Maternal Immunization Research Articles

Dam Age Differentially Affects Immune Response of Her Calf to Bovine Respiratory Disease Vaccination

Understanding the biological factors that affect immunological responses may be beneficial in developing more effective bovine respiratory disease vaccination strategies. Dam traits, such as age and vaccination history, are not considered when developing vaccination protocols or assessing vaccination efficacy, even though both factors may influence the transference of passive immunity; therefore, a preliminary study was conducted to determine the effect of dam age on the immune response of their calves to vaccinations. Calves born to dams of various ages were vaccinated with a modified live vaccine at 3 to 4 months old, revaccinated with either the same modified live or an inactivated vaccine at weaning, and boosted with the same vaccine 28 days later. Immune and cortisol measures were taken upon initial vaccination, revaccination at weaning, and then 14 and 28 days post-revaccination and post-booster. Overall, calves from older-aged dams began to exhibit a pattern indicative of a dampened immunoglobulin-G response to revaccination and booster, regardless of vaccination type. In contrast, calves from the youngest and oldest dams who received one modified live and two inactivated vaccines had the highest serum-neutralizing titers for most antigens present in the vaccines. These preliminary data partly imply that it may be plausible that the more doses of modified live vaccines the dam receives, which increase with each pregnancy, may affect the immune response of her progeny to vaccination at weaning and revaccination. This may be due to the effects on maternal passive immunity and is further affected by the type of vaccination her progeny received for some measures. However, more research is necessary to elucidate further the effects biological factors have on the immune response to vaccination, develop better vaccination strategies, and further validate these findings through increased sample sizes.

Stunting: Penyebab, Gejala, dan Pencegahan

Currently, the Indonesian government has a target of reducing stunting rates. Stunting is a condition where there is malnutrition in children where children around the world suffer from stunting. This research uses a literature review with data collection sources coming from scientific articles, theses, books, theses. Stunting occurs due to many factors, namely maternal education, economy, immunization, breastfeeding, and infectious diseases. Stunting can be prevented by breastfeeding, immunization, diet, and health checks.

Role of Folic Acid, Vitamin D, and Progesterone in Pregnancy and Threatened Abortion

The most frequent early pregnancy problem threatened abortion, affects 20% of pregnancies. Vaginal bleeding may be present, together with or without abdominal cramps. Women who are getting older, smoking, being overweight or obese, having PCOS, and having had an abortion in the past are danger signs for a potential abortion. The Physiology of the disease has been linked to alterations in cytokine concentrations or weakened maternal immunity. By taking the clinical history into account, determine the therapy options and provide crucial information for the prognosis, the physical examination, the biochemistry of the mother's serum, and the results of the ultrasound. The most popular advice is to stay in bed, but its usefulness is not well supported. Progesterone, vitamin D, and folic acid are further alternatives.

The PRotective Effect of Maternal Immunisation on preTerm birth: characterising the Underlying mechanisms and Role in newborn immune function: the PREMITUR study protocol.

Maternal immunisation, a low cost and high efficacy intervention is recommended for its pathogen specific protection. Evidence suggests that maternal immunisation has another significant impact: reduction of preterm birth (PTB), the single greatest cause of childhood morbidity and mortality globally. Our overarching question is: how does maternal immunisation modify the immune system in pregnant women and/or their newborn to reduce adverse pregnancy outcomes and enhance the newborn infant's capacity to protect itself from infectious diseases during early childhood? To answer this question we are conducting a multi-site, prospective observational cohort study collecting maternal and infant biological samples at defined time points during pregnancy and post-partum from nulliparous women. We aim to enrol 400 women and determine the immunetrajectory in pregnancy and the impact of maternal immunisation (including influenza, pertussis and/or COVID-19 vaccines) on this trajectory. The results are expected to identify areas that can be targeted for future intervention studies.

The maternal gut microbiome in pregnancy: implications for the developing immune system.

The gut microbiome has important roles in host metabolism and immunity, and microbial dysbiosis affects human physiology and health. Maternal immunity and microbial metabolites during pregnancy, microbial transfer during birth, and transfer of immune factors, microorganisms and metabolites via breastfeeding provide critical sources of early-life microbial and immune training, with important consequences for human health. Only a few studies have directly examined the interactions between the gut microbiome and the immune system during pregnancy, and the subsequent effect on offspring development. In this Review, we aim to describe how the maternal microbiome shapes overall pregnancy-associated maternal, fetal and early neonatal immune systems, focusing on the existing evidence and highlighting current gaps to promote further research.

Maternal immune factors involved in the prevention or facilitation of neonatal bacterial infections

Newborns, whether born prematurely or at term, have a fully formed but naive immune system that must adapt to the extra-uterine environment to prevent infections. Maternal immunity, transmitted through the placenta and breast milk, protects newborns against infections, primarily via immunoglobulins (IgG and IgA) and certain maternal immune cells also known as microchimeric cells.Recently, it also appeared that the maternal gut microbiota played a vital role in neonatal immune maturation via microbial compounds impacting immune development and the establishment of immune tolerance.In this context, maternal vaccination is a powerful tool to enhance even more maternal and neonatal health. It involves the transfer of vaccine-induced antibodies to protect both mother and child from infectious diseases.In this work we review the state of the art on maternal immune factors involved in the prevention of neonatal bacterial infections, with particular emphasis on the role of maternal vaccination in protecting neonates against bacterial disease.

Effective and safe transfer of maternal antibodies persisting two months postpartum following maternal immunization with different doses of recombinant pertussis-containing vaccines

IntroductionRecombinant acellular pertussis (ap) vaccines containing genetically inactivated pertussis toxin (PTgen) and filamentous hemagglutinin (FHA) with or without tetanus (TT) and diphtheria (DT) vaccines (Td) were found safe and immunogenic in non-pregnant and pregnant women. We report here maternal antibody transfer and safety data in mothers and neonates. MethodsThis is the follow up of a phase 2 trial in 2019 among 400 pregnant women who randomly received one dose of recombinant pertussis-only vaccine containing 1 µg PTgen and 1 µg FHA (ap1gen), or Td combined with ap1gen (Tdap1gen), or with 2 µg PTgen and 5 µg FHA (Tdap2gen), or with 5 µg PTgen and 5 µg FHA (TdaP5gen, Boostagen®, BioNet, Thailand) or chemically-inactivated acellular pertussis comparator (Tdap8chem, Boostrix™, GSK, Belgium), either in the second or third trimester of gestation. IgG against PT, FHA, TT and DT were assessed by ELISA, PT-neutralizing antibodies (PTNA) by Chinese Hamster Ovary cell assay and safety outcomes at delivery in mothers and at birth. ResultsAnti-PT and anti-FHA geometric mean concentration (GMC) ratio between infants at birth and mothers at delivery was above 1 in all groups. PT GMC in infants at birth were ≥30 IU/mL in all groups with the highest titers in infants found in TdaP5gen group at birth (118.8 [95% CI 93.9–150.4]). At 2 months, PT GMC ratio to Tdap8chem (98.75% CI) was significantly higher for TdaP5gen (2.6 [1.7–4.0]) and comparable for other recombinant vaccines. No difference in PTNA titers at birth was observed between all groups nor between time of vaccination. Adverse events were comparable in all vaccine groups. ConclusionsBioNet licensed (TdaP5gen and Tdap2gen) and candidate vaccines (Tdap1gen and ap1gen) when given to pregnant women in the second or third trimester of gestation are safe and have induced passive pertussis immunity to infants.

Rancangan video animasi edukasi kesiapsiagaan bencana non alam COVID-19 bagi ibu hamil. Uji validitas dan reliabilitas instrumen

Background: COVID-19 is transmitted through air transmission. Prevention of transmission of the COVID-19 virus in pregnant women will certainly reduce complications in pregnant women and the fetus. An educational animated video design can help increase pregnant women's understanding of preventing the transmission of COVID-19. The Coronavirus disease 2019 or COVID-19 in pregnant women will increase the risk of severe infection and pregnancy complications such as preterm labour. Pregnancy will cause physiological changes and maternal immunity, so pregnant women are in a high-risk group for COVID-19 infection. Prevention of COVID-19 virus transmission in pregnant women needs to be done to prevent complications in pregnant women and fetuses. Research objectives: The design of educational animated videos can help increase the understanding of pregnant women in preventing COVID-19 transmission and to test the validity and reliability of instruments.Method: Developing an educational video animation for non-natural disaster preparedness is carried out in several stages, namely making scenarios, storyboards, sketches, choosing colors, coloring, layering and combining them into animated videos. Then, the animated video was validated by a team of experts from the Langsa City Health Office. The content of this video is about preventing COVID-19 transmission in pregnant women. The animated video was tested on 20 respondents in June 2021 in Karang Anyar village, Langsa City. Furthermore, the instrument was tested for validity and reliability on 20 respondents in July 2021 in Paya Bujok Tunong Village, Langsa City.Results: Are 10 components assessed from educational animated videos, and the majority are very good ≥65%. The results of the validity and reliability tests show that the questionnaire is suitable for use in the condition of pregnant women when facing COVID-19 (p > 0,05). However, one invalid statement item was found. The reliability test results show that all variables have an alpha value above 0,378.Conclusion: Respondents can use and distribute animated videos and research instruments.

New Insights on Respiratory Syncytial Virus Prevention.

Respiratory syncytial virus (RSV) is a well-known infant pathogen transmitted mainly by droplets. It is a leading cause of upper respiratory tract infections in children, usually with a mild course of illness. RSV has also been a threat to older people, especially those with underlying medical conditions. For a long time, prevention was limited to passive immunoprophylaxis with palivizumab for high-risk infants. There was a strong need to find other treatment or prevention methods against RSV infections. In addition, after the coronavirus disease 2019 (COVID-19) pandemic, some significant changes in RSV epidemiology have been observed. Researchers noticed the shift in RSV seasonality and age distribution and the increased number of cases in older infants and adults. All of these made the need to find other medical options even stronger. Fortunately, two protein-based vaccines against RSV have successfully passed all phases of clinical trials and have been approved for use by adults and older people. One of them is also approved for infants from birth to 6 months of age (after maternal immunisation during pregnancy) and for pregnant women between 24 and 36 weeks of pregnancy. Also, a new passive immunisation option named nirsevimab (a highly potent monoclonal antibody with a long half-life) is now available for the paediatric group. In this review, we will discuss the previous and current RSV prevention methods in the light of structural discoveries of RSV antigens.

Immunomodulatory Effects of Transfusions on Maternal Immunity in Pregnancy

Pregnancy represents a unique immunological state where maternal immune adaptations play a pivotal role in supporting fetal development while maintaining tolerance to the semi-allogeneic fetus. Blood transfusions, often necessary during pregnancy for various medical conditions, present an intriguing avenue for understanding alterations in maternal immunity. This comprehensive review aims to elucidate the intricate immunomodulatory effects of blood transfusions on maternal immunity during pregnancy. Beginning with an exploration of normal immunological changes in pregnancy, this review navigates through the immunomodulatory challenges posed by blood transfusions. The impact of donor factors, transfusion-related immunological components, and their influence NEWPORT INTERNATIONAL JOURNAL OF BIOLOGICAL AND APPLIED SCIENCES (NIJBAS) Volume 3 Issue 3 2023 ©NIJBAS Publications 2023 OPEN ACCESS ONLINE ISSN: 2992-5797 PRINT ISSN: 2992-6122 ©Obeagu et al., 2023 This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Page | 2 on the maternal immune system are scrutinized. Mechanistic insights into altered cytokine responses, adaptive immune changes, and the role of regulatory T cells post-transfusion form critical focal points. Clinically, discerning the implications of altered maternal immunity on fetal, neonatal health, and obstetric outcomes is essential. Assessing risks and benefits associated with transfusions in pregnancy further underscores the clinical relevance of understanding these immunomodulatory effects. Despite advancements, this review acknowledges research gaps and limitations, highlighting the need for future investigations. Recommendations for prospective studies and potential clinical implications conclude this review, emphasizing the significance of comprehending immunomodulation in maternal immunity post-transfusion for optimizing maternal-fetal health. In conclusion, this review encapsulates current knowledge, challenges, and future directions in comprehending the complex interplay between blood transfusions and maternal immune responses during pregnancy, offering valuable insights into a crucial aspect of perinatal medicine. Keywords: blood transfusions; maternal immunity; pregnancy; immunomodulation; cytokines; alloimmunization; inflammation; transplacental immunomodulation

2079. Maternal hybrid immunity to SARS-CoV-2 during pregnancy provides more durable infant antibody responses compared to natural infection alone

Abstract Background Immunity from natural infection and vaccination (hybrid) may provide more durable SARS-CoV-2 antibody responses; whether this increases durability of maternally-derived antibody responses in infants is unknown. Methods Participants with prior SARS-CoV-2 infection in pregnancy (anti-nucleocapsid [anti-N] IgG+ on enrollment or prior RT-PCR+ or antigen+) were enrolled between January 2021-August 2022. Blood samples collected in pregnancy, delivery/birth, 0-< 3 and 3-6 months postpartum were tested for anti-S+ IgG by Abbott Architect (positive: ≥50 AU/mL) and neutralizing antibodies (serum dilution inhibited infection by 50% [ND50 heat] ≥20 and R2 ≥0.9). Results Among 107 participants at enrollment in pregnancy, median age was 32 years (IQR 30-35) and median gestational age was 31 weeks (IQR 19.1–37.9). At delivery (median 19.7 weeks [IQR 14.3-30.0] from SARS CoV-2 diagnosis), unvaccinated participants and their infants were less likely to have anti-S IgG+ (maternal 87%; cord 86%) or neutralizing antibodies (maternal 86%; cord 75%) than vaccinated (≥1 dose) participants and their infants (maternal and cord both 100% anti-S IgG+ and neutralizing antibodies) (all p≤0.01). By 6 months of age, the proportion of infants of mothers who remained unvaccinated at birth with anti-S IgG+ and neutralizing antibody declined to 50% and 14% (anti-S IgG+ and neutralizing antibody, respectively) compared to 100% (anti-S IgG+ and neutralizing antibody) among infants with vaccinated mothers (all p< 0.01). Infants with anti-S IgG+ or neutralizing antibodies born to unvaccinated mothers had lower median antibody levels at birth (anti-S IgG log10 2.95 vs. 4.40 AU/ml; neutralization log10 1:2.37 vs. 1:4.00, all p< 0.01) and through 6 months of age (anti-S IgG log10 1.95 vs. 3.84 AU/ml, p< 0.01; log10 neutralization 1:1.34 vs. 1:3.20, p=0.11) vs. infants with mothers vaccinated prior to delivery. Neutralizing antibody responses among A) pregnant people with prior SARS-CoV-2 infection during pregnancy and B) their infants by maternal vaccination status *† *Among participants and their infants with positive neutralizing antibodies (ND50 heat ≥20 and R2 ≥0.9). †Maternal vaccination status is at time of blood sample collection; for infants refers to maternal vaccination status at time of delivery. Conclusion SARS-CoV-2 infection alone during pregnancy did not provide persistent antibody responses in infants through 6 months of age. Maternal vaccination provided more durable antibody responses in participants with prior SARS-CoV-2, potentially providing protection to vulnerable infants in the months prior to their own COVID-19 vaccine eligibility. Disclosures Sylvia M. LaCourse, MD, MPH, Merck: Grant/Research Support Alex L. Greninger, MD, PhD, MS, MPhil, Abbott Diagnostics: central testing|Cepheid: central testing|Hologic Inc: central testing|Janssen Infectious Disease: central testing|Novavax, Inc.: central testing|Pfizer, Inc.: central testing Alisa B. Kachikis, MD, MSc, Merck: Grant/Research Support|Pfizer: Grant/Research Support Janet A. Englund, MD, Ark Biopharma: Advisor/Consultant|AstraZeneca: Advisor/Consultant|AstraZeneca: Grant/Research Support|GlaxoSmithKline: Grant/Research Support|Meissa Vaccines: Advisor/Consultant|Merck: Grant/Research Support|Moderna: Advisor/Consultant|Moderna: Grant/Research Support|Pfizer: Advisor/Consultant|Pfizer: Grant/Research Support|Sanofi Pasteur: Advisor/Consultant Alison L. Drake, PhD, MPH, Merck: Grant/Research Support

Effects of light spectra on the ovarian maturation and maternal immunity in the little yellow croaker (Larimichthys polyactis)

Before spawning, fish ovaries undergo multiple events to prepare for embryogenesis. Although light plays a vital role in ovarian development and neuroendocrine activities, it is unclear how it affects ovarian maturation in the little yellow croaker (Larimichthys polyactis). This study aimed to investigate the influence of different light spectra [i.e., red, blue, dark, green, white, and ambient] on the gonadosomatic index (GSI) and hepatosomatic index (HSI); histology of the ovary; vitellogenin (VTG) levels in hepatic cells; plasma 17β-estradiol and growth hormone (GH) levels; total length; body weight; and innate/adaptive immune factors in captive-bred L. polyactis. The plasma 17β-estradiol levels gradually decreased from Jan 8 to Apr 9, and were higher in the red, green, and blue groups than in the white, dark, and control groups. By the end of the experiment, the VTG levels were significantly higher in the red group than in the control, white, and dark groups, while those in the blue group were the lowest among the treatments. The HSI fluctuated among the groups and was higher in the control, white, and green groups on Apr 9. The proportion of oocytes at stage IV was highest in the red group, which also exhibited the best synchronization of oocyte maturation. Maternal immunoglobulin M levels were significantly higher in the red and green groups than in the control, blue, dark, and white groups at the end of the experiment, while there was no significant difference in the complement component 3 (C3) levels. Collectively, these findings demonstrate that different light spectra affect 17β-estradiol secretion, VTG production, follicle synchronization and maternal immunity during ovarian maturation in L. polyactis.

A Virus-like Particle-Based F4 Enterotoxigenic Escherichia coli Vaccine Is Inhibited by Maternally Derived Antibodies in Piglets but Generates Robust Responses in Sows.

F4-positive enterotoxigenic Escherichia coli is associated with diarrhea and poor growth outcomes in neonatal and newly weaned piglets and is thus a major economic and welfare burden in the swine industry. Vaccination of sows with F4 fimbriae protects against the neonatal disease via passive transfer of maternal immunity. However, this strategy does not protect against infection post-weaning. Consequently, prevention and treatment methods in weaner pigs heavily rely on the use of antimicrobials. Therefore, in order to reduce antimicrobial consumption, more effective prophylactic alternatives are needed. In this study, we describe the development of a capsid virus-like particle (cVLP)-based vaccine targeting the major F4 fimbriae subunit and adhesion molecule, FaeG, and evaluate its immunogenicity in mice, piglets, and sows. cVLP-display significantly increased systemic and mucosal antibody responses towards the recombinant FaeG antigen in mice models. However, in piglets, the presence of anti-F4 maternally derived antibodies severely inhibited the induction of active humoral responses towards the FaeG antigen. This inhibition could not be overcome, even with the enhanced immunogenicity achieved via cVLP display. However, in sows, intramuscular vaccination with the FaeG.cVLP vaccine was able to generate robust IgG and IgA responses that were comparable with a commercial fimbriae-based vaccine, and which were effectively transferred to piglets via colostrum intake. These results demonstrate that cVLP display has the potential to improve the systemic humoral responses elicited against low-immunogenic antigens in pigs; however, this effect is dependent on the use of antigens, which are not the targets of pre-existing maternal immunity.

N-3 Polyunsaturated Fatty Acids as a Nutritional Support of the Reproductive and Immune System of Cattle-A Review.

This paper focuses on the role of n-3 fatty acids as a nutrient crucial to the proper functioning of reproductive and immune systems in cattle. Emphasis was placed on the connection between maternal and offspring immunity. The summarized results confirm the importance and beneficial effect of n-3 family fatty acids on ruminant organisms. Meanwhile, dietary n-3 fatty acids supplementation, especially during the critical first week for dairy cows experiencing their peripartum period, in general, is expected to enhance reproductive performance, and the impact of its supplementation appears to be dependent on body condition scores of cows during the drying period, the severity of the negative energy balance, and the amount of fat in the basic feed ration. An unbalanced, insufficient, or excessive fatty acid supplementation of cows' diets in the early stages of pregnancy (during fetus development) may affect both the metabolic and nutritional programming of the offspring. The presence of the polyunsaturated fatty acids of the n-3 family in the calves' ration affects not only the performance of calves but also the immune response, antioxidant status, and overall metabolism of the future adult cow.

Assessing the Presence of IgG Antibodies against Influenza Viruses in Neonates after Maternal Vaccination and Factors That May Affect the Transplacental Transfer.

Special populations, particularly pregnant women, are uniquely susceptible to infectious diseases due to alterations in their immunological, respiratory, and cardiovascular systems during gestation. Influenza infections during the perinatal period have been associated with more severe maternal and perinatal outcomes, underscoring the critical importance of vaccination data for pregnant women. According to the World Health Organization (WHO), all pregnant women and those of childbearing age should receive the inactivated influenza vaccine, irrespective of their pregnancy stage. This study aimed to elucidate factors influencing neonatal antibody presence following maternal influenza vaccination. Conducted through convenience sampling in Athens, Greece, this study involved 78 pregnant women who received flu vaccinations. The participants completed questionnaires covering demographics, obstetric history, attitudes toward influenza vaccination, and knowledge about the influenza virus and pregnancy vaccination. Blood samples were collected from 83 neonates to assess IgG antibody presence. Five of the surveyed women had twin pregnancies. The statistical analysis employed IBM SPSS-Statistics version 26.0. This study revealed the presence of positive influenza A and B antibodies in neonates following maternal immunization. Furthermore, it identified factors such as the gestational week and timing of vaccination during pregnancy that influenced the transfer of antibodies from mother to fetus. These findings offer valuable insights for healthcare professionals to provide informed recommendations on influenza vaccination during pregnancy and empower expectant mothers to make informed decisions about the benefits of immunization.

Transfer of maternal immunity using a polyvalent vaccine and offspring protection in Nile tilapia, Oreochromis niloticus

Background Vaccination is an effective and alternative means of disease prevention, however, it cannot be conducted on the offspring of fish. For this process to take place, the transfer of maternal immunity should be implemented. This study aims to determine the effectiveness of transferring immunity from the broodstock to the offspring using a polyvalent vaccine against Aeromonas hydrophila, Streptococcus agalactiae, and Pseudomonas fluorescens in Nile tilapia, Oreochromis niloticus. Methods Nile tilapia broodstock with an average weight of 203g (±SD 23) was reared in spawning ponds until mass spawning and harvested one week post-spawning for vaccination. After being vaccinated according to the treatment, each fish broodstock was reared in 3x3 m cages installed in an earthen pond with a density of 20 broodstock, consisting of 15 females and 5 males. The vaccine used was a formalin-killed whole-cell vaccine at a density of 1010 cfu/mL injected intramuscularly (i.m.) at a dose of 0.4 mL/kg fish. Nile tilapia was injected with a vaccine used as a treatment. Example include A. hydrophila monovalent (MA), S. agalactiae monovalent (MS), P. fluorescens monovalent (MP), A. hydrophila and S. agalactiae bivalent (BAS), A. hydrophila and P. fluorescens bivalent (BAP), P. fluorescens and S. agalactiae bivalent (BPS), and A. hydrophila, S. agalactiae, and P. fluorescens polyvalent vaccines (PAPS). While the control was fish that were injected with a PBS solution. The broodstock’s immune response was observed on the 7th, 14th, 21st, and 28th days, while the immune response and challenge test on the offspring was conducted on the 10th, 20th, 30th, and 40th day during the post-hatching period. The parameters observed consisted of total leukocytes, phagocytic activity, antibody titer, lysozyme, and relative survival percentage (RPS). Result The application of PAPS in broodstock could significantly induce the best immune response and immunity to multiple diseases compared to other treatments. The RPS of the PAPS was also higher than the other types of vaccines. This showed that the transfer of immunity from the broodstock to the Nile tilapia offspring could protect it against bacterial diseases such as A. hydrophila, S. agalactiae, and P. fluorescens. Conclusion The application of polyvalent vaccine A. hydrophila, S. agalactiae, P. fluorescens vaccines increased the broodstock’s immune response and it was transferred to their offsprings. Polyvalent vaccines derived from maternal immunity can protect offspring from disease up to 30 days of age. They were able to produce tilapia seeds that are immune to diseases caused by A. hydrophila, S. agalactiae, and P. fluorescens.

Importance, indication and safety of maternal immunization

Vaccination is a very important spectrum for building immunity to fight certain infections. Doing vaccination on the mother as well as the baby, which safeguards both of them, is known as maternal immunization. After childbirth, babies are prone to get infected by many diseases as their immunity is inferior during that time. Over the years, numerous studies have shown that vaccinating mothers can effectively reduce the risk of illnesses such as smallpox, polio, etc. This vaccination process helps strengthen the body's system and enables it to combat these diseases effectively when necessary. This approach works by boosting the transfer of antibodies from the person to the fetus through the placenta, providing passive immunity to the infant during their initial months of life until they become eligible for their own vaccines. In addition to protecting infants, maternal immunization can also help prevent complications for individuals caused by infections that could impact their health and pregnancy outcomes. This review focuses on discussing the significance, indications, and safety of immunization for diseases that pose a high risk to both pregnant individuals and their infants.

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

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

Need for open data on COVID-19 vaccine uptake among pregnant people in the Caribbean: a call to action.

Pregnant people with coronavirus disease 2019 (COVID-19) have a higher risk of adverse maternal and fetal outcomes compared with pregnant people without COVID-19. In 2021, large increases in maternal mortality were reported in Jamaica, almost half of which were attributable to COVID-19. COVID-19 vaccination has been shown to reduce these risks, but low- and middle-income countries lack free, publicly available data, known as open data, on COVID-19 vaccine uptake for their pregnant populations. The objectives of this paper were to: review how high-income countries use open data to detect trends in COVID-19 vaccine uptake among pregnant people and develop vaccination distribution strategies; outline barriers to making open data available for maternal COVID-19 vaccination in the Caribbean; and propose a multipronged strategy that would increase the availability of open data on maternal COVID-19 vaccination in the Caribbean. A multipronged strategy to fill the data void would involve: (i) utilizing existing Caribbean maternal immunization data collection entities; (ii) adapting digital software tools to establish maternal electronic immunization registries; and (iii) collaborating with local partners skilled in data analytics. Making open data available for COVID-19 vaccine uptake among pregnant people in the Caribbean could offer substantial benefits, including the development of measurable maternal COVID-19 vaccination goals and the facilitation of vaccine decision-making discussions between providers and pregnant people.

Fetal Maternal Hemorrhage As a Trigger for Fetal/Neonatal Alloimmune Thrombocytopenia: Evidence from a Murine Model

Fetal/neonatal alloimmune thrombocytopenia (FNAIT) is a severe bleeding disorder caused by maternal alloantibodies targeting fetal platelet alloantigens. Among the 37 human platelet alloantigens (HPAs) identified, the HPA-1a/HPA-1b polymorphism, involving a Leu33Pro amino acid substitution in the integrin β3 subunit, is the most common cause of severe FNAIT, particularly in Caucasians. Leu33 serves as a key target for alloantibody binding, leading to fetal and neonatal thrombocytopenia and, in severe cases, spontaneous or trauma-induced intracranial hemorrhage. FNAIT shares a pathophysiologic basis with Hemolytic Disease of the Fetus and Newborn (HDFN), which stem from maternal immunization to alloantigens on fetal platelets and red blood cells (RBCs), respectively. While alloimmunization against RBC alloantigens typically occurs in response to fetal maternal hemorrhage (FMH), a clear link between FMH and maternal alloimmunization against HPA-1a on circulating fetal platelets has remained elusive. To assess whether FMH can induce platelet alloimmunization and lead to the development of FNAIT during pregnancy, we utilized recently developed transgenic mice expressing the HPA-1a allogeneic epitope on a murine GPIIIa backbone. To simulate varying degrees of FMH, we transfused different doses of HPA-1a platelets into wild-type (WT), non-pregnant female mice. We found that transfusing as few as 1x10 7 HPA-1a-positive platelets (equivalent to a FMH of approximately 30 ml in humans) resulted in production of high-titer HPA-1a-specific alloantibodies. Since >25% of the cases of FNAIT in humans are thought to occur in what are experienced as first pregnancies, we further investigated whether exposure to HPA-1a in pregnant female mice could still induce FNAIT. We found that when WT female mice pregnant with HPA-1a-positive fetuses were transfused with HPA-1a-positive platelets, they consistently developed HPA-1a-specific antibodies with similar titers as observed in non-pregnant females and delivered thrombocytopenic pups with FNAIT. Taken together, these findings demonstrate that exposure to HPA-1a-positive platelets in the maternal circulation during pregnancy is sufficient to trigger FNAIT, and that maternal tolerance, normally increased during pregnancy, does not play a significantly immunosuppressive role to prevent alloimmunization to the HPA-1a epitope. These findings support the notion that FMH may be a possible cause of alloimmunization in humans, even during a first pregnancy. Finally, the result of this study further validates the usefulness of this HPA-1a alloantigen-specific humanized transgenic mouse model to explore the etiology and pathophysiology of FNAIT. Further studies should significantly advance preventative and therapeutic strategies for this life-threatening immunologic disorder.