Immunization During Pregnancy: Impact on the Infant

Maternal exposure to rubella infection elevates risk of congenital rubella syndrome (CRS)

The rise in neurodevelopmental disorders linked to maternal viral infections, particularly during the first and second trimesters of pregnancy, is concerning. Rubella, a contagious viral disease, primarily affects children and young adults, presenting as a rash and mild fever. It can also cause symptoms such as a swollen spleen, blueberry muffin skin spots, small head circumference, meningoencephalitis, developmental delays, and jaundice. When contracted in the first trimester, rubella can lead to severe birth defects or fetal death, with the risk declining after 20 weeks. Congenital rubella syndrome (CRS) caused by rubella's teratogenic effects, remains a major public health challenge, with an estimated 100,000 CRS cases annually. Following the approval of the rubella vaccine in 1969, significant strides have been made to reduce CRS and rubella incidences. This chapter provides disease management, prevention strategies, treatment options, and immunological response, focusing on prognosis and insights from current research on rubella and CRS.

Multilevel and subnational analysis of the predictors of maternity continuum of care completion in Nigeria: a cross-sectional survey

Understanding population discrepancy in maternity continuum of care (CoC) completion, particularly in sub-Saharan Africa is significant for interventional plan to achieve optimal pregnancy outcome and child survival. This study thus investigated the magnitudes, distribution, and drivers of maternity CoC completion in Nigeria. A secondary analysis of 19,474 reproductive age (15-49 years) women with at least a birth (level 1) in 1400 communities (level 2) across 37 states covered in the 2018 cross-sectional survey. Stepwise regression initially identified important variables at 10% cutoff point. Multilevel analysis was performed to determine the likelihood and significance of individual and community factors. Intra-cluster correlation assessed the degree of clustering and deviance statistics identified the optimal model. Only 6.5% of the women completed the CoC. Completion rate is significantly different between communities "4.3% in urban and 2.2% in rural" (χ2 = 392.42, p < 0.001) and was higher in southern subnational than the north. Education (AOR = 1.61, 95% CI 1.20-2.16), wealth (AOR = 1.73, 95% CI 1.35-2.46), media exposure (AOR = 1.22, 95% CI 1.06-1.40), women deciding own health (AOR = 1.37, 95% CI 1.13-1.66), taking iron drug (AOR = 1.84, 95% CI 1.43-2.35) and at least 2 dose of tetanus-toxoid vaccine during pregnancy (AOR = 1.35, 95% CI 1.02-1.78) are associated individual factors. Rural residency (AOR = 1.84, 95% CI = 1.43-2.35), region (AOR = 1.84, 95% CI 1.43-2.35) and rural population proportion (AOR = 1.84, 95% CI 1.43-2.35) are community predictors of the CoC completion. About 63.2% of the total variation in CoC completion was explained by the community predictors. Magnitude of maternity CoC completion is generally low and below the recommended level in Nigeria. Completion rate in urban is twice rural and more likely in the southern than northern subnational. Women residence and region are harmful and beneficial community drivers respectively. Strengthening women health autonomy, sensitization, and education programs particularly in the rural north are essential to curtail the community disparity and optimize maternity CoC practice.

Spatial behavior of hepatitis A, MMR, and varicella vaccination coverage in the state of Minas Gerais, 2020

OBJECTIVE

To analyze the spatial behavior of hepatitis A, measles, mumps, and rubella (MMR), and varicella vaccination coverage in children and its relationship with socioeconomic determinants in the state of Minas Gerais.

METHODS

This ecological study investigated records of doses administered to children, extracted from the Immunization Information System of 853 municipalities in Minas Gerais, in 2020. We analyzed the vaccination coverage and socioeconomic factors. Spatial scan statistics were used to identify spatial clusters and measure the relative risk based on the vaccination coverage indicator and the Bivariate Moran Index, and thus detect socioeconomic factors correlated with the spatial distribution of vaccination. We used the cartographic base of the state and its municipalities and the ArcGIS and SPSS software programs.

RESULTS

Hepatitis A (89.0%), MMR (75.7%), and varicella (89.0%) showed low vaccination coverage. All vaccines analyzed had significant clusters. The clusters most likely to vaccinate their population were mainly located in the Central, Midwest, South Central, and Northwest regions, while the least likely were in the North, Northeast, and Triângulo do Sul regions. The municipal human development index, urbanization rate, and gross domestic product were spatially dependent on vaccination coverage.

CONCLUSIONS

The spatial behavior of hepatitis A, MMR, and varicella vaccination coverage is heterogeneous and associated with socioeconomic factors. We emphasize that vaccination records require attention and should be continuously monitored to improve the quality of information used in services and research.

Seroprevalence Study of Pertussis in Adults at Childbearing Age and Young Infants Reveals the Necessity of Booster Immunizations in Adults in China

In China, the vaccination strategy against pertussis is started from 3 months of age, with no booster dose used after the booster given at two years. Despite a high vaccination coverage, pertussis has been increasingly reported since the last decade. This study evaluates the prevalence of serum anti-pertussis toxin (PT) IgG antibodies in adults at childbearing age and infants before the age of primary immunization in Beijing, China. A total of 1175 serum samples randomly selected from individuals who attended an annual health examination at the Sixth Medical Center of the PLA General Hospital, Beijing, in 2019, was included. The geometric mean concentration (GMC) and median concentration of anti-PT IgG antibodies among adults aged 20–39 years were 3.81 IU/mL and 3.24 IU/mL, and the corresponding concentrations were 1.72 IU/mL and 1.43 IU/mL among infants under 3 months of age. The seroprevalence of PT IgG antibodies ≥ 40 IU/mL in adults and infants was 2.0% (15/735) and 1.1% (5/440). In total, 65.99% (485/735) of adults and 83.41% (367/440) of infants had non-detectable pertussis-specific antibodies (<5 IU/mL). Our results showed that the majority of adults at a reproductive age and young infants are vulnerable to pertussis, suggesting that booster vaccinations in adults should be considered in this country.

Adverse events following immunization in pregnant women from Minas Gerais

OBJECTIVE:

To analyze the distribution of adverse events following immunization (AEFI) in pregnant women in the state of Minas Gerais, between 2015 and 2019.

METHODS:

This is an epidemiological, descriptive study conducted with AEFI data from 2015 to 2019, recorded in the Adverse Events Surveillance Information System, in the state of Minas Gerais (MG), Brazil. A total of 670 AEFI were analyzed in pregnant women. The estimates were presented in proportions, according to the year of occurrence, health macro-region of Minas Gerais and immunobiological administered.

RESULTS:

The year in which there were the most records was 2017 (36.8%). Among the 14 macro-regions, the ones with the lowest and highest number of records were the Vale do Jequitinhonha (0.5%) and Center (31.8%), respectively. The vaccines contraindicated during pregnancy represented 27.6% of the total notifications. The total of 69.5% of the cases were considered immunization errors. In 75.9% of the records, the variable of medical care was ignored, and in 73.7% of the cases no information on the evolution was presented.

CONCLUSION:

This study shows the need for continuing education for the multidisciplinary team, in order to reduce cases of AEFI and ensure the adequate completion of notifications by health professionals.

The Protective Role of Maternal Immunization in Early Life

With birth, the newborn is transferred from a quasi-sterile environment to the outside world. At this time, the neonatal immune system is inexperienced and continuously subject to a process of development as it encounters different antigenic stimuli after birth. It is initially characterized by a bias toward T helper 2 phenotype, reduced T helper 1, and cytotoxic responses to microbial stimuli, low levels of memory, and effector T and B cells and a high production of suppressive T regulatory cells. The aim of this setting, during fetal life, is to maintain an anti-inflammatory state and immune-tolerance. Maternal antibodies are transferred during pregnancy through the placenta and, in the first weeks of life of the newborn, they represent a powerful tool for protection. Thus, optimization of vaccination in pregnancy represents an important strategy to reduce the burden of neonatal infections and sepsis. Beneficial effects of maternal immunization are universally recognized, although the optimal timing of vaccination in pregnancy remains to be defined. Interestingly, the dynamic exchange that takes place at the fetal-maternal interface allows the transfer not only of antibodies, but also of maternal antigen presenting cells, probably in order to stimulate the developing fetal immune system in a harmless way. There are still controversial effects related to maternal immunization including the so called "immunology blunting," i.e., a dampened antibody production following infant's vaccination in those infants who received placentally transferred maternal immunity. However, clinical relevance of this phenomenon is still not clear. This review will provide an overview of the evolution of the immune system in early life and discuss the benefits of maternal vaccination. Current maternal vaccination policies and their rationale will be summarized on the road to promising approaches to enhance immunity in the neonate.

Social and obstetric inequalities and vaccination in pregnant women

OBJECTIVES

to analyze the association of socioeconomic level and obstetric characteristics with vaccine registration of pregnant women.

METHODS

cross-sectional study, performed with 480 women in puerperal. Vaccination of pregnant women was considered a dependent variable and as independent variables were age, skin color, education, steady union, paid work, and number of prenatal consultations. Association between variables was verified by the Poisson's regression model.

RESULTS

from 480 pregnant women's health cards, 10.63% had information on hepatitis B vaccination; 31.46% for tetanus; and 90% of the health cards had not register for influenza. There was an association of paid work and number of prenatal consultations with hepatitis B vaccination.

CONCLUSIONS

lower percentages in absence of vaccination occurred in women who were in the job market and had a higher number of prenatal consultations. This suggests that socioeconomic inequalities may interfere with the vaccination of pregnant women in health services.

Immunogenicity, transplacental transfer of pertussis antibodies and safety following pertussis immunization during pregnancy: Evidence from a randomized, placebo-controlled trial

BACKGROUND

Pertussis immunization during pregnancy is recommended in many countries. Data from large randomized controlled trials are needed to assess the immunogenicity, reactogenicity and safety of this approach.

METHODS

This phase IV, observer-blind, randomized, placebo-controlled, multicenter trial assessed immunogenicity, transplacental transfer of maternal pertussis antibodies, reactogenicity and safety of a reduced-antigen-content diphtheria-tetanus-three-component acellular pertussis vaccine (Tdap) during pregnancy. Women received Tdap or placebo at 27-36 weeks' gestation with crossover ≤ 72-hour-postpartum immunization. Immune responses were assessed before the pregnancy dose and 1 month after, and from the umbilical cord at delivery. Superiority (primary objective) was reached if the lower limits of the 95% confidence intervals (CIs) of the pertussis geometric mean concentration (GMC) ratios (Tdap/control) in cord blood were ≥ 1.5. Solicited and unsolicited adverse events (AEs) and pregnancy-/neonate-related AEs of interest were recorded.

RESULTS

687 pregnant women were vaccinated (Tdap: N = 341 control: N = 346). Superiority of the pertussis immune response (maternally transferred pertussis antibodies in cord blood) was demonstrated by the GMC ratios (Tdap/control): 16.1 (95% CI: 13.5-19.2) for anti-filamentous hemagglutinin, 20.7 (15.9-26.9) for anti-pertactin and 8.5 (7.0-10.2) for anti-pertussis toxoid. Rates of pregnancy-/neonate-related AEs of interest, solicited general and unsolicited AEs were similar between groups. None of the serious AEs reported throughout the study were considered related to maternal Tdap vaccination.

CONCLUSIONS

Tdap vaccination during pregnancy resulted in high levels of pertussis antibodies in cord blood, was well tolerated and had an acceptable safety profile. This supports the recommendation of Tdap vaccination during pregnancy to prevent early-infant pertussis disease.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: NCT02377349.

Interchangeability between pneumococcal conjugate vaccines for pediatric use: a systematic literature review

Introduction: Evidence on the interchangeability between the two pediatric pneumococcal conjugate vaccines (PCVs) - pneumococcal non-typeable Haemophilus influenzae protein D-conjugate vaccine (PHiD-CV) and 13-valent PCV (PCV13) - is limited but growing. We performed a systematic literature review to summarize evidence for PHiD-CV/PCV13 interchangeability regarding immunogenicity, safety, and effectiveness against pneumococcal disease. Areas covered: Seven records disclosing results from six studies on PHiD-CV/PCV13 interchangeability were identified. Four clinical trials showed that mixed schedules with a PHiD-CV-to-PCV13 switch at boosting or a PCV13-to-PHiD-CV switch during priming or at boosting were immunogenic with no apparent safety concerns. Two observational studies in the context of a programmatic PHiD-CV-to-PCV13 switch showed similarly high effectiveness against overall invasive pneumococcal disease with a mixed PHiD-CV/PCV13 schedule and a PCV13-only schedule. No effectiveness data for a PCV13-to-PHiD-CV switch and no immunogenicity/safety/effectiveness data for a PHiD-CV-to-PCV13 switch during priming were found. Expert opinion: For epidemiological or programmatic reasons, several local/national authorities have switched PCVs in their immunization programs. Consequently, children have received mixed schedules. Although herd immunity may obscure the individual effect, the limited data are reassuring. Additional evidence from these settings - especially effectiveness or impact data - may provide the necessary information for authorities to make informed decisions on interchanging PCVs.

Paediatric hospitalizations due to whooping cough in Spain (1997-2017)

This epidemiological survey estimates the burden of whooping cough in infants up to 12 months old in Spain during a twenty-one-year period (1997-2017). The survey was conducted by reviewing data from the Spanish Surveillance System for Hospital Data. All hospitalizations due to whooping cough for infants, reported during the 1997-2017 period, were analysed. Codes were selected from the International Classification of Diseases, 9th Revision, Clinical Modification diagnosis codes 033.0-033.9. To explore the latest national outbreak and the implementation of vaccination in pregnant women, analyses were stratified to compare the following periods: 1997-2010, 2011-2015 and 2016-2017. A total of 13,352 hospital discharges for whooping cough in infants up to 12 months old were reported. A total of 6850 discharges in the period 1997-2010, 5271 in the period 2011-2015 and 1231 in 2016-2017 were identified. The annual hospitalization rate prior to 2011 was 131.02 cases per 100,000 infants; in 2011-2015, the rate was significantly higher (250.13 cases per 100,000 infants) and in 2016-2017 it decreased (157.69 cases per 100,000 infants). Most of the cases (n = 11,446) occurred in infants under 4 months of age, with hospitalization rates of 328.80, 670.81 and 385.84 cases per 100,000 infants up to 4 months of age in the periods 1997-2010, 2011-2015 and 2016-17, respectively. Thirty-four deaths occurred in the period 1997-2010, 36 in the period 2011-2015 and 4 in 2016-2017. All of the deaths occurred in infants under 4 months old. The case fatality rate did not vary significantly across the study periods. Whooping cough infections concentrate in infants up to 4 months of age in Spain. Public health measures such as vaccination of pregnant women, caregivers, health care professionals and relatives, especially young parents, could reduce the hospitalization burden during the current outbreak.

Spatial analysis of vaccination against Hepatitis B in pregnant women in an urban Brazilian area

The objective of this article is to analyze the spatial distribution of Hepatitis B vaccine (HBVAC) of pregnant women. This is a cross-sectional study carried with 266 puerperae. The HBVAC record was obtained through the prenatal care booklet. The spatial scanning technique was used to detect a cluster of risk for the presence or absence of an HBVAC record. After this cluster identification, the individual and environmental variables were compared between the Coverage Areas of Basic Health Units (CAs-BHUs). The mean prevalence of non-HBVAC was 88.34%. Scan spatial scan analysis observed a cluster of a high prevalence of puerperae with a HBVAC record. Comparative analyses have shown that paid work and the number of prenatal visits are positively associated with an HBVAC record. Given the above, this work brings a reflection on possible disparities with other CAs-BHUs, besides the influence of the environmental perspective. It should be emphasized that the vaccination situation is influenced not only by factors intrinsic to the individuals. However, in this study, the results indicate that individual variables are predominantly mandatory in the decision of HBVAC uptake among pregnant women.

Maternal Vaccination as an Essential Component of Life-Course Immunization and Its Contribution to Preventive Neonatology

Maternal immunisation schedules are increasingly coming under the spotlight as part of the development of lifetime immunisation programmes for the role that they play in improving maternal, foetal, and neonatal health. Maternally-acquired antibodies are critical in protecting infants during the first months of their lives. Maternal immunisation was previously overlooked owing to concerns regarding vaccinations in this untested and high-risk population but is now acknowledged for its potential impact on the outcomes in many domains of foetal and neonatal health, aside from its maternal benefits. This article highlights the role that maternal immunisation may play in reducing infections in preterm and term infants. It explores the barriers to antenatal vaccinations and the optimisation of the immunisation uptake. This review also probes the part that maternal immunisation may hold in the reduction of perinatal antimicrobial resistance and the prevention of non-infectious diseases. Both healthcare providers and expectant mothers should continue to be educated on the importance and safety of the appropriate immunizations during pregnancy. Maternal vaccination merits its deserved priority in a life-course immunization approach and it is perhaps the only immunization whereby two generations benefit directly from a single input. We outline the current recommendations for antenatal vaccinations and highlight the potential advances in the field contributing to “preventive neonatology”.