Maternal Immunization Research Articles

Capability and feasibility of the Global Alignment of Immunisation Safety Assessment in pregnancy criteria for the assessment of pregnancy and birth outcomes in Kinshasa, Democratic Republic of the Congo: a prospective cohort study

IntroductionThere is an urgent need to investigate the capabilities of active surveillance in strengthening the development of pharmacovigilance (PV) systems in low-resource settings. Here, we assess the capability and feasibility...

Maternal Perception, Hesitancy, and Satisfaction Toward Childhood Immunization in Primary Health Centers, Hafr Al-Batin: A Multicenter Cross-Sectional Study from Eastern Saudi Arabia.

Consumer perception of and satisfaction with vaccination services is a critical and commonly used indicator for evaluating the quality of services provided by concerned authorities. The present survey assessed maternal perceptions, hesitancy, satisfaction, and factors associated with childhood immunization services provided at the primary health centers (PHCs) of eastern Saudi Arabia. The current analytical cross-sectional study included mothers of childhood vaccine beneficiaries attending PHCs in Hafr Al-Batin. We collected data related to mothers' perceptions, hesitancy, and satisfaction using a validated Arabic version of the data collection tool. Factors associated with low and high satisfaction with the immunization services were evaluated using logistic regression analysis. We performed Spearman correlation test to identify the correlation between the perception and satisfaction scores. Of the 675 participants, 87.4% were satisfied with the immunization services provided at the PHCs. The participants' satisfaction was significantly associated with the immunized child's age group (adjusted odds ratio [AOR] = 1.89, 95% CI = 1.39-2.89, p = 0.037) and occupation status (AOR = 1.42, 95% CI = 1.17-1.74, p = 0.024). Vaccine hesitancy was significantly associated with the mother's age group (AOR = 1.89, 95% CI of AR = 1.35-3.39, P = 0.003) and number of children (AOR = 1.42, 95% CI of AR = 1.17-1.74, P = 0.024), Additionally, we found a significant positive correlation (Spearman's rho = 0.207, p < 0.001) between perception and satisfaction scores. We recommend targeted health education programs for mothers to improve their perceptions and the importance of all recommended childhood vaccines. Additionally, we suggest continuing maternal satisfaction assessments to enhance and maintain the quality of vaccination services.

Exacerbated Zika virus-induced neuropathology and microcephaly in fetuses of dengue-immune nonhuman primates.

Zika virus (ZIKV) is a mosquito-borne flavivirus that can vertically transmit from mother to fetus, potentially causing congenital defects, including microcephaly. It is not fully understood why some fetuses experience severe complications after in utero exposure to ZIKV, whereas others do not. Given the antigenic similarity between ZIKV and the closely related virus dengue (DENV) and the potential of DENV-specific antibodies to enhance ZIKV disease severity in mice, we questioned whether maternal DENV immunity could influence fetal outcomes in a nonhuman primate model of ZIKV vertical transmission. We found significantly increased severity of congenital Zika syndrome (CZS) in fetuses of DENV-immune cynomolgus macaques infected with ZIKV in early pregnancy compared with naïve controls, which occurred despite no effect on maternal ZIKV infection or antibody responses. Ultrasound measurements of head circumference and biparietal diameter measurements taken sequentially throughout pregnancy demonstrated CZS in fetuses of DENV-immune pregnant macaques. Furthermore, severe CZS enhanced by DENV immunity was typified by reduced cortical thickness and increased frequency of neuronal death, hemorrhaging, cellular infiltrations, calcifications, and lissencephaly in fetal brains. This study shows that maternal immunity to DENV can worsen ZIKV neurological outcomes in fetal primates, and it provides an animal model of vertical transmission closely approximating human developmental timelines that could be used to investigate severe ZIKV disease outcomes and interventions in fetuses.

Immunogenetics of Schizophrenia in the Light of Modern Genome-Wide Association Studies

Background: Immunological and genetic studies of schizophrenia form two areas of biological psychiatry in which significant progress has been made in recent years related to understanding the role of both neuroinflammation and genetic vulnerability in the development of this disease. However, data to explain the complicity of these two factors in the etiology and pathogenesis of schizophrenia are still insufficient. The aim of the review is to assess the degree of interaction between genetic predisposition and neuroinflammation in the pathogenetic mechanisms of schizophrenia based on the currently available information on genes associated with the immune system according to genome-wide association analysis (GWAS), as well as models that involve the interaction of immunological and genetic factors, including taking into account environmental adversities. Material and method: using keywords “genome-wide association study, Mendelian randomization, regulatory regions, maternal immunity activation, synaptic pruning, microglia” both in international and domestic databases the scientific publications selected. Conclusions: recent studies have identified genomic regions that contain genes involved in the functioning of the immune system. Particular attention is paid to the MHC region, and one of the most important achievements in its study is the establishment of the role of the complement gene (component C4A) in the formation of synapses and their abnormal elimination. Other genes, both inside and outside the major histocompatibility complex (MHC) region, are of interest, and their functions in the brain and their involvement in the pathogenesis of schizophrenia have yet to be elucidated. The establishment of causal relationships between GWAS data for schizophrenia and immunological indicators of inflammation using the Mendelian randomization (MR method) indicates that the increase in the level of pro-inflammatory cytokines in patients with schizophrenia is an intrinsic symptom of the disease, and is not a consequence of the course of the pathological process. Adverse environmental factors play an important role in the interaction of genetic variants associated with schizophrenia and microglial activation, which leads to synaptic disorders.

Relationship of maternal cytomegalovirus-specific antibody responses and viral load to vertical transmission risk following primary maternal infection in a rhesus macaque model.

Cytomegalovirus (CMV) is the most common congenital infection and cause of birth defects worldwide. Primary CMV infection during pregnancy leads to a higher frequency of congenital CMV (cCMV) than maternal re-infection, suggesting that maternal immunity confers partial protection. However, poorly understood immune correlates of protection against placental transmission contributes to the current lack of an approved vaccine to prevent cCMV. In this study, we characterized the kinetics of maternal plasma rhesus CMV (RhCMV) viral load (VL) and RhCMV-specific antibody binding and functional responses in a group of 12 immunocompetent dams with acute, primary RhCMV infection. We defined cCMV transmission as RhCMV detection in amniotic fluid (AF) by qPCR. We then leveraged a large group of past and current primary RhCMV infection studies in late-first/early-second trimester RhCMV-seronegative rhesus macaque dams, including immunocompetent (n = 15), CD4+ T cell-depleted with (n = 6) and without (n = 6) RhCMV-specific polyclonal IgG infusion before infection to evaluate differences between RhCMV AF-positive and AF-negative dams. During the first 3 weeks after infection, the magnitude of RhCMV VL in maternal plasma was higher in AF-positive dams in the combined cohort, while RhCMV glycoprotein B (gB)- and pentamer-specific binding IgG responses were lower magnitude compared to AF-negative dams. However, these observed differences were driven by the CD4+ T cell-depleted dams, as there were no differences in plasma VL or antibody responses between immunocompetent AF-positive vs AF-negative dams. Overall, these results suggest that levels of neither maternal plasma viremia nor humoral responses are associated with cCMV following primary maternal infection in healthy individuals. We speculate that other factors related to innate immunity are more important in this context as antibody responses to acute infection likely develop too late to influence vertical transmission. Yet, pre-existing CMV glycoprotein-specific and neutralizing IgG may provide protection against cCMV following primary maternal CMV infection even in high-risk, immunocompromised settings.

Respiratory Syncytial Virus Prefusion F Subunit Vaccine: First Approval of a Maternal Vaccine to Protect Infants.

Pfizer is developing a bivalent respiratory syncytial virus (RSV) prefusion F subunit vaccine (RSVpreF; ABRYSVO™) for preventing RSV illness in infants and individuals aged ≥ 60 years. RSVpreF received approval for vaccination of pregnant individuals to help protect infants against RSV illness on 21 August 2023 in the USA. RSVpreF is also approved in the USA (31 May 2023) for active immunization of individuals aged ≥ 60 years for the prevention of lower respiratory tract disease (LRTD) caused by RSV. In the EU, RSVpreF has received approval for both indications, and it has been submitted for regulatory approval in Canada (both indications) and in Japan (maternal immunization to protect infants). This article summarizes the milestones in the development of RSVpreF leading to the approval for use in pregnant individuals to prevent LRTD in infants.

Seroprevalence of Respiratory Syncytial Virus among Rural Population: Insights into Infection Rates and Immune Status: Pilot Study

Respiratory Syncytial Virus (RSV) is a significant cause of respiratory tract infections, particularly affecting infants, young children, and immunocompromised individuals, with a substantial global burden of morbidity and mortality. This study aimed to assess the seroprevalence of RSV among a rural population in Karad Taluka, India, an area where RSV data is scarce due to its predominantly urban focus. Ethical approval was obtained, and written informed consent was collected from participants' parents or legal guardians Blood samples were collected from individuals aged 16 months to 5 years residing in rural areas, and IgM RSV-specific antibodies were detected to identify recent infections using SERION enzyme-linked immunosorbent assay (ELISA). Additionally, demographic information and clinical history were collected through a structured questionnaire. The data were entered into an electronic database, and seroprevalence was calculated based on the proportion of individuals with positive serological results. The study revealed that by the age of 3 years, 81.0% of children exhibited IgM seropositivity to RSV, with a cumulative seroprevalence of 72% in the entire study population. The seroprevalence varied with age, demonstrating an ongoing RSV activity within the community, as evidenced by the high IgM positivity. However, as children grew older, a decline in IgM positivity was observed, possibly due to protective antibodies developed from previous exposures or a longer time elapsed between RSV exposure and sample collection in older children. These findings underscore the vulnerability of young infants to RSV and the need for early protection in India. It highlights the importance of considering timing and age-appropriate administration of RSV vaccines in vaccination strategies, as well as the potential limitations of maternal immunization in protecting preterm infants. Understanding RSV seroprevalence in rural areas is crucial for guiding public health interventions and resource allocation to mitigate the impact of this virus on vulnerable populations, particularly young children who are at the highest risk.

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

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

Assessment of Peste des Petits Ruminants Antibodies in Vaccinated Pregnant Ewes of Kazakh Breed Fine-Fleeced and Determination of the Decreasing Trend of Maternal Immunity in Their Lambs.

In this article, we first assessed peste des petits ruminants (PPR) antibodies in vaccinated pregnant ewes of Kazakh breed fine-fleeced immunized with the PPR vaccine and the duration of maternal immunity in their lambs. Ewes in the last trimester of pregnancy and gestation were immunized with a vaccine from the Nigeria 75/1 strain of the PPR virus (PPRV) produced by the Research Institute of Biological Safety Problems (RIBSP), Kazakhstan. Serum samples from lambs born from vaccinated and unvaccinated ewes were collected a week after birth and at intervals of 7 days for 18 weeks after birth. Serum samples collected from lambs were tested for PPR antibodies using competitive ELISA and virus neutralization test (VNT). Maternal antibodies (MAs) in lambs born from vaccinated ewes were detected for up to 18 weeks, with a tendency to decrease starting at week 14, and by the end of the experiment receded below the protective level (<1:8). In the blood serum of a 14-week-old lamb with MAs (1:8), post vaccination with a field dose (103 TCID50) of the vaccine against PPR, the titers of protective antibodies against PPRV increased to 1:16 on day 14 post vaccination, and the lamb was protected from infection with the field PPRV. A lamb of the same age with MAs in the 1:8 titer was 100% protected from infection with the field PPRV. Therefore, it is recommended that lambs of the Kazakh fine-wool breed be immunized from the age of 14 weeks or older to avoid a period of susceptibility.

Protective effect of pre-existing natural immunity in a nonhuman primate reinfection model of congenital cytomegalovirus infection.

Congenital cytomegalovirus (cCMV) is the leading infectious cause of neurologic defects in newborns with particularly severe sequelae in the setting of primary CMV infection in the first trimester of pregnancy. The majority of cCMV cases worldwide occur after non-primary infection in CMV-seropositive women; yet the extent to which pre-existing natural CMV-specific immunity protects against CMV reinfection or reactivation during pregnancy remains ill-defined. We previously reported on a novel nonhuman primate model of cCMV in rhesus macaques where 100% placental transmission and 83% fetal loss were seen in CD4+ T lymphocyte-depleted rhesus CMV (RhCMV)-seronegative dams after primary RhCMV infection. To investigate the protective effect of preconception maternal immunity, we performed reinfection studies in CD4+ T lymphocyte-depleted RhCMV-seropositive dams inoculated in late first / early second trimester gestation with RhCMV strains 180.92 (n = 2), or RhCMV UCD52 and FL-RhCMVΔRh13.1/SIVgag, a wild-type-like RhCMV clone with SIVgag inserted as an immunological marker, administered separately (n = 3). An early transient increase in circulating monocytes followed by boosting of the pre-existing RhCMV-specific CD8+ T lymphocyte and antibody response was observed in the reinfected dams but not in control CD4+ T lymphocyte-depleted dams. Emergence of SIV Gag-specific CD8+ T lymphocyte responses in macaques inoculated with the FL-RhCMVΔRh13.1/SIVgag virus confirmed reinfection. Placental transmission was detected in only one of five reinfected dams and there were no adverse fetal sequelae. Viral whole genome, short-read, deep sequencing analysis confirmed transmission of both reinfection RhCMV strains across the placenta with ~30% corresponding to FL-RhCMVΔRh13.1/SIVgag and ~70% to RhCMV UCD52, consistent with the mixed human CMV infections reported in infants with cCMV. Our data showing reduced placental transmission and absence of fetal loss after non-primary as opposed to primary infection in CD4+ T lymphocyte-depleted dams indicates that preconception maternal CMV-specific CD8+ T lymphocyte and/or humoral immunity can protect against cCMV infection.

Factors affecting the choice of vaccination during pregnancy

Maternal immunization has been reviewed and proven to be quite beneficial in reducing sickness in pregnant women and neonates, Nevertheless, such programs have had limited uptake in some countries. Despite the numerous advantages that vaccines bring to humanity, people may harbor anti-vaccine beliefs for a variety of reasons, including a lack of knowledge about vaccines, worry, and fear. The purpose of this literature review was to determine the spectrum of concerns, trust, and access difficulties that influence the choice of vaccination during pregnancy.

Influence of maternal factors on the immunization status of under- five in Ebonyi state

Background: Poor delivery of childhood immunization with the interacting factors has been a significant public health challenge especially in the sub-Saharan Africa. Nigeria has been presented as one the countries with the worst under-five mortality rates, and factors affecting childhood immunization including maternal factors are poorly understood. The study determined the influence of maternal characteristics and immunization status of under-five children in Ebonyi State. Methods: Data were collected using an Immunization Status Checklist (ISC). The population of the study was 572,955 under-five children in Ebonyi State from which 2865 was sampled. Data were analyzed using percentages and chi-square. Results: The findings of the study revealed that 83.01% of under-5 children were fully immunized. The chi-square analysis shows a significant influence of mothers’ parity at (p&lt;0.05), mothers’ occupation at (p&lt;0.05) and mothers’ use of antenatal services at (p&lt;0.05). Conclusions: The study concluded that immunization status of under-five children in Ebonyi State was high and maternal characteristics had significant influence on immunization status of under-five children. Thus, recommended that government should provide tangible incentives to mothers who fully immunized their children and promulgate a law to prevent children without immunization cards showing full immunization from registering in public and private primary schools.

Maternal acellular pertussis vaccination in mice impairs cellular immunity to Bordetella pertussis infection in offspring.

Given the resurgence of pertussis, several countries have introduced maternal tetanus, diphtheria, and acellular pertussis (aP) vaccination during pregnancy to protect young infants against severe pertussis. Although protective against the disease, the effect of maternal aP vaccination on bacterial colonization of the offspring is unknown. Here, we used a mouse model to demonstrate that maternal aP immunization, either before or during pregnancy, protects pups from lung colonization by Bordetella pertussis. However, maternal aP vaccination resulted in significantly prolonged nasal carriage of B. pertussis by inhibiting the natural recruitment of IL-17-producing resident memory T cells and ensuing neutrophil influx in the nasal tissue, especially of those with proinflammatory and cytotoxic properties. Prolonged nasal carriage after aP vaccination is due to IL-4 signaling, as prolonged nasal carriage is abolished in IL-4Rα-/- mice. The effect of maternal aP vaccination can be transferred transplacentally to the offspring or via breastfeeding and is long-lasting, as it persists into adulthood. Maternal aP vaccination may, thus, augment the B. pertussis reservoir.

A GIS-based approach to identifying communities underserved by primary health care services-An Afghanistan case study.

Afghanistan has been in an active state of conflict and war for twenty continuous years. Social services like health and education have been badly affected, facing issues such as service disruption, brain drain, and generalized instability. Health indices that provide proxy indicators for general population wellness, such as maternal health, child mortality, and immunization coverage, show that the health services available to the Afghan population are sub-optimal. Investment in social service and interventions has increased. The World Bank and the United Nations through its agencies (The World Health Organization (WHO) and United Nations' Children's Fund (UNICEF) are providing social support through targeted and strategic programs. However, the topographic and environmental realities of Afghanistan, with its broad mountain coverage, propensity toward natural disasters, and latent conflict, has made data and information gathering arduous. Since data is essential for measurement and management, the WHO Health Emergencies (WHE) information management unit at WHO Afghanistan has delivered an innovative form of data analysis, specialized and targeted at providing improved information on communities that are not adequately covered by health services. Deploying a geographical information system (GIS) approach, the WHE team has collated primary and secondary data from a combination of datasets to produce a far-reaching piece of analysis. The analysis of underserved communities in hard to reach, remote locations, provides a live, evidence-based information product. This provides a working tool that is essential to primary health programming and intervention in Afghanistan. The estimates show that approximately 9.5 million individuals in 22,181 villages across 34 provinces are underserved by primary health services. This paper is presented to explain the underpinning methodology.

Hepatitis E Virus (HEV) in Heavy Pigs in Slaughterhouses of Northern Italy: Investigation of Seroprevalence, Viraemia, and Faecal Shedding.

Hepatitis E virus (HEV) is considered an emerging threat in Europe, owing to the increased number of human cases and the widespread presence of the virus in pigs at farms. Most cases in industrialized countries are caused by the zoonotic HEV-3 genotype. The main transmission route of HEV-3 in Europe is foodborne, through consumption of raw or undercooked liver pork and wild boar meat. Pigs become susceptible to HEV infection after the loss of maternal immunity, and the majority of adult pigs test positive for IgG anti-HEV antibodies. Nonetheless, HEV-infected pigs in terms of liver, faeces, and rarely blood are identified at slaughterhouses. The present study aimed to investigate the prevalence of HEV-positive batches of Italian heavy pigs at slaughterhouses, assessing the presence of animals still shedding HEV upon their arrival at the slaughterhouse by sampling faeces collected from the floor of the trucks used for their transport. The occurrence of viraemic animals and the seroprevalence of anti-HEV antibodies were also assessed. The results obtained indicated the presence of anti-HEV IgM (1.9%), and a high seroprevalence of anti-HEV total antibodies (IgG, IgM, IgA; 89.2%, n = 260). HEV RNA was not detected in either plasma or faecal samples. Nevertheless, seropositive animals were identified in all eight batches investigated, confirming the widespread exposure of pigs to HEV at both individual and farm levels. Future studies are needed to assess the factors associated with the risk of HEV presence on farms, with the aim to prevent virus introduction and spread within farms, thereby eliminating the risk at slaughterhouse.

Active inoculation with an inactivated Coxsackievirus A2 vaccine induces neutralizing antibodies and protects mice against lethal infection

Coxsackievirus A2 (CVA2) is one of the causative agents of hand-foot-and-mouth disease (HFMD), which poses a great challenge for global public health. However, presently, there are no available commercial vaccines or antivirals to prevent CVA2 infection. Here, we present an inactivated Vero cell-based whole CVA2 vaccine candidate and evaluate its safety and efficacy in this study. Neonatal BALB/c mice were vaccinated at 5 and 7 days old, respectively, and then challenged with either homologous or heterologous strain of CVA2 at a lethal dose at 10 days old. The inactivated whole CVA2 vaccine candidate showed a high protective efficacy. Additionally, our inactivated vaccine stimulated the production of CVA2-specific IgG1 and IgG2a antibodies in vivo and high titers of neutralization antibodies (NtAbs) in the serum of immunized mice. Maternal immunization with the inactivated CVA2 vaccine provided full protection to pups against lethal infection. Compared with mice inoculated with only alum, the viral loads were decreased, and pathological changes were relieved in tissue samples of immunized mice. Moreover, the transcription levels of some genes related to cytokines (IFN-γ and TNF-α, MCP-1, IL-6, CXCL-10 etc.) were significantly reduced. The number of immune cells and levels of cytokines in peripheral blood of mice inoculated with only alum were higher than that of immunized mice. It is noteworthy that this vaccine showed a good cross-immunity efficacy against Enterovirus A71 (EVA71) challenge. In conclusion, our findings suggest that this experimental inactivated CVA2 vaccine is a promising component of polyvalent vaccines related to HFMD in the near future.

Vaccine hesitancy and knowledge regarding maternal immunization among reproductive age women in central Italy: a cross sectional study.

Vaccination in pregnancy offers protection to the mother and the newborn. In Italy, influenza, pertussis, and COVID-19 vaccinations are recommended in pregnancy, but vaccination coverage is still far from the National Immunization Plan goals. We aimed to assess knowledge and attitude on maternal immunization in two groups of Italian women, in pregnancy and in reproductive age (non pregnant). A cross sectional study on Italian childbearing age women gathering information on their knowledge on maternal immunization and attitudes to receiving influenza and pertussis vaccines in pregnancy was carried out at the University of Rome Tor Vergata, between September 2019 and February 2020. Logistic and multinomial regressions were chosen as statistical tests for our analysis. 1,031 women participated in the survey by answering the questionnaire. Out of these, 553 (53.6%) women were pregnant, and 478 (46.4%) were in the reproductive age. 37% (204/553) of pregnant women and 41% (198/476) of non pregnant women are aware of the existence of an immunization plan for pregnant women in Italy. The group with age between 20 and 30, for both pregnant women and women in the reproductive age, has a better knowledge of vaccination in pregnancy. Working status is a variable associated with more awareness about vaccination during pregnancy only for pregnant women (OR = 2.34, p < 0.00001). Educational status, trimester of pregnancy and knowledge on the topic are associated with vaccine hesitancy in our multivariate analysis for pregnant women. In the reproductive age group women who had a previous pregnancy are more likely to be hesitant towards vaccination in pregnancy, on the other hand the one with a higher knowledge and educational status are more likely to get vaccinated. The study highlights the persistent vaccine hesitancy among Italian women of reproductive age and pregnant women. Despite healthcare providers being identified as a reliable source of information, their recommendations alone are insufficient to overcome vaccine hesitancy. Factors such as employment status, educational level, pregnancy trimester, and knowledge about vaccinations during pregnancy influence vaccine hesitancy. Tailored educational interventions and communication campaigns targeting these areas can help reduce vaccine hesitancy and promote maternal immunization.

Examining spatial variation for immunisation coverage in pregnant women: A nationwide and geospatial retrospective cohort study in Aotearoa New Zealand

BackgroundMaternal influenza and pertussis immunisation is crucial for protecting mothers during pregnancy and their babies in the first weeks of life against severe disease. We examined geospatial variation in maternal immunisation coverage among pregnant women in Aotearoa New Zealand and its health equity implications. MethodWe constructed a retrospective cohort including all pregnant women who delivered between 01 January 2013 and 31 December 2020 using administrative health datasets. Our outcomes were receipt of influenza or pertussis vaccine in any one of three relevant national databases (e.g. National Immunisation Register, Proclaims, or Pharmaceutical collection) during the eligible pregnancy. ResultsData from our retrospective cohort study show significant regional variation in maternal immunisation coverage for both influenza and pertussis from 2013 to 2020. Maximal coverage was around 50% in the best performing regions, which means that half of the women who were pregnant (183,737 women) were not protected. In addition, we found significant spatio-temporal variation and clustering of immunisation coverage. Our findings are interactively available to explore here: https://geohealthlab.shinyapps.io/hapumama/ ConclusionOur study is one of the first to examine spatial variation in maternal vaccination coverage in pregnant women at a national level over space and time. This provides powerful tools to measure the impact of interventions to improve coverage at national and regional levels, with specific reference to inequities between ethnic groups, likely applicable to similar settings internationally.

Reduced maternal immunity and vertical transfer of immunity against SARS-CoV-2 variants of concern with COVID-19 exposure or initial vaccination in pregnancy.

As the SARS-CoV-2 pandemic continues to evolve, we face new variants of concern with a concurrent decline in vaccine booster uptake. We aimed to evaluate the difference in immunity gained from the original SARS-CoV-2 mRNA vaccine series in pregnancy versus SARS-CoV-2 exposure during pregnancy against recent variants of concern. This is a retrospective analysis of previously collected samples from 192 patients who delivered between February 2021 and August 2021. Participants were categorized as 1) COVID vaccine: mRNA vaccine in pregnancy, 2) COVID-exposed, and 3) controls. The primary outcome was neutralizing capacity against wild-type, Delta, and Omicron-B1 between cohorts. Secondary outcomes include a comparison of cord-blood ID50 as well as the efficiency of vertical transfer, measured by cord-blood:maternal blood ID50 for each variant. Pregnant women with COVID-19 vaccination had a greater spike in IgG titers compared to both those with COVID-19 disease exposure and controls. Both COVID exposure and vaccination resulted in immunity against Delta, but only COVID vaccination resulted in significantly greater Omicron ID-50 versus controls. The neutralizing capacity of serum from newborns was lower than that of their mothers, with COVID-vaccination demonstrating higher cord-blood ID50 vs wildtype and Delta variants compared to control or COVID-exposed, but neither COVID-exposure nor vaccination demonstrated significantly higher Omicron ID50 in cord-blood compared to controls. There was a 0.20 (0.07-0.33, p=0.004) and 0.12 (0.0-0.24, p=0.05) increase in cord-blood:maternal blood ID50 with COVID vaccination compared to COVID-19 exposure for wild-type and Delta respectively. In pair-wise comparison, vertical transfer of neutralization capacity (cord-blood:maternal blood ID50) was greatest for wild-type and progressively reduced for Delta and Omicron ID50. Pregnant patients with either an initial mRNA vaccination series or COVID-exposure demonstrated reduced immunity against newer variants compared to wild-type as has been reported for non-pregnant individuals; however, the COVID-vaccination series afforded greater cross-variant immunity to pregnant women, specifically against Omicron, than COVID-disease. Vertical transfer of immunity is greater in those with COVID vaccination vs COVID disease exposure but is reduced with progressive variants. Our results reinforce the importance of bivalent booster vaccination in pregnancy for both maternal and infant protection and also provide a rationale for receiving updated vaccines as they become available.

Vaccination effects on reducing COVID-19 complications in pregnancy: A large-scale report from Iran.

The objective of this study was to evaluate the effects of maternal coronavirus disease 2019 (COVID-19) vaccination on preventing severe complications of COVID-19 in pregnant women. A retrospective study was conducted in pregnant women infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) during pregnancy and/or for up to 6 weeks postpartum between September 1, 2021, to January 30, 2022. The data was retrieved from a national database. The pregnant women were divided into two groups of vaccinated and unvaccinated. The proposed outcomes (the need for hospitalization, intensive care unit admission, and mechanical ventilation and products of conception complications) were compared between the two groups. Approximately 90 000 pregnant women infected with COVID-19 were included in the study. The data of the vaccinated (19 922) and unvaccinated (70 147) groups were analyzed and compared. Pregnant patients in the vaccinated group had a significantly lower rate of hospitalization (21.2% vs 29.4%) (odds ratio [OR], 0.648 [95% confidence interval (CI), 0.625-0.673], P = 0.0001) and intensive care unit admission (3.7% vs 7.8%) (OR, 0.453 [95% CI, 0.382-0.535], P = 0.0001). The need for mechanical ventilation was also lower, although not statistically significant, in the vaccinated group than in the unvaccinated group (30 of 155 [19.4%] vs 418 of 1597 [26.2%]) (OR, 0.677 [95% CI, 0.448-1.024], P = 0.063). Cesarean section (54.3% vs 58.1%) (OR, 0.856 [95% CI, 0.751-0.977], P = 0.021) and stillbirth (0.4% vs 3.6%) (OR, 0.097 [95% CI, 0.026-0.252], P = 0.0001) were also significantly lower in the vaccinated patients. Most pregnant women in the vaccinated group (18 484-96.14%) received Sinopharm BIBP COVID-19 inactivated vaccine. No significant differences were seen in the effect of different types of COVID-19 vaccines on reducing COVID-19 complications in infected pregnant patients. Maternal COVID-19 immunization is effective in reducing COVID-19 complications in infected pregnant women.