Prospects for prevention of childhood infections by maternal immunization

Knowledge, Attitudes, and Practices Concerning Maternal Immunization Among Pregnant/Postpartum Women and Health Care Professionals in Peru

INTRODUCTION

For pregnant women, vaccination with inactivated influenza vaccine (IIV) and tetanus, diphtheria, acellular pertussis vaccine (Tdap) is recommended. In Peru, uptake is nonetheless low. A study was conducted to identify factors affecting maternal vaccination coverage. The study's primary objectives were to describe the knowledge, attitudes, and practices regarding maternal immunization among pregnant/postpartum women and health care professionals (HCPs). The secondary objective was to determine the vaccination coverage and the impact of Ministry of Health (MOH) recommendations.

METHODS

An observational multicenter, cross-sectional survey study was conducted from February 1, 2021 to June 30, 2021 in five cities in Peru. Two surveys were conducted to assess knowledge, attitudes, and practices concerning maternal immunization: one among pregnant/postpartum women and one among HCPs.

RESULTS

Participants were 668 pregnant/postpartum women with a mean age of 29.6 years and 219 HCPs-mostly midwives (46.6%) and obstetricians/gynecologists (44.7%). Of the pregnant/postpartum women, 66.9% knew that, in general, vaccinations are given for prevention, and 98.5% believed vaccines are important. Nonetheless, 69.6% of pregnant/postpartum women had poor or moderate knowledge of maternal vaccination. Disease knowledge of influenza (89.1%) and tetanus (87.0%) was high, while knowledge of pertussis (37.7%) was low. Women agreed/strongly agreed that they would get vaccinated with Tdap if a doctor (96.3%), midwife (88.9%), or nurse (72.0%) recommended it. Of the HCPs, 81.3% routinely recommended Tdap vaccination for pregnant women.

CONCLUSIONS

To enhance vaccine acceptance in pregnant women in Peru, we must improve knowledge of the diseases, MOH recommendations, and benefits of the offered vaccinations. HCPs could provide this vaccination knowledge and information along with their vaccination recommendation as the pregnant/postpartum women indicated they would take the vaccines if recommended by their HCPs. Our findings are important for the successful implementation of maternal immunization programs in Peru.

Effectiveness of BNT162b2 Vaccination During Pregnancy in Preventing Hospitalization for Severe Acute Respiratory Syndrome Coronavirus 2 in Infants

OBJECTIVE

To assess the clinical effectiveness of the BNT162b2 vaccine during pregnancy in preventing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) hospitalizations of infants.

STUDY DESIGN

A retrospective, multicenter, 1:3 case-control (test-negative) study. Symptomatic hospitalized infants less than 6 months of age, with a positive SARS-CoV-2 polymerase chain reaction test between January 3, 2021, and March 11, 2021, were matched by age and time to negative controls, hospitalized with symptoms compatible with SARS-CoV-2 infection. Mothers were defined as fully vaccinated who received 2 doses of BNT162b2 with the second given 2 weeks to 6 months before delivery; or partially vaccinated, if they received only 1 dose or 2 doses with the second given more than 6 months or less than 2 weeks before delivery. Severe SARS-CoV-2 was defined as a need for assisted ventilation.

RESULTS

We matched 116 SARS-CoV-2 positive infants with 348 negative controls with symptoms compatible with SARS-CoV-2 infection. The effectiveness of fully vaccinated mothers was 61.6% (95% CI, 31.9-78.4) and the effectiveness of partially vaccinated mothers was not significant. Effectiveness was higher in infants 0-2 vs 3-6 months of age. The effectiveness (57.1%; 95% CI, 22.8-76.4) was similar when excluding mothers who were infected with SARS-CoV-2 during pregnancy. The OR of severe infection in infants born to unvaccinated vs fully vaccinated mothers was 5.8.

CONCLUSIONS

At least 2 doses of BNT162b2 vaccine administered during the second or third trimester of pregnancy had an effectiveness of 61.6% in decreasing hospitalization for SARS-CoV-2 infection in infants less than 6 months of age.

Tetanus vaccine coverage in recommended and more than recommended doses among mothers in a West Cameroon health district: a cross sectional study

Background: Vaccination is the best way to protect newborns and mothers against tetanus. The number of doses of Td vaccine recommended by the Expanded Program of Immunization is based on documented protective immune response. During this decade, the Foumban Health District (FHD) was the seat of an epidemic despite the satisfactory administrative immunization coverage. This study was conducted in 2019 in the FHD to assess tetanus vaccine coverage among mothers for their last pregnancy and the cumulative number of vaccine doses administered to the mothers. Method: This was a descriptive cross-sectional study conducted in the FHD in 2019. Mothers living in the district with at least one child younger than five years were included and were selected by random stratified cluster sampling. Trained surveyors used a face-to-face questionnaire, data extraction grid and data-tracking grid to review and collect data from antenatal care booklets, vaccination cards and the women’s own reports of immunization. The immunization coverage per vaccine dose and vaccination completeness rate were estimated. Results: From 621 women visited, 602 (96.9%) responded. A total of 176/511 women (34.4%) had evidence of vaccination. For the last pregnancy, the two-dose immunization proportion was 21.7% (111/511) for documented coverage and 47.6% (243/511) for undocumented coverage. 306/570 women (53.7%) had received more than the recommended five doses necessary for lifetime protection. The recruitment, two and five doses completeness rates were 99.9% (569/570), 95.8% (546/570) and 65.3% (372/570), respectively. Conclusion: More than half of mothers received more doses of tetanus toxoid vaccine than necessary in FHD. This increased the resources needed and the cost of vaccination. Health personnel should be trained and supervised to assess pregnant women’s vaccination status before planning the number of vaccine doses to be administered during pregnancy.

Tetanus vaccine coverage in recommended and more than recommended doses among mothers in a West Cameroon health district: a cross sectional study

Background: Vaccination is the best way to protect newborns and mothers against tetanus. The number of doses recommended by the Expanded Program of Immunization is based on documented protective immune response. This study was conducted in 2019 in the Foumban Health District (FHD) to assess tetanus vaccine coverage among mothers for their last pregnancy and the cumulative number of vaccine doses administered to the mothers. Method: This was a descriptive cross-sectional study conducted in the FHD. Mothers living in the district with at least one child younger than five years were included and were selected by random stratified cluster sampling. Trained surveyors used a face-to-face questionnaire, data extraction grid and data-tracking grid to review and collect data from antenatal care booklets, vaccination cards and the women’s own reports of immunization. The immunization coverage per vaccine dose and vaccination completeness rate were estimated. Results: From 621 women visited, 602 (96.9%) responded. A total of 176/511 women (34.4%) had evidence of vaccination. For the last pregnancy, the two-dose immunization proportion was 21.7% (111/511) for documented coverage and 47.6% (243/511) for undocumented coverage. 306/570 women (53.7%) had received more than the recommended five doses necessary for lifetime protection. The recruitment, two and five doses completeness rates were 99.9% (569/570), 95.8% (546/570) and 65.3% (372/570), respectively. Conclusion: More than half of mothers received more doses of tetanus toxoid vaccine than necessary in FHD. This increased the resources needed and the cost of vaccination. Health personnel should be trained and supervised to assess pregnant women’s vaccination status before planning the number of vaccine doses to be administered during pregnancy.

Trends in Tdap vaccination among privately insured pregnant women in the United States, 2009-2016

BACKGROUND

Infants younger than 6 months are at increased risk of complications and mortality from pertussis infection. In October 2012, the Advisory Committee on Immunization Practices revised its recommendation to include a Tdap dose during each pregnancy, ideally between 27 and 36 weeks gestation.

OBJECTIVE

Assess trends in Tdap vaccination coverage among privately insured pregnant women from 2009 to 2016 including timing of Tdap vaccination (before, during, or after pregnancy), trimester of vaccination for women vaccinated during pregnancy, and missed vaccination opportunities for unvaccinated women. Identify factors associated with vaccination during the optimal period of 27-36 weeks gestation.

STUDY DESIGN

Retrospective analysis of privately insured women 15-49 years who delivered live births during 2009-2016 conducted using 2009-2016 MarketScan data. Tdap vaccination coverage and the timing of Tdap vaccine administration were assessed for women continuously enrolled from 6 months before pregnancy to 1 month after delivery. Multivariable logistic regression was performed to identify factors independently associated with receipt of Tdap vaccine at 27-36 weeks gestation.

RESULTS

Tdap vaccination coverage during pregnancy increased from 0.4% in 2009 to 6.2% in 2012 and to 53.2% in 2016. The proportion of vaccinated women receiving Tdap at 27-36 weeks gestation increased from <10% in 2009 to nearly 90% in 2016, with most vaccination occurring at 27-32 weeks gestation. Women of older age, residing in a metropolitan statistical area, residing outside the South, and having a capitated health insurance plan were more likely to receive Tdap at 27-36 weeks gestation than their counterparts. Among women not vaccinated during pregnancy, 77.7% had a pregnancy-related medical claim between 27 and 36 weeks gestation.

CONCLUSION

Tdap vaccination coverage during pregnancy increased significantly from 2009 to 2016, with the greatest increase occurring after the revised Advisory Committee on Immunization Practices recommendation. Most women who did not receive Tdap vaccine had a missed vaccination opportunity during pregnancy, indicating potential for much higher vaccination coverage and consequent infant protection against pertussis.

Review of vaccination in pregnancy to prevent pertussis in early infancy

Maternal pertussis vaccination has been introduced in several countries to protect infants from birth until routine infant vaccination takes place. This review assesses existing evidence on the effectiveness and safety of immunization in pregnancy. The search was finalized in April 2017 and was based on searches using several databases. The selection criteria included any experimental or observational study reporting on the immunogenicity, effectiveness or safety of vaccination with a pertussis-containing vaccine in pregnant women and their infants. Following de-duplication and exclusions, we identified 8395 studies, which were reduced to 46 for inclusion. The overall risk of bias was low, with the exception of some early studies and pharmacovigilance safety data. The evidence demonstrates efficient transplacental transfer of maternal antibodies in infants whose mothers were vaccinated with Tdap or Tdap/IPV in pregnancy, with good evidence that this protects against disease in young infants. Safety studies covering more than 150 000 women vaccinated mostly in the late second or third trimesters are generally consistent and provide reassurance of no significant increased risk of recognized maternal conditions or of adverse events (including congenital anomalies) in infants born to vaccinated women. The clinical significance of reduced seroconversion to pertussis following routine immunization is not yet clear, but no increased risk of pertussis in infants whose mothers were vaccinated in pregnancy was found following primary immunizations in North American and English studies. Most post-booster studies suggest that any blunting effect is short-lived and that longer-term protection in infants from active immunization is not compromised.

Recent developments in the understanding and use of anthrax vaccine adsorbed: achieving more with less

Anthrax Vaccine Adsorbed (AVA, BioThrax™) is the only Food and Drug Administration (FDA) approved vaccine for the prevention of anthrax in humans. Recent improvements in pre-exposure prophylaxis (PrEP) use of AVA include intramuscular (IM) administration and simplification of the priming series to three doses over 6 months. Administration IM markedly reduced the frequency, severity and duration of injection site reactions. Refinement of animal models for inhalation anthrax, identification of immune correlates of protection and cross-species modeling have created opportunities for reductions in the PrEP booster schedule and were pivotal in FDA approval of a post-exposure prophylaxis (PEP) indication. Clinical and nonclinical studies of accelerated PEP schedules and divided doses may provide prospects for shortening the PEP antimicrobial treatment period. These data may assist in determining feasibility of expanded coverage in a large-scale emergency when vaccine demand may exceed availability. Enhancements to the AVA formulation may broaden the vaccine's PEP application.

Immunization against pertussis in adolescents and adults

Pertussis is a highly contagious infectious disease caused by Bordetella pertussis that can be extremely serious, particularly in young infants. For many years the efforts of health authorities throughout the world to prevent pertussis had the main goals of reducing the morbidity of infants and children under 5 years of age, maintaining protection for several years during the school-age period and developing a significant herd immunity to directly and indirectly reduce the risk of the spread of the disease among young infants and the risk of transmission of the infection from preschool children to infants. However, the increased risk of B. pertussis infection among adolescents and adults due to the waning immunity to this bacterium induced by vaccines and natural infection seems to be the main reason for the resurgence of pertussis. We discuss the reasons for the administration of pertussis vaccines to individuals for whom they were previously not recommended, the expected results of the administration of additional pertussis vaccine doses and the differences in the administration of pertussis vaccines in different countries. An analysis of the literature revealed several reports indicating the need for the modification of immunization schedules against pertussis, with booster doses among adolescents and the need for the vaccination of pregnant women. However, to monitor the true epidemiology of pertussis, effective programmes to collect pertussis cases, adequate reporting systems and vaccination coverage monitoring should be urgently implemented.

Strategies to decrease pertussis transmission to infants

The Global Pertussis Initiative (GPI) is an expert scientific forum addressing the worldwide burden of pertussis, which remains a serious health issue, especially in infants. This age cohort is at risk for developing pertussis by transmission from those in close proximity. Risk is increased in infants aged 0 to 6 weeks, as they are too young to be vaccinated. Older infants are at risk when their vaccination schedules are incomplete. Infants also bear the greatest disease burden owing to their high risk for pertussis-related complications and death; therefore, protecting them is a high priority. Two vaccine strategies have been proposed to protect infants. The first involves vaccinating pregnant women, which directly protects through the passive transfer of pertussis antibodies. The second strategy, cocooning, involves vaccinating parents, caregivers, and other close contacts, which indirectly protects infants from transmission by preventing disease in those in close proximity. The goal of this review was to present and discuss evidence on these 2 strategies. Based on available data, the GPI recommends vaccination during pregnancy as the primary strategy, given its efficacy, safety, and logistic advantages over a cocoon approach. If vaccination during pregnancy is not feasible, then all individuals having close contact with infants <6 months old should be immunized consistent with local health authority guidelines. These efforts are anticipated to minimize pertussis transmission to vulnerable infants, although real-world effectiveness data are limited. Countries should educate lay and medical communities on pertussis and introduce robust surveillance practices while implementing these protective strategies.

Pertussis vaccines: position paper of Indian Academy of Pediatrics (IAP)

Pertussis continues to be a major public health problem in both developing and developed countries. Data on exact burden and incidence of pertussis in the developing countries including India is sparse. However, the disease is widespread, even if not adequately measurable. Pertussis incidence has been increasing steadily in the last decade especially in industrialized countries. Outbreaks are reported from many developed countries in recent years despite widespread use of acellular pertussis vaccines with high coverage. The current status of coverage with pertussis vaccines is still sub-optimal in many states of the country. There is scarcity of data on vaccine efficacies of both whole-cell and acellular pertussis vaccines from India and other developing countries. Most of the recommendations on pertussis vaccination are based on the experience gained from the use of them in industrialized countries. Taking in to the consideration the recent evidence of faster waning of acellular pertussis vaccines in comparison to whole-cell vaccines and superior priming with whole-cell than acellular pertussis vaccines, Indian Academy of Pediatrics has now revised its recommendations pertaining to pertussis immunization in office practice. The Academy has now proposed whole-cell pertussis vaccines for the primary series of infant vaccination. Guidelines are also now issued on the preference of a particular acellular product. The Academy has also recommended use of Tdap during each pregnancy to provide protection to the very young infants. It urges the Government of India to initiate studies on the quality of available pertussis vaccines in India and to set indigenous national guidelines for the manufacturers to produce and market different pertussis vaccines in the country.

Decline of IgG pertussis toxin measured in umbilical cord blood, and neonatal and early infant serum

Maternal pertussis-specific antibodies are passively acquired by infants during pregnancy. An IgG pertussis toxin (IgG-PT) concentration of >20 U/ml is considered to protect neonates against pertussis. To evaluate the IgG concentration at birth and during the first two months of life, we examined the IgG-PT concentration in the umbilical cord blood and three times during the neonatal and early infant period. IgG-PT was measured by validated IgG-specific enzyme-linked immunosorbent assays (ELISA) in umbilical cord blood and in Guthrie card blood samples of umbilical cord blood in 2,790 children, born between 1 August 2006 and 1 December 2008. These measurements were comparable. All children with concentrations of IgG-PT >30 U/ml were included. IgG-PT was also measured in Guthrie card blood samples, when the neonates or early infants were 5 days, 1 month and 2 months old. The mean concentrations of IgG-PT were calculated. The mean concentration of IgG-PT in umbilical cord blood was 60.1 U/ml (LN 4.1; 0.6 SD; n = 103). At the age of 5 days, 1 month and 2 months, the mean concentration of IgG-PT was 40.6 U/ml (LN 3.7; 0.5 SD; n = 103), 20.7 U/ml (LN 3.0; 0.7 SD; n = 62) and 16.7 U/ml (LN 2.8; 0.9 SD; n = 61), respectively. Four percent of the neonates had a concentration of IgG-PT >30 U/ml in umbilical cord blood, which declined to levels around the concentration needed for protection against pertussis (>20 U/ml) in the first two months of life. Hence, it is of great importance to further investigate the safety of maternal immunisation during pregnancy to prevent life-threatening pertussis in newborns.

Pediatric sepsis: important considerations for diagnosing and managing severe infections in infants, children, and adolescents

Sepsis is the leading cause of death in children worldwide. Although the diagnosis and management of sepsis in infants and children is largely influenced by studies done in adults, there are important considerations relevant for pediatrics. This article highlights pediatric-specific issues related to the definition of sepsis and its epidemiology and management. We review how the capacity of the immune system to respond to infection develops over early life. We also bring attention to primary immune deficiencies that should be considered in children recurrently infected with specific types of organisms. The management of pediatric sepsis must be tailored to the child’s age and immune capacity, and to the site, severity, and source of the infection. It is important for clinicians to be aware of infection-related syndromes that primarily affect children. Although children in developed countries are more likely to survive severe infections than adults, many survivors have chronic health impairments.

Immune responses in infants whose mothers received Tdap vaccine during pregnancy

BACKGROUND

The effect of maternal Tdap vaccination on infant immunologic responses to routine pediatric vaccines is unknown.

METHODS

This was a cohort study of infants whose mothers received or did not receive Tdap vaccine during pregnancy. Maternal and cord blood samples were collected at delivery; infant blood samples were collected before and after primary series and booster dose of diphtheria, tetanus, and acellular pertussis (DTaP) and other vaccines. Geometric mean antibody concentrations or titers to pertussis, hepatitis B, tetanus, diphtheria, Haemophilus influenzae type b and polio antigens were measured. Mean maternal-to-cord blood antibody ratios were calculated.

RESULTS

At delivery, maternal and cord antibody concentrations to pertussis antigens were higher in the Tdap group (n=16) than control group (n=54; maternal: 1.9- to 20.4-fold greater; cord: 2.7- to 35.5-fold greater). Increased antibody concentrations persisted for infants at first DTaP (3.2- to 22.8-fold greater). After primary series, antibody concentrations to pertussis antigens were lower in Tdap group (0.7- to 0.8-fold lower), except for fimbriae types 2 and 3 (FIM) (1.5-fold greater). Antibody concentrations to pertussis antigens before and after booster dose were comparable (prebooster: Tdap group 1.0- to 1.2-fold higher than controls; postbooster: 0.9- to 1.0-fold lower). Differences in FIM values at these time points are difficult to interpret, due to varying FIM content among DTaP vaccines administered to infants in both groups.

CONCLUSIONS

Maternal Tdap immunization resulted in higher pertussis antibody concentrations during the period between birth and the first vaccine dose. Although slightly decreased immune responses following the primary series were seen compared with controls, differences did not persist following the booster.

Neonatal infections in Saudi Arabia: association with C-reactive protein, CRP -286 (C>T>A) gene polymorphism and IgG antibodies

Background

C-reactive protein (CRP) is a nonspecific, acute-phase protein that rises in response to infectious and non-infectious inflammatory processes. Infections are the single largest cause of neonatal deaths globally.

The primary aim of this study is to examine the association between CRP gene polymorphism and serum levels of CRP in correlation with early onset sepsis (EOS) infection in newborns living in Taif city, Saudi Arabia. The second aim is to examine the relationship between specific IgG/IgG subclasses and early onset sepsis (EOS) infection among these newborns.

Methods

Staphylococcus aureus (S. aureus) is one of the most common organisms related to sepsis infection in the newborn at King Abdel Aziz Specialist Hospital (KAASH). This study was conducted in Taif city, at KAASH’s neonatal intensive care unit between March and August 2012. Neonates were consecutively enrolled onto the study having met our inclusion criteria (as per our research protocol).

The CRP concentration level was analysed using NycoCard® CRP Single Test. CRP -286 (C>T>A) A polymorphisms were analyzed using Pyrosequencing technology for CRP genotyping. IgG subclasses were analysed in the study population using ELISA.

Result

Logistic regression analyses showed that the AA and AC genotypes were negatively associated amongst EOS neonates compared to suspected neonates. The frequency of CC and CT were significantly associated with the EOS neonates compared to the suspected group. The levels of specific IgG1, IgG2 and IgG3 antibodies were significantly lower amongst EOS compared to the suspected group.

Conclusions

Taken together, the CRP-286 (C>T>A) A genotype polymorphism and specific IgG antibodies isotype levels can contribute to a reduced risk of EOS. Furthermore, CRP has a potential use in detecting EOS in neonates, which may mean earlier detection and management of EOS and subsequently better clinical outcome.

Prevention of cholestasis in the murine rotavirus-induced biliary atresia model using passive immunization and nonreplicating virus-like particles

Biliary atresia (BA) is a neonatal cholangiopathy of unknown etiology that results in obliteration of bile ducts and is the primary indication for liver transplant in children. A murine model of BA, which involves infecting newborn mice with rhesus rotavirus (RRV) and leads to development of an obstructive cholangiopathy, has provided a model to assess measures to prevent and treat BA. We used this mouse model of RRV-induced BA to determine if passive immunization of pups using maternal immunization [injection of dams with non-replicating rotavirus (RV) virus-like particles (VLPs) or live RRV] or injection of pups with RV immune serum would protect these RRV-infected neonates from developing BA (measured using cholestasis). Parenteral immunization of mouse dams with two formulations of VLPs (containing viral proteins 2/6 or 2/6/7) resulted in a significant increase in serum RV antibody, and pups born to these immunized dams were protected from developing cholestasis following neonatal infection with RRV. Serum RV-specific antibody with titers of ≥400-800 in dams significantly protected pups from developing cholestasis, and a significant trend of increasing protection with high titers was observed (p<0.0001). Cholestatic pups had lower levels of RV serum antibody and higher serum (p<0.01) and liver (p<0.05) RV antigen compared to healthy pups. Passive transfer of low-titer (1600; p<0.05) or high-titer (25,600; p<0.01) RV immune serum to neonatal pups prior to RRV infection also protected them from developing cholestasis. Together, these findings indicate that passively acquired, neutralizing or non-neutralizing RV serum antibody attenuates viral replication and protects pups against disease in the RRV BA model. Early reduction of viral load by clearance with RV-specific antibody is likely a critical determinant of disease in this model.

Determination of vaccination status of pregnant women during pregnancy and the affecting factors

AIMS AND OBJECTIVES

To determine the vaccination status of pregnant women during pregnancy and factors affecting their vaccination.

BACKGROUND

Immunisation provided through vaccination is one of the most effective ways to reduce or prevent the risks of disease, disability and death. Maternal and newborn health may be protected and morbidity may be decreased through vaccinating pregnant women when necessary.

DESIGN

This was a descriptive and cross-sectional survey.

METHODS

This study was conducted in a university hospital in Ankara, Turkey, between 01 March and 31 May 2010. The study was carried out with 198 healthy pregnant women who had completed the 26th week of gestation. Data were collected using the data collection form composed of questions enquiring about the demographic and obstetric features of pregnant women and whether or not they knew that vaccinations could be given during pregnancy, and which vaccines could be used during pregnancy, which vaccine/vaccines they had previously received and the reasons for having been vaccinated or not.

RESULTS

Approximately half of the participants had received at least one of the vaccines that may be used in pregnancy (52·0%). The pregnant women received vaccinations for tetanus (47·0%), H1N1 (9·1%), seasonal influenza (3·0%) and hepatitis B (0·5%), respectively. The pregnant women who had been educated about vaccinations had been vaccinated at a statistically significantly higher rate compared with those who had not.

CONCLUSION

This study revealed that pregnant women's knowledge about the required vaccines during pregnancy affected their behaviour towards vaccination. Acquiring knowledge about vaccines that may be used during pregnancy from health personnel is effective to increase vaccination. This result may be interpreted as 'acquired information affects behaviour towards vaccination'.

RELEVANCE TO CLINICAL PRACTICE

Providing information about immunisation to pregnant women at the antenatal clinic is important in terms of maternal and newborn health. Nurses and midwives working in the antenatal field should be sufficiently educated about immunisation.

Knowledge and attitudes of postpartum women toward immunization during pregnancy and the peripartum period

Influenza and pertussis prevention in young infants requires immunizing pregnant women and all caregivers (cocooning). We evaluated the knowledge and attitude of postpartum women about these two recommendations. A survey of predominantly Hispanic, underinsured, medically underserved postpartum women in Houston, Texas was performed during June 2010 through July 2012. Five hundred eleven postpartum women [mean age 28.8 y (18-45); 94% Hispanic] with a mean of 3 children (1-12) participated. Ninety-one (17.8%) were first-time mothers. Four hundred ninety-six (97.1%) received prenatal care; care was delayed in 24.3%. Only 313 (61.3%) received vaccine education while pregnant, and 291 (57%) were immunized. Four hundred seventy-four women (93%) were willing to be immunized during pregnancy if recommended by their healthcare provider, (the most trusted information source for 62%). Immunization of infants or infant caregivers had been discussed with 41% and 10% of mothers, respectively. Two hundred thirty women (45%) had received influenza vaccine; most intended to (79%) or had already received (15%) tetanus, diphtheria, and acellular pertussis (Tdap) vaccine. Preferred locations for cocooning were hospital or community clinics (97%). Insufficient knowledge (46.6%), cost (31.4%), lack of transportation (26%), work commitments (13.3%), and fear of needles (13.3%) were perceived barriers to cocooning. Level of formal education received by mothers had no effect on the quantity or quality of immunization education received during PNC or their attitude toward immunization. Immunization during pregnancy and cocooning, if recommended by providers, are acceptable in this high-risk population. Healthcare providers, as reported in infant studies, have the greatest influence on vaccine acceptance by pregnant and postpartum women.

Re-emergence of pertussis: what are the solutions?

Whooping cough, due to Bordetella pertussis and Bordetella parapertussis, is an important cause of childhood morbidity and mortality. Despite widespread pertussis immunization in childhood, there are an estimated 50 million cases and 300,000 deaths due to pertussis globally each year. Infants who are too young to be vaccinated, children who are partially vaccinated and fully-vaccinated persons with waning immunity are especially vulnerable to disease. Since pertussis is one of the vaccine-preventable diseases on the rise, additional vaccine approaches are needed. These approaches include vaccination of newborns, additional booster doses for older adolescents and adults, and immunization of pregnant women with existing vaccines. Innovative new vaccines are also being studied. Each of these options will be discussed and their potential impact on pertussis control assessed.

Distinguishing true coagulase-negative Staphylococcus infections from contaminants in the neonatal intensive care unit

OBJECTIVE

To characterize true coagulase-negative Staphylococcus (CoNS) infections in infants receiving neonatal intensive care.

STUDY DESIGN

Retrospective cohort study of neonatal intensive care unit (NICU) infants with clinical sepsis and CoNS isolated from ≥ 2 blood cultures (BCs) or one BC and a sterile site (proved infection) or CoNS isolated from one BC and deemed significant after blinded data review (probable infection).

RESULT

In all, 98% of 40 proved and 96% of 55 probable infections occurred in infants with birth weight (BW) <2000 g and gestation <34 weeks. Total central lines (CLs) placed, but not CL duration or presence in situ, predicted proved (odds ratio (OR) 3.5, 95% confidence interval (CI) 1.4 to 8.3; P=0.005) and probable infection (OR 2.7, 95% CI 1.3 to 5.6; P=0.007) by multivariate analysis as did lethargy and gastric residuals.

CONCLUSION

True CoNS infection is unlikely in infants with BW >2000 g and gestation >34 weeks. Total CL required for care, lethargy and gastric residuals predicted true CoNS infection.

Overcoming liability concerns in vaccine trials involving pregnant women

Without the protection of vaccines, the health of pregnant women may be compromised. But assessing the safety and efficacy of vaccines in pregnancy requires research in pregnancy. Furthermore, vaccinating women while they are pregnant may convey immunity to the fetus in utero, but assessing this possible benefit of maternal immunization also requires research. This article argues that one factor inhibiting vaccine research involving pregnant women is that vaccine manufacturers fear incurring liability if they fund such research. We argue that vaccine research in pregnancy can be ethical, and we explore some methods for overcoming vaccine manufacturers' fear of liability.

Background rates of adverse pregnancy outcomes for assessing the safety of maternal vaccine trials in sub-Saharan Africa

Background

Maternal immunization has gained traction as a strategy to diminish maternal and young infant mortality attributable to infectious diseases. Background rates of adverse pregnancy outcomes are crucial to interpret results of clinical trials in Sub-Saharan Africa.

Methods

We developed a mathematical model that calculates a clinical trial's expected number of neonatal and maternal deaths at an interim safety assessment based on the person-time observed during different risk windows. This model was compared to crude multiplication of the maternal mortality ratio and neonatal mortality rate by the number of live births. Systematic reviews of severe acute maternal morbidity (SAMM), low birth weight (LBW), prematurity, and major congenital malformations (MCM) in Sub-Saharan African countries were also performed.

Findings

Accounting for the person-time observed during different risk periods yields lower, more conservative estimates of expected maternal and neonatal deaths, particularly at an interim safety evaluation soon after a large number of deliveries. Median incidence of SAMM in 16 reports was 40.7 (IQR: 10.6–73.3) per 1,000 total births, and the most common causes were hemorrhage (34%), dystocia (22%), and severe hypertensive disorders of pregnancy (22%). Proportions of liveborn infants who were LBW (median 13.3%, IQR: 9.9–16.4) or premature (median 15.4%, IQR: 10.6–19.1) were similar across geographic region, study design, and institutional setting. The median incidence of MCM per 1,000 live births was 14.4 (IQR: 5.5–17.6), with the musculoskeletal system comprising 30%.

Interpretation

Some clinical trials assessing whether maternal immunization can improve pregnancy and young infant outcomes in the developing world have made ethics-based decisions not to use a pure placebo control. Consequently, reliable background rates of adverse pregnancy outcomes are necessary to distinguish between vaccine benefits and safety concerns. Local studies that quantify population-based background rates of adverse pregnancy outcomes will improve safety assessment of interventions during pregnancy.

Benefits to mother and child of influenza vaccination during pregnancy

Influenza virus infection contributes to substantial morbidity and mortality globally. Included in the list of groups at higher risk of either influenza infection or severe complications following influenza infection are pregnant women and their newborns. Influenza vaccination offers a safe and effective means to prevent or lessen the severity of influenza infections. Recent research has helped elucidate the impact of influenza infection and vaccination on pregnant women and their newborn children and young infants. This review summarizes recent findings in this area and identifies additional gaps in the evidence base that need to be addressed to appropriately inform vaccination policies worldwide, to protect pregnant women and their children from influenza and related complications.

Maternal immunization with pneumococcal surface protein A protects against pneumococcal infections among derived offspring

Pathogen-specific antibody plays an important role in protection against pneumococcal carriage and infections. However, neonates and infants exhibit impaired innate and adaptive immune responses, which result in their high susceptibility to pneumococci. To protect neonates and infants against pneumococcal infection it is important to elicit specific protective immune responses at very young ages. In this study, we investigated the protective immunity against pneumococcal carriage, pneumonia, and sepsis induced by maternal immunization with pneumococcal surface protein A (PspA). Mother mice were intranasally immunized with recombinant PspA (rPspA) and cholera toxin B subunit (CTB) prior to being mated. Anti-PspA specific IgG, predominantly IgG1, was present at a high level in the serum and milk of immunized mothers and in the sera of their pups. The pneumococcal densities in washed nasal tissues and in lung homogenate were significantly reduced in pups delivered from and/or breast-fed by PspA-immunized mothers. Survival after fatal systemic infections with various types of pneumococci was significantly extended in the pups, which had received anti-PspA antibody via the placenta or through their milk. The current findings strongly suggest that maternal immunization with PspA is an attractive strategy against pneumococcal infections during early childhood. (191 words)

Impact of maternal immunization on influenza hospitalizations in infants

We sought to determine whether maternal vaccination during pregnancy was associated with a reduced risk of laboratory-confirmed influenza hospitalizations in infants <6 months old. Active population-based, laboratory-confirmed influenza surveillance was conducted in children hospitalized with fever and/or respiratory symptoms in 3 US counties from November through April during the 2002 through 2009 influenza seasons. The exposure, influenza vaccination during pregnancy, and the outcome, positive/negative influenza testing among their hospitalized infants, were compared using logistic regression analyses. Among 1510 hospitalized infants <6 months old, 151 (10%) had laboratory-confirmed influenza and 294 (19%) mothers reported receiving influenza vaccine during pregnancy. Eighteen (12%) mothers of influenza-positive infants and 276 (20%) mothers of influenza-negative infants were vaccinated (unadjusted odds ratio, 0.53; 95% confidence interval, 0.32-0.88 and adjusted odds ratio, 0.52; 95% confidence interval, 0.30-0.91). Infants of vaccinated mothers were 45-48% less likely to have influenza hospitalizations than infants of unvaccinated mothers. Our results support the current influenza vaccination recommendation for pregnant women.

An evaluation of the emerging interventions against Respiratory Syncytial Virus (RSV)-associated acute lower respiratory infections in children

Background

Respiratory Syncytial Virus (RSV) is the leading cause of acute lower respiratory infections (ALRI) in children. It is estimated to cause approximately 33.8 million new episodes of ALRI in children annually, 96% of these occurring in developing countries. It is also estimated to result in about 53,000 to 199,000 deaths annually in young children. Currently there are several vaccine and immunoprophylaxis candidates against RSV in the developmental phase targeting active and passive immunization.

Methods

We used a modified CHNRI methodology for setting priorities in health research investments. This was done in two stages. In Stage I, we systematically reviewed the literature related to emerging vaccines against RSV relevant to 12 criteria of interest. In Stage II, we conducted an expert opinion exercise by inviting 20 experts (leading basic scientists, international public health researchers, international policy makers and representatives of pharmaceutical companies). The policy makers and industry representatives accepted our invitation on the condition of anonymity, due to the sensitive nature of their involvement in such exercises. They answered questions from the CHNRI framework and their “collective optimism” towards each criterion was documented on a scale from 0 to 100%.

Results

In the case of candidate vaccines for active immunization of infants against RSV, the experts expressed very low levels of optimism for low product cost, affordability and low cost of development; moderate levels of optimism regarding the criteria of answerability, likelihood of efficacy, deliverability, sustainability and acceptance to end users for the interventions; and high levels of optimism regarding impact on equity and acceptance to health workers. While considering the candidate vaccines targeting pregnant women, the panel expressed low levels of optimism for low product cost, affordability, answerability and low development cost; moderate levels of optimism for likelihood of efficacy, deliverability, sustainability and impact on equity; high levels of optimism regarding acceptance to end users and health workers. The group also evaluated immunoprophylaxis against RSV using monoclonal antibodies and expressed no optimism towards low product cost; very low levels of optimism regarding deliverability, affordability, sustainability, low implementation cost and impact on equity; moderate levels of optimism against the criteria of answerability, likelihood of efficacy, acceptance to end-users and health workers; and high levels of optimism regarding low development cost. They felt that either of these vaccines would have a high impact on reducing burden of childhood ALRI due to RSV and reduce the overall childhood ALRI burden by a maximum of about 10%.

Conclusion

Although monoclonal antibodies have proven to be effective in providing protection to high-risk infants, their introduction in resource poor settings might be limited by high cost associated with them. Candidate vaccines for active immunization of infants against RSV hold greatest promise. Introduction of a low cost vaccine against RSV would reduce the inequitable distribution of burden due to childhood ALRI and will most likely have a high impact on morbidity and mortality due to severe ALRI.

Maternal immunization to modulate the development of allergic response and pathogen infections

This article reviews recent experimental approaches of preventive strategies regarding allergy and infections by pathogens, particularly in early childhood, by targeting maternal immunomodulation. Basic research is essential to understand maternal vaccination as a strategy to control allergic disease and bacterial and viral infections; thus, providing support for future translational research. The environmental stimuli and host genetic factors, along with maternal influences in early life when immune systems are developing and during postnatal life, are essential for the decision between tolerance induction or allergen sensitization. Maternal immunomodulation strategies should serve as a challenge when attempting to halt the spread of allergy responses and viral infections, until the innate and adaptive arms of the immune system of the neonates are competent.

Neonatal sepsis and neutrophil insufficiencies

Sepsis has continuously been a leading cause of neonatal morbidity and mortality despite current advances in chemotherapy and patient intensive care facilities. Neonates are at high risk for developing bacterial infections due to quantitative and qualitative insufficiencies of innate immunity, particularly granulocyte lineage development and response to infection. Although antibiotics remain the mainstay of treatment, adjuvant therapies enhancing immune function have shown promise in treating sepsis in neonates. This article reviews current strategies for the clinical management of neonatal sepsis and analyzes mechanisms underlying insufficiencies of neutrophil defense in neonates with emphasis on new directions for adjuvant therapy development.

Pertussis antibodies in postpartum women and their newborns

OBJECTIVE

To (1) determine the proportion of mothers and infants who had levels of IgG antibody to pertussis antigens predicted to be potentially protective at delivery; (2) evaluate the efficiency of maternal-infant antibody transport; (3) extrapolate infant antibody titers at 6 weeks; and (4) identify maternal factors associated with potentially protective infant antibodies.

STUDY DESIGN

Sera from mother-infant pairs from February 2006 through to April 2007 were tested for antibody to pertussis antigens by standardized ELISA (enzyme-linked immunosorbent assay). Potentially protective antibody levels were defined as >5 ELISA units (EU) for pertussis toxin (PT), and >10 EU for fimbriae (FIM) and pertactin (PRN). Serological evidence of previous maternal infection was defined from antibody to four antigens by k-means cluster analysis.

RESULT

In total, 21% (17/81) of mothers and 26% (21/81) of infants had potentially protective antibody levels at delivery. Mean infant-maternal antibody ratios for PT, FIM and PRN were 1.26, 1.36 and 1.31, respectively. At 6 weeks, 11% (9/81) of infants were predicted to have potentially protective antibody levels. Using cluster analysis, 9% (7/81) of mothers had evidence of previous pertussis infection. Infants born to these mothers were predicted to be more likely to have potentially protective antibodies at 6 weeks (43%) than those born to mothers without previous infection (8%) (P=0.03).

CONCLUSION

Approximately 75% of infants were born with pertussis antibody levels lower than the modest levels associated with potential protection. Despite effective antibody transfer, nearly 90% of infants were predicted to have little antibody by 6 weeks. Maternal immunization before or during pregnancy might simulate previous pertussis infection and help protect infants through the first months of life.

Pregnancy and infant outcomes in the clinical trials of a human papillomavirus type 6/11/16/18 vaccine: a combined analysis of five randomized controlled trials

OBJECTIVE

To present a combined analysis of the pregnancy outcomes for women aged up to 45 years enrolled in five phase III clinical studies of the prophylactic quadrivalent human papillomavirus 6/11/16/18 vaccine.

METHODS

Twenty thousand five hundred fifty-one women aged 15-45 years received quadrivalent HPV vaccine or placebo at day 1 and months 2 and 6. Urine pregnancy tests were performed immediately before each injection; participants testing positive were not vaccinated. Women who became pregnant after enrollment were discontinued from further vaccination until resolution of pregnancy. All pregnancies were followed for outcomes.

RESULTS

During the studies, 1,796 vaccine and 1,824 placebo recipients became pregnant, resulting in 2,008 and 2,029 pregnancies with known outcomes. No significant differences were noted overall for the proportions of pregnancies resulting in live birth, fetal loss, or spontaneous abortion. A total of 40 neonates born to vaccinated women and 30 neonates born to women given placebo had one or more congenital anomalies (P=.20). The anomalies were diverse and consistent with those most commonly observed in the general population. The vaccine was well tolerated among women who became pregnant.

CONCLUSION

Administration of quadrivalent human papillomavirus vaccine to women who became pregnant during the phase III clinical trials did not appear to negatively affect pregnancy outcomes. The vaccine is a U.S. Food and Drug Administration pregnancy category B medication (animal studies revealed no evidence of fetal harm, but there are no adequate and well-controlled studies in pregnant women); however, vaccination is not recommended during pregnancy. Postlicensure surveillance is ongoing.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, www.clinicaltrials.gov, NCT00092521, NCT00092534, NCT00092495, NCT00092547 and NCT00090220.

LEVEL OF EVIDENCE

II.

The human neonatal B cell response to respiratory syncytial virus uses a biased antibody variable gene repertoire that lacks somatic mutations

The human Ab repertoire exhibits restrictions during fetal life characterized by biases of variable gene segment usage and lack of junctional diversity. We tested the hypotheses that Ab repertoire restriction persists in the early postnatal period and contributes to the observed poor quality of specific Ab responses made by neonates to viruses and vaccines. We analyzed the molecular determinants of B cell responses in humans to respiratory syncytial virus (RSV). Analysis of the variable gene segment usage of adult RSV-specific B cells revealed a repertoire profile in these cells similar to that seen in randomly selected B cells, which was V(H)3-dominant. Four gene segments (V(H)3-23, V(H)3-30, V(H)3-33 and V(H)4-04) accounted for almost half of the V(H) genes used. In contrast, very young infant RSV-specific antibodies exhibited a biased repertoire characterized by comparable use of the V(H)1, V(H)3, and V(H)4 families, and less common use of the four immunodominant gene segments. Infants and children older than three months used an antibody repertoire similar to that of adults. Mutational analysis revealed that the antibody variable genes of infants under three months of age also possessed significantly fewer somatic mutations in both framework and complementarity-determining region (CDR) regions than those of adults, even in a child with recurrent RSV infection. These data suggest that neonates use a biased antibody gene repertoire that is less V(H)3-focused and that possesses a dramatically lower frequency of somatic mutations. These biased features of the RSV-specific repertoire likely contribute to the poor functional Ab response in very young infants.

Group B streptococcus and early-onset sepsis in the era of maternal prophylaxis

Despite an era of marked success with universal screening, Group B Streptococcus (GBS) continues to be an important cause of early-onset sepsis, and thus remains a significant public health issue. Improved eradication of GBS colonization and disease may involve universal screening in conjunction with rapid diagnostic technologies or other novel approaches. Given the complications and potential limitations associated with maternal intrapartum prophylaxis, however, vaccines may be the most effective means of preventing neonatal GBS disease. The global utility of conjugated GBS vaccines may be hampered by the variability of serotypes in diverse populations and geographic locations. Modern technologies, such as those involving proteomics and genomic sequencing, are likely to hasten the development of a universal vaccine against GBS.

Sepsis in the neonate

In the neonatal intensive care unit, critical care nurses who are not advanced practice nurses cannot make the medical diagnosis of infection/sepsis in the neonate. Even so, the critical care nurse has a critical role in dealing with sepsis infection. The nurse must (1) have a high index of suspicion about the risk of infection, (2) be able to recognize septic/infected newborns, (3) report related concerns to the physician or advanced practice nurse, and (4) advocate on behalf of the infant to ensure a timely diagnostic workup and empiric antibiotics. This article is a guide for understanding issues related to sepsis in the neonatal intensive care unit.

Effectiveness of maternal influenza immunization in mothers and infants

BACKGROUND

Young infants and pregnant women are at increased risk for serious consequences of influenza infection. Inactivated influenza vaccine is recommended for pregnant women but is not licensed for infants younger than 6 months of age. We assessed the clinical effectiveness of inactivated influenza vaccine administered during pregnancy in Bangladesh.

METHODS

In this randomized study, we assigned 340 mothers to receive either inactivated influenza vaccine (influenza-vaccine group) or the 23-valent pneumococcal polysaccharide vaccine (control group). Mothers were interviewed weekly to assess illnesses until 24 weeks after birth. Subjects with febrile respiratory illness were assessed clinically, and ill infants were tested for influenza antigens. We estimated the incidence of illness, incidence rate ratios, and vaccine effectiveness.

RESULTS

Mothers and infants were observed from August 2004 through December 2005. Among infants of mothers who received influenza vaccine, there were fewer cases of laboratory-confirmed influenza than among infants in the control group (6 cases and 16 cases, respectively), with a vaccine effectiveness of 63% (95% confidence interval [CI], 5 to 85). Respiratory illness with fever occurred in 110 infants in the influenza-vaccine group and 153 infants in the control group, with a vaccine effectiveness of 29% (95% CI, 7 to 46). Among the mothers, there was a reduction in the rate of respiratory illness with fever of 36% (95% CI, 4 to 57).

CONCLUSIONS

Inactivated influenza vaccine reduced proven influenza illness by 63% in infants up to 6 months of age and averted approximately a third of all febrile respiratory illnesses in mothers and young infants. Maternal influenza immunization is a strategy with substantial benefits for both mothers and infants. (ClinicalTrials.gov number, NCT00142389.)

Fatal influenza B virus pneumonia in a preterm neonate: case report and review of the literature

Although less common than influenza A, influenza B infections can cause significant mortality and morbidity in children who are immunocomprised and have underlying medical conditions. We report a preterm neonate with fatal influenza B virus pneumonia. This infant presented with signs and symptoms indistinguishable from any other cause of sepsis.