother and the cord blood and a significantly higher transfer ratio of anti-S. Group 2 had higher levels of anti-N. In group 1, the paired sample titer of anti-S had a weak negative correlation with maternal age whereas, in group 2, the mother’s anti-N had a weak positive correlation with age. Antibodies of COVID-19-recovered mothers and cord blood had a moderate negative correlation with gestational age, except for the mother’s anti-N. In group 1, the transfer ratio of anti-N and anti-S had a statistically significant association with gestational age. Preterm delivery had a high prevalence of anti-transfer ratios of <1, and delivery at >37 weeks had a high prevalence of ≥1. In group 2, 90% of preterm deliveries had transfer ratios of anti-S <1. The latency period of the COVID-19 group had a statistically significant association with the antibody transfer ratio. An interval of less than 100 days had a high prevalence in the ratio of <1. An interval of more than 100 days had a high prevalence in the ratio of ≥1. There was no significant latency period in group 1. Group 1 had a 75% prevalence of an anti-S transfer ratio ≥1 with a birth weight of >3500 g; group 2 had no significance in birth weight. We did not find significance in the sequelae of morbidities in either group.ConclusionThe production of the antibody N in the COVID-19-infected and antibody S in the vaccinated pregnant women as well as the vertical transmission of antibodies was efficacious. Significant variation was found regarding maternal age in both groups. The transfer ratio of the antibodies in the vaccinated and COVID-19-recovered women was significantly higher in terms of babies of the vaccinated and the infected population. The transfer ratios were distinct according to the latency period and birth weight of the infants.

Knowledge and attitudes of pregnant women on maternal immunization against COVID-19 in Croatia.

The aim of this study was to assess pregnant women's knowledge and attitudes regarding maternal COVID-19 immunization during pregnancy. A cross-sectional study was performed in two teaching hospitals between May and October 2021 in Zagreb, Croatia. During antenatal clinic visit pregnant women were approached and asked to fill out a predesigned questionnaire about their knowledge and attitudes towards COVID-19 vaccination. Collected data was later analyzed. A total of 430 women participated in the study. Only 16% of women expressed their willingness to be vaccinated against COVID-19 if offered, despite that 71% of them believe that COVID-19 might be a serious illness in pregnant women. The most important obstacle in having better acceptance of the vaccines is in the assumption that the vaccines are not safe for pregnant women (73%) or the fetus (75%), or that the vaccines are not effective (41%). The relationship exists between acceptance of vaccination in general and willingness to get other vaccines in pregnancy and readiness to be vaccinated against COVID-19 in pregnancy. Only one out of 55 women who were not adherent to the current vaccination recommendations in Croatia would accept the COVID-19 vaccine during pregnancy if offered. 21 (5%) women stated that vaccination against influenza and pertussis during pregnancy is necessary and 13 (62%) of them would get vaccinated against COVID-19 if offered. This study showed that the crucial reasons for refusing vaccination against COVID-19 among pregnant women in Croatia are the concerns about the vaccines' effectiveness and safety. All healthcare providers should put more effort into education of pregnant women on risks of COVID-19, as well as on the benefits and safety of the vaccines.

Optimization of Timing of Maternal Pertussis Immunization From 6 Years of Postimplementation Surveillance Data in England.

England's third-trimester maternal pertussis vaccination, introduced in October 2012, was extended to the second trimester in 2016. Maternal vaccination provides high protection against infant disease, but routine second-trimester vaccination has not previously been assessed. National laboratory-confirmed pertussis case surveillance determined vaccination history, maternal vaccination history and hospitalization. Pertussis hospital admissions between 2012 and 2019 were extracted from the Hospital Episode Statistics data set. Vaccine effectiveness (VE) was calculated for pertussis case patients born between October 2012 and September 2018 using the screening method and matching with a nationally representative data set. Higher coverage was observed after earlier maternal vaccination with approximately 40% of pregnant women vaccinated ≥13 weeks before delivery. Cases and hospitalizations stabilized at low levels in younger infants but remained elevated in older infants, children, and adults. No deaths occurred in infants with vaccinated mothers after 2016. Of 1162 laboratory-confirmed pertussis cases in the study, 599 (52%) were in infants aged <93 days: 463 (77%) with unvaccinated and 136 (23%) with vaccinated mothers. The VE was equivalent in infants with mothers vaccinated at different gestational periods except in those with mothers vaccinated between 7 days before and 41 days after delivery. Children whose mothers were unvaccinated but with vaccination in a previous pregnancy had a VE against disease of 44% (95% confidence interval, 19%-75%). There was no increased disease risk after primary vaccination in children with mothers vaccinated at least 7 days before delivery. National policy recommending vaccination in the second trimester increased earlier maternal vaccine uptake with sustained high VE and impact against early infant disease.

How COVID‐19 has impacted immunisation service delivery in Australia: a national study

Objective:The objective of this study was to determine the impact the COVID‐19 pandemic had on the delivery of adult, maternal and childhood immunisation services in Australia in 2020 prior to the rollout of COVID‐19 vaccines, and to understand the adaptations made at a service delivery level that may have contributed to the successful delivery of immunisation services during the first year of the pandemic. Methods:An electronic survey was sent to immunisation providers and pharmacists in all states and territories in Australia between November 2020 and December 2020. It explored interruption to the delivery of immunisation services, strategies implemented to maintain services, prioritisation of populations, and self‐reported challenges and solutions initiated by providers. Results:A total of 850 people responded to the survey. Of these, the most common professional groups identified were pharmacists followed by nurse immunisers, nurses/midwives and general practitioners. Several changes were implemented including relocation of vaccination clinics, change to bookings rather than walk‐in appointments, infection prevention measures, clients waiting in cars pre‐ and post‐vaccination and reduced observation period post‐vaccination. Conclusion:The pandemic has provided opportunities for services to trial new and innovative strategies such as electronic pre‐assessment, electronic consent and drive‐through vaccination services. Implications for public health:Immunisation providers mostly viewed these changes positively and intend to continue many post‐pandemic. The experience gained from the trialling of these strategies may be adapted for vaccine delivery and National Immunisation Program vaccines beyond the pandemic.

Maternal RSV Immunization During Pregnancy

Maternal RSV Immunization During Pregnancy

Maternal prenatal immunity, neonatal trained immunity, and early airway microbiota shape childhood asthma development.

The path to childhood asthma is thought to initiate in utero and be further promoted by postnatal exposures. However, the underlying mechanisms remain underexplored. We hypothesized that prenatal maternal immune dysfunction associated with increased childhood asthma risk (revealed by low IFN-γ:IL-13 secretion during the third trimester of pregnancy) alters neonatal immune training through epigenetic mechanisms and promotes early-life airway colonization by asthmagenic microbiota. We examined epigenetic, immunologic, and microbial features potentially related to maternal prenatal immunity (IFN-γ:IL-13 ratio) and childhood asthma in a birth cohort of mother-child dyads sampled pre-, peri-, and postnatally (N=155). Epigenome-wide DNA methylation and cytokine production were assessed in cord blood mononuclear cells (CBMC) by array profiling and ELISA, respectively. Nasopharyngeal microbiome composition was characterized at age 2-36 months by 16S rRNA sequencing. Maternal prenatal immune status related to methylome profiles in neonates born to non-asthmatic mothers. A module of differentially methylated CpG sites enriched for microbe-responsive elements was associated with childhood asthma. In vitro responsiveness to microbial products was impaired in CBMCs from neonates born to mothers with the lowest IFN-γ:IL-13 ratio, suggesting defective neonatal innate immunity in those who developed asthma during childhood. These infants exhibited a distinct pattern of upper airway microbiota development characterized by early-life colonization by Haemophilus that transitioned to a Moraxella-dominated microbiota by age 36 months. Maternal prenatal immune status shapes asthma development in her child by altering the epigenome and trained innate immunity at birth, and is associated with pathologic upper airway microbial colonization in early life.

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

With SARS-CoV-2 infection, pregnant women may be at a high risk of severe disease and adverse perinatal outcomes. A COVID-19 vaccination campaign represents the key strategy to combat the pandemic; however, public acceptance of maternal immunization has to be improved, which may be achieved by highlighting the promising mechanism of passive immunity as a strategy for protecting newborns against SARS-CoV-2 infection. We tested the anti-SARS-CoV-2 antibody response following COVID-19 full-dose vaccination in the serum and amniotic fluid of two pregnant women who presented between April and June 2021, at the Center for the Treatment and Prevention of Infections in Pregnancy of the National Institute for Infectious Diseases “L. Spallanzani”, for antenatal consultancy. Anti-SARS-CoV-2 IgG was found in residual samples of amniotic fluid collected from both women at the 18th week of gestation (63 and 131 days after the second dose’s administration). Titers in amniotic fluid mirrored the levels detected in serum and were inversely linked to the time from vaccination. Our results suggest that antibodies elicited by COVID-19 vaccination can cross the placenta and reach the fetus; therefore, they may offer passive immunity at birth. It is critical to fully understand the kinetics of the maternal response to vaccination, the efficiency of IgG transfer, and the persistence of antibodies in infants to optimize maternal immunization regimens.

Assessment of the duration of maternal-derived antibodies specific to the Mycoplasma agalactiae vaccine in goat kids.

BackgroundContagious agalactia (CA) is one of the most important diseases in the small ruminant industry in Iran. The historical aetiology of this disease is Mycoplasma agalactiae (Ma). The main way to control this disease, in addition to management measures, is vaccination. In ruminant newborns, determining the age of first vaccination against Ma is a challenge due to the interference between colostrum‐derived maternal immunity and vaccination‐induced immunity. The aim of this study was to evaluate the consistency of maternal‐derived antibodies specific to the Ma in goat kids blood serum born from the vaccinated does.ObjectivesDtermination of level of antibody against Ma in goat kids born from vaccinated dams against Ma. Assessment of duration of protective level of maternal derived antibody in goat kids serum, after receiving colostrum from vaccinted mother with Ma vaccine. Determination the best time vaccination against Ma in goat kids receiving colostrum from vaccinated dams.Methods20 Saanen goat kids were studied in two groups of 10 animals including control (receiving colostrum from unvaccinated does) and treatment (receiving colostrum from vaccinated does). Indirect Elisa was used to evaluate serum specific antibodies to Ma in goat kids (control and treatment groups) from birth to 100 days of age.ResultsAfter receiving a sufficient amount of colostrum, the goat kids in the treatment group had a significantly higher S/P% than the control group until 56 days after birth (p < 0.05) and at 70–100 days after birth, there was no significant difference between the treatment and control groups (p > 0.05).ConclusionsThis study showed that 56–70 days of age could be a good age to give the first dose of CA vaccine in goat kids, but more studies are needed on the effectiveness of this vaccine at this age.

COVID-19 booster dose induces robust antibody response in pregnant, lactating, and nonpregnant women

BackgroundAlthough emerging data during the SARS-CoV-2 pandemic have demonstrated robust messenger RNA vaccine–induced immunogenicity across populations, including pregnant and lactating individuals, the rapid waning of vaccine-induced immunity and the emergence of variants of concern motivated the use of messenger RNA vaccine booster doses. Whether all populations, including pregnant and lactating individuals, will mount a comparable response to a booster dose is not known.ObjectiveThis study aimed to profile the humoral immune response to a COVID-19 messenger RNA booster dose in a cohort of pregnant, lactating, and nonpregnant age-matched women.Study DesignThis study characterized the antibody response against ancestral Spike and Omicron in a cohort of 31 pregnant, 12 lactating, and 20 nonpregnant age-matched controls who received a BNT162b2 or messenger RNA-1273 booster dose after primary COVID-19 vaccination. In addition, this study examined the vaccine-induced antibody profiles of 15 maternal-to-cord dyads at delivery.ResultsReceiving a booster dose during pregnancy resulted in increased immunoglobulin G1 levels against Omicron Spike (postprimary vaccination vs postbooster dose; P=.03). Pregnant and lactating individuals exhibited equivalent Spike-specific total immunoglobulin G1, immunoglobulin M, and immunoglobulin A levels and neutralizing titers against Omicron compared with nonpregnant women. Subtle differences in Fc receptor binding and antibody subclass profiles were observed in the immune response to a booster dose in pregnant vs nonpregnant individuals. The analysis of maternal and cord antibody profiles at delivery demonstrated equivalent total Spike-specific immunoglobulin G1 in maternal and cord blood, yet higher Spike-specific FcγR3a-binding antibodies in the cord relative to maternal blood (P=.002), consistent with the preferential transfer of highly functional immunoglobulin. Spike-specific immunoglobulin G1 levels in the cord were positively correlated with the time elapsed since receiving the booster dose (Spearman R, .574; P=.035).ConclusionStudy data suggested that receiving a booster dose during pregnancy induces a robust Spike-specific humoral immune response, including against Omicron. If boosting occurs in the third trimester of pregnancy, higher Spike-specific cord immunoglobulin G1 levels are achieved with greater time elapsed between receiving the booster and delivery. Receiving a booster dose has the potential to augment maternal and neonatal immunity.

Plasticity of natural killer cells in pregnant patients infected with SARS-CoV-2 and their neonates during childbirth.

The COVID-19 pandemic has occurred due to infection caused by the SARS-CoV-2 coronavirus, which impacts gestation and pregnancy. In SARS-CoV-2 infection, only very rare cases of vertical transmission have been reported, suggesting that fetal immune imprinting due to a maternal infection is probably a result of changes in maternal immunity. Natural killer (NK) cells are the leading maternal immune cells that act as a natural defense system to fight infections. They also play a pivotal role in the establishment and maintenance of pregnancy. While peripheral NK cells display specific features in patients infected with SARS-CoV-2 in the general population, information remains elusive in pregnant mothers and neonates. In the present study, we analyzed the characteristics of NK cells isolated from both neonatal umbilical cord blood and maternal peripheral blood close to the time of delivery. Phenotype and functions were compared in 18 healthy pregnant women and 34 COVID-19 patients during pregnancy within an ongoing infection (PCR+; N = 15) or after recovery (IgG+PCR−; N = 19). The frequency of NK cells from infected women and their neonates was correlated with the production of inflammatory cytokines in the serum. The expression of NKG2A and NKp30, as well as degranulation of NK cells in pregnant women with ongoing infection, were both negatively correlated to estradiol level. Furthermore, NK cells from the neonates born to infected women were significantly decreased and also correlated to estradiol level. This study highlights the relationship between NK cells, inflammation, and estradiol in patients with ongoing infection, providing new insights into the impact of maternal SARS-CoV-2 infection on the neonate.

EVALUATION OF MATERNAL AND NEONATAL IGG AND IGM SARS-COV-2 ANTIBODIES, TRANSFER RATIOS OF ANTIBODIES VIA PLACENTA, IMMUNE RESPONSE IN NEONATES BY IGG AND IGA SARS-COV-2 ANTIBODIES DETECTION

Objective: To study SARS-CoV-2 viral load in maternal and neonatal bodily fluids, Passage of anti-SARS-CoV-2 antibody through placenta and breastmilk, and incidence of fetoplacental infection.&#x0D; Methods: The data were gathered from five databases and included a review of research articles published between 2020 and 2021.&#x0D; &#x0D; PubMed&#x0D; Google Scholar&#x0D; &#x0D; The following terms were used in the search: 1. Clinical symptoms of the mother, 2. The ratio of negative to positive RT-PCR test results in infants, 3. Ratios of normal to aberrant IgG and IgM, 4. Antibody Placental Transfer, 5. Time period for maternal immunization to produce effective antibodies, 6. Neonatal Immune Response, 7. Antibodies are transferred through breast milk after moms have been immunised.&#x0D; Results: Several prospective and retrospective studies conducted in Wuhan, Philadelphia, Florida and Massachusetts consisted of seropositive as well as seronegative pregnant women. SARS-CoV-2 antibodies were detected in the sera of the mother and correlated with the antibodies detected in the neonatal blood. Significant transfer of IgG SARS-CoV-2 antibodies through placenta and breast milk was observed; that is, positive correlation was found between SARS-CoV-2 IgG concentrations in cord and maternal sera (r = 0.886; P &lt; .001). Not only passively, but mothers infected during the peripartum period protect the newborn by actively stimulating and training the neonate system via breastmilk immune complexes.&#x0D; Conclusion: We here highlight novel insights arising from recent research endeavours on the transmission of SARS-CoV-2 antibodies from a mother to an infant.

Multi-tiered intervention to increase maternal immunization coverage: A randomized, controlled trial

ObjectiveTo evaluate the impact of a multi-component intervention package of maternal immunization uptake in obstetric care clinics. MethodsIn a multi-level, cluster- and individually-randomized controlled trial we implemented an evidence-based intervention that targeted practice-, provider- and patient-level barriers to vaccine uptake. Obstetric practices were randomized to receive the practice and provider-level interventions or continue their normal standard of care. We enrolled pregnant women at practices in Georgia and Colorado and randomized women into patient-level intervention and control groups, resulting in four study arms. The primary outcomes were receipt of the influenza and tetanus, diphtheria and acellular pertussis (Tdap) vaccines during pregnancy. A sample size of 550 women per arm (2200 total) was planned and enrolled to compare the intervention between the four study arms. ResultsBetween June 2017 and July 2018, 4907 women were screened and 2200 women were randomized, 550 to each of the four study arms. We were unable to follow-up with 108 women, for a final sample size of 2092. Sample characteristics and sample size were similar among study arms. There was no significant increase in Tdap or influenza vaccine uptake overall. Among women who had no intention of or were unsure about receiving the influenza vaccine during pregnancy, those who received just the patient-level intervention were 61% more likely to receive the influenza vaccine than those in the control arm (Relative risk: 1.61; 95% Confidence Interval: 1.18–2.21). There was no significant difference in vaccine uptake for either influenza or tetanus, diphtheria and acellular pertussis between the four arms of the study. ConclusionsThis trial highlights the need for more targeted interventions to improve vaccine uptake. Future work should focus on clinics with low baseline vaccine uptake and the patient-level intervention should be expanded and targeted towards women with low vaccine confidence.

Cord Blood SARS-CoV-2 IgG Antibodies and Their Association With Maternal Immunity and Neonatal Outcomes.

Passive transplacental immunity is crucial for neonatal protection from infections. Data on the correlation between neonatal immunity to SARS-CoV-2 and protection from adverse outcomes is scarce. This work aimed to describe neonatal seropositivity in the context of maternal SARS-CoV-2 infection, seropositivity, and neonatal outcomes. This retrospective nested case-control study enrolled high-risk pregnant women with a SARS-CoV-2 RT-PCR positive test who gave birth at the Instituto Nacional de Perinatología in Mexico City and their term neonates. Anti-SARS-CoV-2 IgG antibodies in maternal and cord blood samples were detected using a chemiluminescent assay. In total, 63 mother-neonate dyads (mean gestational age 38.4 weeks) were included. Transplacental transfer of SARS-CoV-2 IgG occurred in 76% of neonates from seropositive mothers. A positive association between maternal IgG levels and Cycle threshold (Ct) values of RT-qPCR test for SARS-CoV-2 with neonatal IgG levels was observed. Regarding neonatal outcomes, most seropositive neonates did not require any mechanical ventilation, and none developed any respiratory morbidity (either in the COVID-19 positive or negative groups) compared to 7 seronegative neonates. Furthermore, the odds of neonatal respiratory morbidity exhibited a tendency to decrease when neonatal IgG levels increase. These results add further evidence suggesting passive IgG transfer importance.

O-054 COVID-19 during pregnancy, maternal immune response and neonatal cell-specific immunity

Pathogens are a major threat to maternal health and the progression of pregnancy. The immune response during normally progressing pregnancies, primarily the suppression of inflammation, likely accounts for this high susceptibility of pregnant women to infections. An increased morbidity and mortality related to influenza, COVID-19 and malaria has been reported for pregnant women, compared to non-pregnant women. Especially influenza infections during pregnancy have been well studied, as humans are severely and recurrently affected by seasonal epidemics and random pandemics. Besides severe maternal symptoms such as acute cardiopulmonary events, pneumonia, and acute respiratory distress syndrome, maternal influenza infection also causes foetal complications, such as intrauterine growth restriction, preterm birth or even foetal death. However, vertical transmission of the influenza virus across the placenta and infection of the foetus has not been observed, suggesting that the pregnancy pathologies are maternally derived.In addition to influenza-mediated adverse conditions, the recent COVID-19 pandemic has underscored that infection with the severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) can also lead to severe illnesses in pregnant women, accompanied by a higher risk for foetal loss or preterm birth. Fortunately, with the ongoing pandemic, large cohort studies and meta-analyses revealed that vertical transmission and related fetal infection is a rare complication affecting only 1-3% of SARS-CoV-2 infections in pregnancy. These low risk for placental infection is likely due to the inefficient SARS-CoV-2 virus replication in placental tissues. Since understanding SARS-CoV-2-related pathogenicity during pregnancy is highly relevant, we initiated a study early in 2020, to which we have recruited more than 160 pregnant women with COVID-19. Our comprehensive placental analyses unearthed a paucity of SARS-CoV-2 viral expression ex vivo in term placentae under acute infection and in convalescent pregnant women. Furthermore, we could show inefficient SARS-CoV-2 replication in placental tissues in vitro, which provides a rationale for the low ex vivo viral expression. We detected specific SARS-CoV-2 T cell responses in mothers within a few days upon infection, which is undetectable in cord blood. Reports by others have shown that maternal SARS-CoV-2 during pregnancy may cause placental insufficiency, defined by increased perivillous fibrin deposition, histiocytic intervillositis and trophoblast necrosis. These changes can cause extensive placental damage leading to placental malperfusion and insufficiency that is incompatible with intrauterine survival. Considering that multiple SARS-CoV-2 variants of concern which emerged until today may affect pregnant women differently and bear a differential risk for pregnancy complication. This, continuous vigilance is needed in order to provide best protection of the highly vulnerable group of pregnant women and their unborn children.Trial registration number

Seroprevalence of antibodies to classical swine fever virus and porcine reproductive and respiratory syndrome virus in healthy pigs in Hunan Province, China.

Classical swine fever (CSF) and porcine reproductive and respiratory syndrome (PRRS) are responsible for major economic losses and represent a threat to the swine industry worldwide. Routine surveillance serology for CSF and PRRS viruses is critical to maintaining the health status of sow farms in Hunan Province, which is one of the top pig production provinces in China. The aim of our study was to investigate the serological statistics of CSF virus (CSFV) and PRRS virus (PRRSV) in Hunan Province. The cohort serum samples were collected from vaccinated and unvaccinated pigs. Our findings showed that the average rates of CSFV and PRRSV antibody seropositivity were 82.2% (95% CI: 80.1-84.3) and 84.8% (95% CI: 82.5-87.1), respectively, in the immunized group and that these rates were higher than those in the unvaccinated group (58.6% for CSFV and 47.8% for PRRSV). Additionally, the level of CSFV antibody in piglet serum declined gradually with age, whereas PRRSV-specific antibody level increased initially (1 to 2 weeks old) and then declined with age (2 to 4 weeks old). In summary, we investigated the difference in CSFV/PRRSV antibody levels among piglets at various weeks old (1 to 4 weeks) to further establish the duration of maternal immunity in piglets. In addition, routine monitoring of CSFV/PRRSV antibodies in immunized pigs was carried out to evaluate the efficacy of vaccination.