Vaccination during pregnancy: current and possible future recommendations

Research Priorities for Maternal Immunization

BACKGROUND

The maternal immunization platform has multiple vaccines already being utilized with more vaccines being considered.

METHODS

We describe areas with knowledge gaps regarding maternal immunization including (1) pathogen, (2) vaccine product, (3) vaccine strategy, (4) implementation research and (5) Regulatory and Public Health Policy.

RESULTS

Despite advances in clinical research during pregnancy, many questions remain regarding vaccine administration, products, coadministration of vaccines and vaccine acceptance. Issues regarding maternal antibody transfer in high-risk pregnancies need further study.

CONCLUSIONS

Moving new maternal vaccines forward will take support from a broad array of experts.

Attitudes towards Maternal Immunisation of Polish Mothers: A Cross-Sectional, Non-Representative Study

INTRODUCTION

Vaccination protects pregnant women against dangerous infectious diseases and contributes to disease prevention for the child until their vaccination schedule begins. Vaccination behaviour is related to attitudes concerning vaccine prevention.

MATERIALS AND METHODS

This cross-sectional, non-representative study was conducted among Polish mothers using a diagnostic survey. We used the Vaccination Attitudes Examination (VAX) Scale. The author's questionnaire included questions concerning experiences with adult and maternal vaccinations, as well as sociodemographic data.

RESULTS

Among the 375 respondents, more than half (n = 208, 55.47%) received at least one vaccine during pregnancy. The majority of respondents had a university education (n = 356, 94.93%). There was no statistically significant difference in terms of receiving vaccines during pregnancy between respondents with and without a healthcare education (p = 0.230). A logistic regression model indicated that women who were vaccinated outside pregnancy for COVID-19 (OR 4.61, 2.60-8.22) and influenza (OR 7.14, 3.58-14.25) were statistically significantly more likely to be vaccinated during pregnancy. There were statistically significant differences between women who were vaccinated during pregnancy and those who did not receive maternal immunisation in three subscales of the VAX Scale: Mistrust of Vaccine Benefit, Concerns about Commercial Profiteering, and Preference for Natural Immunity (p < 0.001). The most frequently indicated reason for a woman's decision to be vaccinated was concern for the health and safety of the unborn child (n = 196, 94.23%). In contrast, women who were not vaccinated reported fear for the health and safety of the unborn child (n = 88, 52.69%).

CONCLUSIONS

A key point may be to contribute to the vaccinology education of healthcare professionals, who play an important role in pregnant women's decision to be vaccinated. However, our results may be disrupted because the majority of the women in our study had a university education.

Acceptance and uptake of vaccines against tetanus, influenza, pertussis, and COVID-19 among pregnant and postpartum women in low- and middle-income countries: a systematic review and meta-analysis protocol

BACKGROUND

Pregnant women, fetuses, and neonates are particularly vulnerable to vaccine-preventable diseases (VPDs). These VPDs are associated with high morbidity and mortality among expectant mothers and their fetuses and neonates. Vaccination during pregnancy can protect the expectant mother from VPDs to which she may be especially vulnerable while pregnant. In addition, the passive transfer of maternal neutralizing immunoglobulin G (IgG) and secretory immunoglobulin A (IgA) also protects the fetus against congenital infections and may further protect the neonate from infection during the first few months of life. Despite this, coverage of recommended maternal vaccines remains suboptimal globally, especially in resource-constrained settings. Determinants of vaccine acceptance and uptake are frequently understudied in low- and middle-income countries (LMICs) and among specific groups such as pregnant and postpartum women. This proposed systematic review will assess the acceptance and uptake of vaccines against tetanus, influenza, pertussis, and COVID-19 among pregnant and postpartum women in LMICs.

METHODS

A Boolean search strategy employing common and medical subject heading (MeSH) terms for tetanus, influenza, pertussis, and COVID-19 vaccines, as well as vaccine acceptance, hesitancy, together with uptake, pregnancy, and postpartum, will be used to search electronic databases for relevant literature published between 2009 and 2024. Only studies conducted in LMICs that investigated determinants of acceptance, hesitancy, and uptake of tetanus, influenza, pertussis, and COVID-19 vaccines among pregnant and postpartum women will be eligible for inclusion in the review. The quality and the risk of bias of all eligible full-text articles will be assessed using the Joanna Briggs Institute's (JBI) critical appraisal tools.

DISCUSSION

This protocol proposes a systematic review and meta-analysis that aims to assess the uptake of maternal vaccines and to systematically appraise and quantify determinants of the acceptance and uptake of recommended vaccines during pregnancy and postpartum in LMICs. A better understanding of these factors and how they influence maternal vaccine decision-making will enable public health practitioners as well as global and national policymakers to design more effective interventions as we look towards expanding the scope and reach of maternal immunization programs.

Pregnant individuals perspectives towards receiving COVID-19 vaccination during their pregnancy: an in-depth qualitative study

Introduction

Pregnant individuals have an increased risk of severe illness from coronavirus disease 2019 (COVID-19) infection. Vaccination is an effective strategy to prevent severe illness and complications for pregnant individuals. Pregnant individuals are often excluded from research and remain hesitant to receive vaccination against COVID-19. It is pivotal to study factors related to vaccine uptake and hesitancy among pregnant individuals. We studied barriers and facilitators for pregnant individuals choice and motivation regarding vaccination against COVID-19 during pregnancy to aid future pregnant individuals in their decision to vaccinate against various infectious agents.

Methods

In this qualitative study, pregnant individuals were interviewed between October 2021 and January 2022 using a semi-structured approach. A topic list was used to explore their feelings, perceptions and ideas regarding vaccination against COVID-19 during pregnancy. Interviews were transcribed verbatim and thematic analyses was performed using MAX QDA.

Results

After nine interviews, saturation was reached. Three main themes were identified that influenced pregnant individuals choice and motivation regarding vaccination: health consequences, ambiguity of information and societal motivation. Health consequences mainly concerned the effect for their offspring, and the unknown long-term effects of COVID-19 vaccination. The advice from the Dutch institute for Public Health and Environment changed from not vaccinating pregnant individuals after release of the developed vaccine, to routinely vaccinating all pregnant individuals after research data were available from the United States of America (USA). This change of policy fuelled doubt and confusion for vaccination. Arguments in favor of vaccination from the social perspective were specific behaviour rules and restrictions due to the pandemic. E.g. without vaccination people were unable to travel abroad and having to take a COVID-19 test every time entering a public place.

Conclusion

Pregnant individuals need clear, unambiguous information concerning health consequences, short- and long-term, particularly for their offspring, in the decision-making process regarding COVID-19 vaccination. Additionally, the societal perspective needs to be addressed. Besides the aforementioned themes, general counselling should focus on misperceptions of vaccine safety and the role of misinformation which are also important in the non-pregnant population. This study underlines the importance of including pregnant individuals in research programs to obtain specific information targeted to their needs.

Passive Immunization Strategies to Prevent Severe Respiratory Syncytial Virus Infection Among Newborns and Young Infants

Newborns and young infants are at risk for severe respiratory syncytial virus (RSV) lower respiratory tract infection. Passive immunity is the mainstay of infection prevention in this cohort. Transplacental transfer of maternal antibodies provides the newborn with immediate protection from life-threatening infections, however, is dependent upon gestational age, birth weight, mother's age, recent maternal vaccination, maternal nutritional status, maternal immunocompetence and medical conditions, and placental integrity. Efficient transplacental transfer of RSV-neutralizing antibodies have led to the development and approval of maternal RSV immunization for the protection of the newborn. Additionally, administration of RSV-specific antibodies to infants leads to high serum titers of RSV-neutralizing antibodies and further protection from severe disease.

Does the SARS-CoV-2 mRNA vaccine and its serum IgG levels affect fertility treatments and obstetric outcomes? An observational cohort study

BACKGROUND

Although there are some data regarding the COVID-19 vaccine and in in vitro fertilization (IVF) treatments, its potential impact in terms of serum immunoglobulin G (IgG) levels has not been evaluated prospectively. This study aimed to assess the effect of COVID-19 vaccine and IgG levels on IVF outcomes.

METHODS

This observational, cohort study was conducted at a referral IVF unit. Couples undergoing IVF treatment during the COVID-19 vaccination period were recruited from March-April 2021. The study compared 38 women who had received the Pfizer mRNA COVID-19 vaccination to 10 women who had not and were not infected by the virus. We also compared pre- and post-vaccination IVF treatments for 24 women. The relation between serologic titers and IVF treatment outcomes was also assessed.

RESULTS

No significant difference was found between the vaccinated and unvaccinated/uninfected groups regarding the main outcome measures. However, there was a trend toward a higher pregnancy rate for the unvaccinated group (57% vs. 23%, p = 0.078) but no difference in delivery rate (p = 0.236), gestational week (p = 0.537) or birth rate (p = 0.671).

CONCLUSION

We cautiously state that the COVID-19 mRNA vaccine does not affect fertility outcomes, including fertilization, pregnancy and delivery rates, obstetric outcomes, and semen parameters, regardless of measured IgG levels.

The Multi-faceted Effects of COVID-19 on Female Reproductive Health: An Updated Narrative Review

Concerns about the SARS-CoV-2 pandemic's possible impact on sexual and reproductive health have grown significantly. In this narrative review, the latest research on the effects of SARS-CoV-2 infection on several facets of sexual and reproductive health is reviewed. The review starts initially by going through the possible consequences of SARS-CoV-2 on female menstrual cycles. The virus may interfere with the menstrual cycle, which could affect hormone synthesis and endometrial reactions, according to newly available evidence. Menstrual blood loss may be impacted by COVID-19's potential to influence endothelial cell function and systemic hemostasis. Hypothalamic amenorrhea may be brought on by severe COVID-19 disease. There is little research on this subject, although most women resume their regular menstrual cycles after 1-2 months of recuperation. The review also examines how SARS-CoV-2 infection may affect assisted reproductive technology (ART) treatments. There are few clinical data, although some research points to potential effects on embryo quality. Overall, ART results, however, did not materially change from the time before the epidemic. Obstetric problems are more likely when SARS-CoV-2 infection occurs during pregnancy, especially in the third trimester. Even though the maternal death rate is still low, pregnant women, especially those with comorbidities, are more likely to experience serious sickness. The review emphasizes how the COVID-19 vaccine affects menstrual cycles, showing brief, modest modifications without serious health hazards. Also included are the psychological effects of family planning choices during the pandemic. In conclusion, this narrative review offers a thorough assessment of the complicated and changing effects of SARS-CoV-2 on sexual and reproductive health. The different requirements of people and couples during and after the pandemic are highlighted, underscoring the necessity for ongoing study and specialized healthcare practices.

RSV Prefusion F Protein-Based Maternal Vaccine - Preterm Birth and Other Outcomes

BACKGROUND

Vaccination against respiratory syncytial virus (RSV) during pregnancy may protect infants from RSV disease. Efficacy and safety data on a candidate RSV prefusion F protein-based maternal vaccine (RSVPreF3-Mat) are needed.

METHODS

We conducted a phase 3 trial involving pregnant women 18 to 49 years of age to assess the efficacy and safety of RSVPreF3-Mat. The women were randomly assigned in a 2:1 ratio to receive RSVPreF3-Mat or placebo between 24 weeks 0 days and 34 weeks 0 days of gestation. The primary outcomes were any or severe medically assessed RSV-associated lower respiratory tract disease in infants from birth to 6 months of age and safety in infants from birth to 12 months of age. After the observation of a higher risk of preterm birth in the vaccine group than in the placebo group, enrollment and vaccination were stopped early, and exploratory analyses of the safety signal of preterm birth were performed.

RESULTS

The analyses included 5328 pregnant women and 5233 infants; the target enrollment of approximately 10,000 pregnant women and their infants was not reached because enrollment was stopped early. A total of 3426 infants in the vaccine group and 1711 infants in the placebo group were followed from birth to 6 months of age; 16 and 24 infants, respectively, had any medically assessed RSV-associated lower respiratory tract disease (vaccine efficacy, 65.5%; 95% credible interval, 37.5 to 82.0), and 8 and 14, respectively, had severe medically assessed RSV-associated lower respiratory tract disease (vaccine efficacy, 69.0%; 95% credible interval, 33.0 to 87.6). Preterm birth occurred in 6.8% of the infants (237 of 3494) in the vaccine group and in 4.9% of those (86 of 1739) in the placebo group (relative risk, 1.37; 95% confidence interval [CI], 1.08 to 1.74; P = 0.01); neonatal death occurred in 0.4% (13 of 3494) and 0.2% (3 of 1739), respectively (relative risk, 2.16; 95% CI, 0.62 to 7.56; P = 0.23), an imbalance probably attributable to the greater percentage of preterm births in the vaccine group. No other safety signal was observed.

CONCLUSIONS

The results of this trial, in which enrollment was stopped early because of safety concerns, suggest that the risks of any and severe medically assessed RSV-associated lower respiratory tract disease among infants were lower with the candidate maternal RSV vaccine than with placebo but that the risk of preterm birth was higher with the candidate vaccine. (Funded by GlaxoSmithKline Biologicals; ClinicalTrials.gov number, NCT04605159.).

The safety and immunogenicity of vaccines administered to pregnant women living with HIV: a systematic review and meta-analysis

Background

Human Immunodeficiency Virus (HIV)-exposed uninfected (HEU) infants have a higher burden of infectious diseases related morbidity and mortality compared with HIV-unexposed uninfected (HUU). Immunization of pregnant women living with HIV (PWLWH) could reduce the severity and burden of infectious diseases for HEU in early infancy.

Methods

We conducted a systematic review of safety and immunogenicity of vaccines administered to PWLWH and meta-analyses to test the overall effect of immunogenicity comparing pregnant women without HIV (PWWH) to PWLWH. We searched MEDLINE, Embase, Web of Science, Virtual Health Library and Cochrane databases in accordance with PRISMA guidelines for randomized controlled trials and observational studies. Review articles, case series, conference abstracts, and animal studies were excluded. Studies were included from inception to 6th September 2023, with no language restrictions. Random effects meta-analyses were performed for immunogenicity using Review manager (RevMan) analysis software version 5.4.1, Geometric Mean Titer (GMT) values were transformed to obtain the mean and standard deviation within RevMan, the effect size was computed and reported as mean difference with respective 95% confidence intervals. The review was registered with PROSPERO CRD42021289081.

Findings

We included 12 articles, comprising 3744 pregnant women, 1714 were PWLWH given either influenza, pneumococcal or an investigational Group B streptococcal (GBS) vaccine. Five studies described safety outcomes, and no increase in adverse events was reported in PWLWH compared to PWWH. The GMT increase from baseline to 28-35 weeks post vaccination in HA units ranged from 12.4 (95% CI: 9.84-14.9) to 238.8 (95% CI: 0.35-477.9). Meta-analyses of influenza vaccines showed the pooled geometric mean difference in Hemagglutination Inhibition (HAI) titers post vaccination was 56.01 (95% CI: 45.01-67.01), p < 0.001. The increase was less in PWLWH when compared with PWWH: -141.76 (95% CI: -194.96, -88.55), p < 0.001.

Interpretation

There are limited data on the safety and immunogenicity of vaccines given to PWLWH making policy consideration in this group difficult when new vaccines are introduced. With new vaccines on the horizon, PWLWH need to be included in studies to promote vaccine confidence for this special population.

Funding

This work was funded by Medical Research Council Joint Clinical Trials Round 9 [MR/T004983/1].

Interventions to Improve Knowledge, Attitudes, and Uptake of Recommended Vaccines during Pregnancy and Postpartum: A Scoping Review

Tetanus, pertussis, influenza, and COVID-19 vaccines are recommended for the prevention of related morbidity and mortality during pregnancy and postpartum. Despite the established benefits of vaccination for prenatal and postnatal women, maternal vaccination is not universally included in routine antenatal programs, especially in low- and middle-income countries. Furthermore, the uptake of recommended vaccines among pregnant and postpartum women remains below optimum globally. This review aimed to map the evidence on interventions to improve knowledge, attitudes, and uptake of recommended vaccines among pregnant and postpartum women. We conducted a comprehensive and systematic search for relevant literature in PubMed, Scopus, Web of Science, EBSCOhost, and Google Scholar. Overall, 29 studies published between 2010 and 2023 were included in this review. The majority (n = 27) of these studies were from high-income countries. A total of 14 studies focused on the influenza vaccine, 6 on the Tdap vaccine, 8 on both influenza and Tdap vaccines, and only one study on the COVID-19 vaccine. Patient-centered interventions predominated the evidence base (66%), followed by provider-focused (7%), health system-focused (10%), and multilevel interventions (17%). Overall, the effect of these interventions on knowledge, attitudes, and uptake of maternal vaccines was variable.

Vaccination during pregnancy: A golden opportunity to embrace

Immunization strategies are part of routine pregnancy care to prevent infectious diseases in the mother, the fetus, and the newborn. Maternal immunization recommendations followed the recognition of the consequences of infectious diseases in pregnancy, including vertical transmission and perinatal consequences. The recent COVID-19 pandemic highlighted the issue of vaccination among pregnant individuals. Recommendations vary globally; however, Tdap, influenza, and, recently, COVID-19 vaccines are routinely recommended during pregnancy. There are several new maternal immunization products in the pipeline, including those directed against malaria, cytomegalovirus, Group B Streptococcus, herpes simplex virus, and respiratory syncytial virus. Important challenges must be addressed in all countries to guarantee that pregnant individuals and their babies receive the best care possible, including uptake of recommended immunizations by their entire target population groups. These challenges include disseminating appropriate data for vaccine recommendations and many others, such as ensuring stakeholder endorsement, achieving in-country distribution and administration, adequate vaccine supply, and a well-organized healthcare system, ideally offering the immunization free of charge. More recently, the hesitancy of pregnant women to receive immunizations highlights the relevance of cultural aspects and other contextual factors affecting vaccine uptake among pregnant individuals.

Covid-19 vaccination during pregnancy: A mixed-methods study of attitudes in a sample of Italian women and the role of health professionals' communication

OBJECTIVES

We examined Italian pregnant women's attitudes about the diphtheria, tetanus, and pertussis (DTP) vaccine, seasonal influenza, and Covid-19 vaccines, healthcare professionals' (HP) communication, reasons and potential predictors for non-adherence.

METHODS

From August 2021 to January 2022, we carried out a cross-sectional study in Italy using an online self-administered questionnaire addressed to women of age and pregnant, designed using LimeSurvey and disseminated through social media. Questions explored vaccination attitude/perceptions, satisfaction, and trust in HPs' information. Thematic analysis of free-text responses was performed using MaxQDA 2022. Statistical analyses were performed using STATA.

RESULTS

1594 responses were obtained. 52% of women hesitated to be vaccinated against Covid-19 while pregnant. Information received by HPs was deemed incomplete by 56% of participants, unclear by 52%, and untrustworthy by 46%; 49% felt unsupported in their decision-making process. This variable was one predictor of vaccine hesitancy together with concern about vaccine safety in the multivariate model. The analysis of open-ended questions revealed a pervasive feeling of dissatisfaction.

CONCLUSION

The perceived lack of adequate communication and support by HPs affected pregnant women's decision-making process on Covid-19 vaccination.

PRACTICE IMPLICATIONS

HPs need to understand and communicate the importance of vaccination during pregnancy, learning to better tailor their messages.

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.

Immunisation against COVID-19 in Pregnancy and of Women Planning Pregnancy

Following reports of the first human SARS-CoV2 infection in December 2019 from Wuhan Province, China, there was such rapid spread that by March 2021, the World Health Organization (WHO) had declared a pandemic. Over 6.5 million people have died from this infection worldwide, although this is most likely an underestimate. Until vaccines became available, mortality and severe morbidity were costly in terms of life lost as well as the cost of supporting the severely and acutely ill. Vaccination changed the landscape, and following worldwide adoption, life has gradually been returning to normal. The speed of production of the vaccines was unprecedented and undoubtedly ushered in a new era in the science of fighting infections. The developed vaccines were on the already known platforms for vaccine delivery: inactivated virus, virus vector, virus-like particles (VLP) subunit, DNA and mRNA. The mRNA platform was used for the first time to deliver vaccines to humans. An understanding of these platforms and the pros and cons of each are important for clinicians who are often challenged by the recipients on the advantages and risks of these vaccines. These vaccines have so far and reassuringly been shown to be safe in reproduction (with no effect on gametes) and pregnancy (not associated with congenital malformations). However, safety remains paramount and continuing vigilance is critical, especially against rare fatal complications such as vaccine-induced thrombocytopenia and myocarditis. Finally, the waning immunity months after vaccination means repeated immunisation is likely to be ongoing, but just how often and how many such revaccinations should be recommended remains uncertain. Research into other vaccines and alternate delivery methods should continue as this infection is likely to be around for a long time.

Strategies to Prevent Early and Late-Onset Group B Streptococcal Infection via Interventions in Pregnancy

Group B Streptococcus is a Gram-positive bacterium that typically colonizes 10-30% of pregnant women, causing chorioamnionitis, preterm birth, and stillbirth, as well as neonatal sepsis and meningitis with early-onset disease (EOD) or late-onset disease (LOD) due to ascending infection or transmission during delivery. While there are some differences between EOD and LOD in terms of route of transmission, risk factors, and serotypes, the only preventive approach currently is maternal intrapartum antibiotic prophylaxis (IAP) which will not be able to fully address the burden of the disease since this has no impact on LOD. Probiotics and immunization in pregnancy may be more effective than IAP for both EOD and LOD. There is mixed evidence of probiotic effects on the prevention of GBS colonization, and the data from completed and ongoing clinical trials investigating different GBS vaccines are promising. Current vaccine candidates target bacterial proteins or the polysaccharide capsule and include trivalent, tetravalent, and hexavalent protein-polysaccharide conjugate vaccines. Some challenges in developing novel GBS vaccines include the lack of a correlate of protection, the potential for serotype switching, a need to understand interactions with other vaccines, and optimal timing of administration in pregnancy to maximize protection for both term and preterm infants.

Covid-19 vaccination in pregnancy

Pregnancy is an independent risk factor for severe covid-19. Vaccination is the best way to reduce the risk for SARS-CoV-2 infection and limit its morbidity and mortality. The current recommendations from the World Health Organization, Centers for Disease Control and Prevention, and professional organizations are for pregnant, postpartum, and lactating women to receive covid-19 vaccination. Pregnancy specific considerations involve potential effects of vaccination on fetal development, placental transfer of antibodies, and safety of maternal vaccination. Although pregnancy was an exclusion criterion in initial clinical trials of covid-19 vaccines, observational data have been rapidly accumulating and thus far confirm that the benefits of vaccination outweigh the potential risks. This review examines the evidence supporting the effectiveness, immunogenicity, placental transfer, side effects, and perinatal outcomes of maternal covid-19 vaccination. Additionally, it describes factors associated with vaccine hesitancy in pregnancy. Overall, studies monitoring people who have received covid-19 vaccines during pregnancy have not identified any pregnancy specific safety concerns. Additional information on non-mRNA vaccines, vaccination early in pregnancy, and longer term outcomes in infants are needed. To collect this information, vaccination during pregnancy must be prioritized in vaccine research.

Tetanus in Uganda: clinical outcomes of adult patients hospitalized at a tertiary health facility between 2011 and 2020

Background

Tetanus is a vaccine-preventable infectious disease associated with high mortality rates. Increased vaccination coverage globally and locally has resulted in substantial declines in the number of individuals diagnosed with tetanus. We report annual trends in tetanus admissions and deaths over a decade at a national referral hospital in Uganda.

Methods

This was a retrospective cohort study, using data from an electronic database of patients admitted to medical wards at a national referral hospital between 2011 and 2020. Data were abstracted on demographic characteristics, that is, length of hospital stay and mortality outcome. Admission and mortality rate trends were analyzed using the Mann-Kendall’s trend test, whereas Kaplan-Meier survival curves were used to compare gender survival rates.

Results

During the study period, 459 individuals were admitted with tetanus. Of these, 85.8% (394 of 459) were males, and 26.1% (120 of 459) were aged 20 years or less. Overall, 48.8% (224 of 459) participants died, 85.3% (191 of 224) of whom were males (85.3%, n = 191), although females had a higher mortality rate (50.8%, 33 of 65 vs 48.5%, 191 of 394). Those aged 31–40 years accounted for 23.7% (53 of 224) of the deaths; and 88.7% (197 of 224) of the deaths occurred within the first 7 days of admission. The total number of tetanus admissions declined (Tau_A = −.6444, P = .0116). However, mortality rates remained stable (Tau_A = .0222, P > .999). The average length of hospital stay was 8.1 days (standard deviation, 7.5; range, 1–46).

Conclusions

Although tetanus admissions declined, mortality rate remained high. Males were disproportionately affected. We recommend quality-of-care audits for inpatient care improvement and more research on the determinants of infection and mortality to inform vaccination for at-risk men.

Assessment of Anti m-RNA SARS-CoV-2 (BNT162b2) Antibody Titres in Mother and Child Pairs of Breastfeeding Women Vaccinated Post-Delivery

The global response to the COVID-19 pandemic has been successfully driven by efforts to ramp up access to vaccines. Pregnant or breastfeeding women and their children have not benefited from the vaccines despite their susceptibility to the virus. We investigated whether women who were offered vaccination after delivery passively transferred protective antibodies to their infants via breast milk. Serum was collected from breast feeding mother–infant pairs and analysed for levels of antibodies to the SARS-CoV-2 spike protein using the CLIA chemiluminescence technique. Data were analysed for the significance of the differences using the Mann–Whitney U test and the Spearman’s rank correlation coefficient to determine the strength of the correlation. A total of 13 mothers, mean age 34.86 (95%CI = 33.21–36.48) years and their infants, mean age 15.77 (95%CI = 11.24–20.29) months were enrolled. The mothers had completed their courses of the mRNA BNT162b2 SARS-CoV-2 vaccine during breastfeeding, 8.3 (95%CI = 7.24–9.36) months before the study. All 13 mothers had detectable antibodies to the SARS-CoV-2 spike protein, mean 1252, (95%CI = 736–1769) BAU/mL. Antibodies were detected in 3/13 (23%) breast-fed infants mean 322, (95%CI = 252–897) BAU/mL. There was no correlation between the maternal and infant IgG antibody titres. The time-lag since full vaccination did not correlate to the presence of antibodies in infant sera. Maternal or infant ages did not correlate to the presence of antibodies. Although some children (23%) had anti-SARS-CoV-2 antibodies, there was no association between vaccine-induced COVID-19 spike protein specific maternal IgG antibody titres and the presence of antibodies in the breastfed infants. The data show that the transfer of passive immunity to infants following post-partum vaccination with the mRNA BNT162b2 SARS-CoV-2 vaccine may be infrequent in this population.

Kinetics of Maternally Derived Anti-Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Antibodies in Infants in Relation to the Timing of Antenatal Vaccination

BACKGROUND

SARS-CoV-2 infection during early infancy can result in severe disease. We evaluated the durability of maternally-derived anti-SARS-CoV-2 antibodies in infants and its relation to antenatal vaccination timing.

METHODS

Sera were prospectively collected at birth and 3 months after delivery from mother-infant pairs following antenatal BNT162b2 vaccination. SARS-CoV-2 receptor binding domain (RBD)-specific IgG levels and neutralizing activity were evaluated.

RESULTS

56 mother-infant pairs were included: 15 (26.8%) were vaccinated in the first trimester, 16 (28.6%) in the second trimester, and 25 (44.6%) in the third trimester.At the time of delivery, all neonates were positive for anti-RBD-specific IgG with a median concentration of 4046 [IQR 2446-7896] AU/mL, with the highest concentration found after third trimester vaccination (median 6763 [IQR 3857-12561] AU/mL). At 3 months after delivery, anti RBD-specific IgG levels in infants significantly waned with a median concentration of 545 [IQR 344-810] AU/mL (P < .001). The half-life of anti-RBD-specific IgG was 66 days among mothers and 30 days among infants. While at the time of delivery, all neonates had detectable neutralizing activity regardless of gestational age at vaccination, at 3-months of age, a higher proportion of infants born to mothers vaccinated in third trimester had persistent neutralizing activity as compared to those born to mothers vaccinated in second trimester.

CONCLUSIONS

Maternal vaccination leads to efficient transplacental antibody transfer, with persistent anti-SARS-CoV-2 antibodies detected at 3 months of age in all infants. The observed effect of antenatal immunization timing on the kinetics of maternally-derived antibodies may have implications for SARS-CoV-2 vaccination strategies.

Determinants of neonatal sepsis among neonates admitted to the neonatal intensive care unit of public hospitals in Hawassa City Administration, Sidama Region, Ethiopia, 2020: an unmatched, case-control study

OBJECTIVE

This study was conducted to assess the determinants of neonatal sepsis in the neonatal intensive care units of public hospitals in Hawassa City Administration, Sidama Region, Ethiopia, in 2020.

DESIGN

Institutional-based, unmatched, case-control study.

SETTING

The study was conducted in three public hospitals (Hawassa University Teaching Hospital, Adare General Hospital and Hawela Tula Primary Hospital) of Hawassa City, Ethiopia.

PARTICIPANTS

A total of 331 (110 cases and 221 controls) neonates with their index mothers were included in the study from 1 August to 30 September 2020.

OUTCOME MEASURES

A pretested, interviewer-administered questionnaire and data extraction checklist were used to collect data. Data were coded and entered into EpiData V.3.1 before being exported to SPSS V.20 for analysis. The factors associated with neonatal sepsis were assessed using bivariable and multivariable logistic regression analyses. P value of less than 0.05 was used to establish statistically significant association of variables.

RESULTS

Caesarean section delivery (adjusted OR (AOR)=2.56, 95 % CI 1.3 to 5.00), maternal anaemia (AOR=2.58, 95 % CI 1.45 to 4.6) and lack of vaccination with tetanus toxoid (AOR=3.5, 95% CI 2.07 to 6.19) were all identified as factors significantly associated with neonatal sepsis.

CONCLUSIONS

Caesarean section delivery, maternal history of anaemia and lack of vaccination with tetanus toxoid were found to be risk factors for neonatal sepsis. Establishing preconception care practice, strengthening the quality of antenatal care and standardising infection prevention practice are needed to improve neonatal health.

Assessing Community Acceptance of Maternal Immunisation in Rural KwaZulu-Natal, South Africa: A Qualitative Investigation

Despite the significant benefits of maternal immunisation, uptake remains low in many parts of the world. In this qualitative study, we aimed to assess the factors that influence pregnant women’s decision to engage with maternal immunisation in rural KwaZulu-Natal, South Africa. We conducted in-depth interviews with a total of 28 purposively sampled pregnant women and key informants using semi-structured topic guides. Data analysis was conducted using a modified Health Belief Model framework that included constructs of barriers to action, modifying factors of cue to action and perceived social norms. The findings show that traditional customs and institutional barriers such as low-quality health service delivery, long queues, and distance to the health facilities, immunisation vaccine stockouts and low levels of maternal knowledge influence the choice and decision to engage with maternal immunisation. Understanding health-related behaviours and addressing barriers to care is important in facilitating vaccination uptake. This study contributes to the understanding of maternal immunisation uptake in low-resource settings.

Novel Strategies to Inhibit Pertussis Toxin

Pertussis, also known as whooping cough, is a respiratory disease caused by infection with Bordetella pertussis, which releases several virulence factors, including the AB-type pertussis toxin (PT). The characteristic symptom is severe, long-lasting paroxysmal coughing. Especially in newborns and infants, pertussis symptoms, such as leukocytosis, can become life-threatening. Despite an available vaccination, increasing case numbers have been reported worldwide, including Western countries such as Germany and the USA. Antibiotic treatment is available and important to prevent further transmission. However, antibiotics only reduce symptoms if administered in early stages, which rarely occurs due to a late diagnosis. Thus, no causative treatments against symptoms of whooping cough are currently available. The AB-type protein toxin PT is a main virulence factor and consists of a binding subunit that facilitates transport of an enzyme subunit into the cytosol of target cells. There, the enzyme subunit ADP-ribosylates inhibitory α-subunits of G-protein coupled receptors resulting in disturbed cAMP signaling. As an important virulence factor associated with severe symptoms, such as leukocytosis, and poor outcomes, PT represents an attractive drug target to develop novel therapeutic strategies. In this review, chaperone inhibitors, human peptides, small molecule inhibitors, and humanized antibodies are discussed as novel strategies to inhibit PT.

Timing of SARS-CoV-2 vaccination during the third trimester of pregnancy and transplacental antibody transfer: a prospective cohort study

OBJECTIVE

We aimed to assess the impact of early versus late third-trimester maternal severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination on transplacental transfer and neonatal levels of SARS-CoV-2 antibodies.

METHODS

Maternal and cord blood sera were collected following term delivery after antenatal SARS-CoV-2 BNT162b2 mRNA vaccination, with the first vaccine dose administered between 27 and 36 weeks of gestation. SARS-CoV-2 spike protein (S) and receptor-binding domain (RBD) -specific, IgG levels and neutralizing potency were evaluated in maternal and cord blood samples.

RESULTS

The study cohort consisted of 171 parturients-median age 31 years (interquartile range (IQR) 27-35 years); median gestational age 39⁺⁵ weeks (IQR 38⁺⁵-40⁺⁴ weeks)-83 (48.5%) were immunized in early thrird-trimester (first dose at 27-31 weeks) and 88 (51.5%) were immunized in late third trimester (first dose at 32-36 weeks). All mother-infant paired sera were positive for anti S- and anti-RBD-specific IgG. Anti-RBD-specific IgG concentrations in neonatal sera were higher following early versus late third-trimester vaccination (median 9620 AU/mL (IQR 5131-15332 AU/mL) versus 6697 AU/mL (IQR 3157-14731 AU/mL), p 0.02), and were positively correlated with increasing time since vaccination (r = 0.26; p 0.001). Median antibody placental transfer ratios were increased following early versus late third-trimester immunization (anti-S ratio: 1.3 (IQR 1.1-1.6) versus 0.9 (IQR 0.6-1.1); anti-RBD-specific ratio: 2.3 (IQR 1.7-3.0) versus 0.7 (IQR 0.5-1.2), p < 0.001). Neutralizing antibodies placental transfer ratio was greater following early versus late third-trimester immunization (median 1.9 (IQR 1.7-2.5) versus 0.8 (IQR 0.5-1.1), p < 0.001), and was positively associated with longer duration from vaccination (r = 0.77; p < 0.001).

CONCLUSIONS

Early compared with late third-trimester maternal SARS-CoV-2 immunization enhanced transplacental antibody transfer and increased neonatal neutralizing antibody levels. Our findings highlight that vaccination of pregnant women early in the third trimester may enhance neonatal seroprotection.

Breastfeeding in the context of the COVID-19 pandemic: A discussion paper

Breastfeeding offers one of the most fundamental global health benefits for babies. Breastmilk is lifesaving, providing not only nutrition but immunologic benefits and as such is strongly supported by the World Health Organization and leading healthcare associations worldwide. When the COVID-19 pandemic started in 2020, the impact of the restrictions to prevent the spread of the disease created challenges and questions about provision of safe, quality care, including breastfeeding practices, in a new 'normal' environment. Mothers were temporarily separated from their babies where infection was present or suspected, parents were prevented from being present on neonatal units and vital breastfeeding support was prevented. This discussion paper provides an overview of essential areas of knowledge related to practice for neonatal nurses and midwives who care for breastfeeding mothers and babies, in the context of the COVID-19 pandemic and the latest global guidance. Three areas will be discussed; the protective benefits of breastfeeding, keeping breastfeeding mothers and babies together and supporting mothers to breastfeed their babies. Finally, care recommendations are presented to serve as a summary of key points for application to practice for neonatal nurses and midwives.

Suboptimal Vaccination Administration in Mothers With Inflammatory Bowel Disease and Their Biologic-Exposed Infants

BACKGROUND

Pregnant women with inflammatory bowel disease (IBD) are at increased risk of developing complications from vaccine-preventable infections. We investigated the factors influencing vaccine administration in pregnant women with IBD and their infants, in addition to the safety of vaccination in the infants.

METHODS

This retrospective cohort study identified individuals from a tertiary referral clinic whose records were linked to a provincial vaccine database. We conducted χ 2 tests, Fisher exact tests, and logistic regression adjusting for age and disease duration to compare vaccine administration by medication class. Potential rotavirus vaccine adverse events were determined in infants of women with IBD.

RESULTS

We included 303 pregnant women and 262 infants. Vaccines were administered to women on biologic therapy as follows: hepatitis B virus (82.9%), diphtheria-tetanus-pertussis (82.1%), and hepatitis A virus (49.3%). The influenza vaccination was provided peripartum in 50.7% of patients. The measles-mumps-rubella-varicella vaccine was provided to 89.3% of women before biologic initiation. Women treated with a biologic (adjusted odds ratio, 2.50; 95% confidence interval, 1.39-4.35) or immunomodulator (adjusted odds ratio, 4.00; 95% confidence interval, 2.22-7.69) were more likely to receive the Prevnar 13 and Pneumovax 23 vaccines than were unexposed individuals, but the overall proportion vaccinated was low (Prevnar 13, 35.7%; Pneumovax 23, 39.3%). At least 90% of infants received the measles-mumps-rubella-varicella vaccine and inactivated vaccines. Fourteen biologic-exposed children (19.2%) received the live rotavirus vaccine with no significant differences in adverse events compared with biologic-unexposed infants (7.1% vs 8.2%, P = 0.99).

CONCLUSIONS

Better education surrounding vaccine recommendations is required for both health care providers and individuals with IBD given poor pneumococcal, hepatitis A virus, and influenza vaccination rates. Inadvertent administration of the rotavirus vaccine in biologic-exposed infants did not result in more adverse events, raising the possibility of safety.

Factors Impacting Vaccine Uptake during Pregnancy: A Retrospective Analysis

BACKGROUND AND OBJECTIVE

Vaccine uptake rates during pregnancy remain below target goals due to a convergence of factors. In particular, women of lower socioeconomic means and racial minorities typically have reduced rates of vaccine acceptance. This study aims to identify additional factors contributing to vaccine acceptance within a sample population of women receiving prenatal care in Houston, Texas, United States of America.

METHODS

We performed a retrospective cross-sectional analysis of 11,500 pregnant women covered by Medicaid or ChipPerinate who received prenatal care during 2013-2021, assessing influenza (flu) and combined Tetanus, Diphtheria, Acellular Pertussis (TDAP) vaccine acceptance in the patient population. We examined temporal trends in flu and TDAP vaccination rates using Joinpoint regression analyses and evaluated the factors associated with single or concomitant vaccine acceptance during the study period and during the COVID-19 pandemic using adjusted log-binomial regression models.

RESULTS

In our population, 54% of patients received flu vaccination, and 76.1% received TDAP. TDAP rates increased from 2013-2015 but have shown an overall decline since then, as with the flu vaccine. Earlier entry to prenatal care (Prevalence Ratio [PR] 6.32; Confidence Interval [CI] 3.28-12.24) and pregnancy comorbidity such as gestational diabetes (PR 1.32; CI 0.82-2.19) were positively associated with uptake. In contrast, the NH-Black race was negatively associated with vaccine acceptance (PR 0.51 CI; 0.25-0.99). Otherwise, age and history of pre-pregnancy comorbidities were not significant predictors.

CONCLUSION AND GLOBAL HEALTH IMPLICATIONS

Within demographic groups identified as at-risk for vaccine refusal, modifying factors further impact vaccine hesitancy. Identifying these elements will guide targeted patient efforts to promote vaccine uptake, both for routine prenatal recommendations and for COVID vaccination.

Programme costs for introducing age/gestation-based universal influenza vaccine schedules for young children and pregnant women in Hong Kong

BACKGROUND

Hong Kong experiences year-round influenza activity with winter and summer peaks. The government's Vaccination Subsidy Scheme (VSS) provides vaccine to high-risk groups prior to the larger winter peak. The VSS is predominantly administered through the private sector. This study aimed to cost the two theoretical routine influenza vaccination schedules using both northern and southern hemisphere vaccines, administered according to child's age and women's gestation, from a governmental perspective; and compare these costs to the costs of government's seasonal VSS assuming equivalent coverage estimates to determine the budget impacts of these influenza vaccination programmes in Hong Kong.

METHODS

We used the World Health Organization's Flutool Plus to estimate the incremental annual costs for immunising young children aged 6 months to 2 years and pregnant women with influenza vaccine during 2021, assuming the latter group accesses the public system for some antenatal care. Inputs were based on literature review, publicly available data and expert opinions. Sensitivity analyses were done with various coverage rates and vaccine costs.

RESULTS

The annual incremental cost (including vaccine price) to vaccinate young children with three doses of influenza vaccine during the first two years of life was estimated at USD 1,175,146 (per-dose-cost of USD 10.55) at 75% coverage while that to vaccinate pregnant women with one dose at 60% coverage was estimated at USD 398,555 (per-dose-cost of USD 13.39). Across a range of sensitivity analyses we predict that routine year-round schedules could be cost-saving to the government compared to the VSS. Implementing routine immunisation to both risk groups equates to USD 1,573,701, i.e., 0.012% of Hong Kong's annual healthcare spending.

CONCLUSION

Proposed year-round universal schedules providing influenza immunisation according to the child's age or the woman's gestation are predicted to be cost-saving compared to the current seasonally administered subsidised vaccine programme.

Transplacental Antibody Transfer of Respiratory Syncytial Virus Specific IgG in Non-Human Primate Mother-Infant Pairs

One approach to protect new-borns against respiratory syncytial virus (RSV) is to vaccinate pregnant women in the last trimester of pregnancy. The boosting of circulating antibodies which can be transferred to the foetus would offer immune protection against the virus and ultimately the disease. Since non-human primates (NHPs) have similar reproductive anatomy, physiology, and antibody architecture and kinetics to humans, we utilized this preclinical species to evaluate maternal immunization (MI) using an RSV F subunit vaccine. Three species of NHPs known for their ability to be infected with human RSV in experimental challenge studies were tested for RSV-specific antibodies. African green monkeys had the highest overall antibody levels of the old-world monkeys evaluated and they gave birth to offspring with anti-RSV titers that were proportional to their mother. These higher overall antibody levels are associated with greater durability found in their offspring. Immunization of RSV seropositive AGMs during late pregnancy boosts RSV titers, which consequentially results in significantly higher titers in the vaccinated new-borns compared to the new-borns of unvaccinated mothers. These findings, accomplished in small treatment group sizes, demonstrate a model that provides an efficient, resource sparing and translatable preclinical in vivo system for evaluating vaccine candidates for maternal immunization.

Recommendations of the Italian society for infectious and tropical diseases (SIMIT) for adult vaccinations

Vaccination prevents 2-3 million deaths worldwide every year. Nevertheless, vaccine-preventable diseases (VPDs) still cause a considerable number of deaths especially in subjects belonging to "risk groups." These are represented by older adults, immunocompromised individuals and all subjects with underlying chronic medical conditions (cardiovascular, pulmonary, renal and liver chronic diseases, diabetes, immunodeficiency disorders). They have a weaker immune system and, if infected, are more likely to develop severe complications of their condition or of the preventable-infectious disease. This document summarizes the recommendations for vaccination of the main Global Institutional Organizations and analyses the risks of comorbidities associated with infectious disease and the benefits of vaccination for each specific group. The document provides a clear, practical and authoritative guide to adult vaccination.

BNT162b2 Vaccination during Pregnancy Protects Both the Mother and Infant: Anti-SARS-CoV-2 S Antibodies Persistently Positive in an Infant at 6 Months of Age

Vaccinations are the most important intervention for controlling the ongoing coronavirus disease (COVID-19) pandemic, caused by the SARS-CoV-2 virus. BNT162b2 is an mRNA-based vaccine, which is promising and safe for use during pregnancy, as it could help prevent SARS-CoV-2 infection and its complications during pregnancy. Other vaccines, such as influenza and Tdap (tetanus toxoid, reduced diphtheria toxoid, and acellular pertussis) vaccines, provide significant protection for babies. Recent studies have shown that COVID-19 antibodies are present in newborns at birth, owing to maternal BNT162b2 vaccination during pregnancy; however, it is currently unclear how long these antibodies could protect infants from SARS-CoV-2 infection and its complications. Herein, we present the case of a preterm baby born at 33 weeks via an emergency cesarean section owing to maternal complications. The mother had received two doses of the BNT162b2 vaccine at 22 and 26 weeks of gestation. Positive anti-SARS-CoV-2 S antibodies were detected in the infant at 2 weeks, 6 weeks, 3 months, and 6 months of age. This is the first case report in which BNT162b2 vaccination during pregnancy yielded a persistent immune response in an infant at 6 months of age. The declining anti-SARS-CoV-2 S antibody titers noted at 6 months of age emphasize the need for the vaccination of children at this age.

Retrospective analysis of neonatal deaths secondary to infections in England and Wales, 2013-2015

OBJECTIVE

To estimate the overall and infection-related neonatal mortality rate and the pathogens responsible using electronic death registrations.

DESIGN

Retrospective analysis of national electronic death registrations data.

SETTING

England and Wales.

PATIENTS

Neonates aged <28 days.

MAIN OUTCOME MEASURES

Overall and infection-related mortality rate per 1000 live births in term, preterm (28-36 weeks) and extremely preterm (<28 weeks) neonates; the contribution of infections and specific pathogens; comparison with mortality rates in 2003-2005.

RESULTS

The neonatal mortality rate during 2013-2015 (2.4/1000 live births; 5095 deaths) was 31% lower than in 2003-2005 (3.5/1000; 6700 deaths). Infection-related neonatal mortality rate in 2013-2015 (0.32/1000; n=669) was 20% lower compared with 2003-2015 (0.40/1000; n=768), respectively. Infections were responsible for 13.1% (669/5095) of neonatal deaths during 2013-2015 and 11.5% (768/6700) during 2003-2005. Of the infection-related deaths, 44.2% (296/669) were in term, 19.9% (133/669) preterm and 35.9% (240/669) extremely preterm neonates. Compared with term infants (0.15/1000 live births), infection-related mortality rate was 5.9-fold (95% CI 4.7 to 7.2) higher in preterm (0.90/1000) and 188-fold (95% CI 157 to 223) higher in extremely preterm infants (28.7/1000) during 2013-2015. A pathogen was recorded in 448 (67%) registrations: 400 (89.3%) were bacterial, 37 (8.3%) viral and 11 (2.4%) fungal. Group B streptococcus (GBS) was reported in 30.4% (49/161) of records that specified a bacterial infection and 7.3% (49/669) of infection-related deaths.

CONCLUSIONS

Overall and infection-related neonatal mortality rates have declined, but the contribution of infection and of specific pathogens has not changed. Further preventive measures, including antenatal GBS vaccine may be required to prevent the single most common cause of infection-related deaths in neonates.

The Breast Milk Immunoglobulinome

Breast milk components contribute to the infant’s immune development and protection, and among other immune factors, immunoglobulins (Igs) are the most studied. The presence of IgA in milk has been known for a long time; however, less information is available about the presence of other Igs such as IgM, IgG, and their subtypes (IgG1, IgG2, IgG3, and IgG4) or even IgE or IgD. The total Ig concentration and profile will change during the course of lactation; however, there is a great variability among studies due to several variables that limit establishing a clear pattern. In this context, the aim of this review was firstly to shed light on the Ig concentration in breast milk based on scientific evidence and secondly to study the main factors contributing to such variability. A search strategy provided only 75 studies with the prespecified eligibility criteria. The concentrations and proportions found have been established based on the intrinsic factors of the study—such as the sampling time and quantification technique—as well as participant-dependent factors, such as lifestyle and environment. All these factors contribute to the variability of the immunoglobulinome described in the literature and should be carefully addressed for further well-designed studies and data interpretation.

Maternal Vaccination in Uganda: Exploring Pregnant Women, Community Leaders and Healthcare Workers' Perceptions

Background: We investigated pregnant women, community leaders, healthcare workers (HCWs) and programme managers' perceptions of maternal vaccination in Kampala, Uganda. Methods: We conducted focus group discussions, key informant interviews and in-depth discussions with HCWs (3), community leaders (3), pregnant women (8) and programme managers (10) between November 2019 and October 2020. Data were analysed thematically. Results: Pregnant women, community leaders and some HCWs had limited maternal immunisation knowledge. There was confusion over what constitutes a vaccine. Pregnant women may not receive vaccines because of mistrust of government; use of expired vaccines; reliance on traditional medicine; religious beliefs; fear of side effects; HCWs attitudes; and logistical issues. The key facilitators of maternal vaccination were a desire to prevent diseases, positive influences from HCWs and information about vaccine side effects. Community leaders and some pregnant women highlighted that pregnant women do not make decisions about maternal vaccination independently and are influenced by different individuals, including other pregnant women, older people, partners, relatives (parents), community leaders, HCWs and the government. Conclusions: Our results indicate that public health messaging should target all community members, including partners and parents of pregnant women as well as HCWs, to improve knowledge of and confidence in maternal vaccines.

The Path to New Pediatric Vaccines against Pertussis

Whooping cough, or pertussis, mostly caused by Bordetella pertussis, is a respiratory disease that affects all age groups, but severe and fatal pertussis occurs almost exclusively in young children. The widespread use of whole-cell and, more recently, of acellular vaccines has substantially reduced the disease incidence. However, it has not been eliminated in any part of the world and has made a worrisome rebound in several areas. Cocoon and maternal immunization have been implemented in several countries but have their intrinsic limitations. To effectively control pertussis, novel vaccines are needed that protect against disease and prevent B. pertussis infection and transmission, which is not the case for current vaccines. Several approaches are contemplated, including alternative administration routes, such as nasal immunization, improvement of acellular vaccines by adding more antigens and T-cell-promoting adjuvants, and the development of novel vaccines, such as outer membrane vesicles and live attenuated vaccines. Among them, only a live attenuated vaccine has so far been assessed for safety and immunogenicity in preclinical models other than mice and is in clinical development. Before any of these vaccines can be used in neonates, extensive safety and immunogenicity assessment in pre-clinical neonatal models and in carefully designed clinical trials is necessary. The aim of this review is to discuss the current pertussis problem, implemented strategies to resolve it, the value of animal models and novel vaccine approaches.

Protection of the Newborn Through Vaccination in Pregnancy

Newborns and infants are at risk for severe infections with some pathogens (eg, Bordetella pertussis, influenza, respiratory syncytial virus, group B Streptococcus) during early life. To decrease this window of high susceptibility to some infections during early life and protect young infants, vaccination in pregnancy against some vaccine-preventable diseases (eg, influenza, pertussis, tetanus) has been recommended in an increasing number of countries with notable success. In addition, recent advances have been made in developing vaccines for pregnant women with the aim of reducing the respiratory syncytial virus and group B Streptococcus burden in infancy. In this article, we review the vaccines currently recommended during pregnancy and their benefits to newborns and infants. We also discuss progress made in the development of other vaccines that are expected to be evaluated in pregnant women in the near future.

Levels of antibodies specific to diphtheria toxoid, tetanus toxoid, and Haemophilus influenzae type b in healthy children born to Tdap-vaccinated mothers

INTRODUCTION

Vaccination of pregnant women protects both women and their newborns against some infectious diseases. Thailand implemented tetanus toxoid (TT) vaccination of pregnant women in 1977, which was replaced by tetanus-diphtheria toxoid (dT) vaccination in 2005. The tetanus-diphtheria-acellular pertussis (Tdap) vaccine has been recommended for pregnant women at 27-36 weeks of gestation since 2012 in several countries. Data on antibody responses to diphtheria toxoid (DT), TT, and Hemophilus influenzae type b (Hib) induced by combined vaccines in children born to TT-vaccinated and/or Tdap-vaccinated mothers are limited.

MATERIAL AND METHODS

We investigated anti-DT, anti-TT, and anti-Hib IgG responses in a cohort of Thai children (ClinicalTrial.gov NCT02408926) born to mothers who received a TT-containing and/or the Tdap vaccine during pregnancy. Children born to Tdap-vaccinated mothers were randomized to receive either a hexavalent (Infanrix-hexa) or pentavalent (Quinvaxem) vaccine, whereas children born to TT-vaccinated mothers received only Quinvaxem vaccine at 2, 4, 6, and 18 months of age. IgG levels were evaluated at birth (cord blood), 2 (pre-primary), 7 (post-primary), 18 (pre-booster), and 19 months of age (post-booster) using a commercially available enzyme-linked immunoassay.

RESULTS

Seroprotective concentrations of anti-DT, anti-TT, and anti-Hib IgG were achieved in >90% and >99% of children following primary and booster vaccination, respectively. Among children born to Tdap-vaccinated mothers, the pentavalent vaccine induced higher levels of anti-Hib IgG than the hexavalent vaccine after primary and booster vaccination. Significantly higher anti-Hib IgG levels were observed among children receiving the pentavalent vaccine and who were born to TT-vaccinated mothers than among children receiving the pentavalent vaccine and born to Tdap-vaccinated mothers after primary and booster vaccination.

CONCLUSIONS

Vaccination with a TT-containing and/or the Tdap vaccine during pregnancy did not compromise the seroprotection rate achieved following primary and booster immunization in individuals receiving either the pentavalent or hexavalent vaccine.

Preventive Allergen-Specific Vaccination Against Allergy: Mission Possible?

Vaccines for infectious diseases have improved the life of the human species in a tremendous manner. The principle of vaccination is to establish de novo adaptive immune response consisting of antibody and T cell responses against pathogens which should defend the vaccinated person against future challenge with the culprit pathogen. The situation is completely different for immunoglobulin E (IgE)-associated allergy, an immunologically-mediated hypersensitivity which is already characterized by increased IgE antibody levels and T cell responses against per se innocuous antigens (i.e., allergens). Thus, allergic patients suffer from a deviated hyper-immunity against allergens leading to inflammation upon allergen contact. Paradoxically, vaccination with allergens, termed allergen-specific immunotherapy (AIT), induces a counter immune response based on the production of high levels of allergen-specific IgG antibodies and alterations of the adaptive cellular response, which reduce allergen-induced symptoms of allergic inflammation. AIT was even shown to prevent the progression of mild to severe forms of allergy. Consequently, AIT can be considered as a form of therapeutic vaccination. In this article we describe a strategy and possible road map for the use of an AIT approach for prophylactic vaccination against allergy which is based on new molecular allergy vaccines. This road map includes the use of AIT for secondary preventive vaccination to stop the progression of clinically silent allergic sensitization toward symptomatic allergy and ultimately the prevention of allergic sensitization by maternal vaccination and/or early primary preventive vaccination of children. Prophylactic allergy vaccination with molecular allergy vaccines may allow halting the allergy epidemics affecting almost 30% of the population as it has been achieved for vaccination against infectious diseases.

Influenza Vaccination Experiences of Pregnant Women as a Predictor of the Intention to Become Vaccinated in Future Pregnancies in Spain

A good perception of the vaccines administered during pregnancy favors immunization coverage, which is still not optimal for the influenza vaccine. To understand the predisposition towards vaccination in future pregnancies, a study was performed that evaluated the experiences of women with the vaccine or influenza. A cross-sectional study was conducted through telephone interviews given to a total of 683 postpartum women in two health departments from the Valencia Community (Spain). This interview asked about their intention of becoming vaccinated in future pregnancies and whether they were favor or against vaccination. Most of them, 98.5% (n = 673 [95% CI: 97.6–99.4]) (p < 0.001) declared having received the systematic vaccines throughout their lives. The ones who were vaccinated against influenza, 91.9% (n = 387 [95% CI: 89.2–94.6]) (p < 0.001) manifested they would do so in future pregnancies. The probability of future non-vaccination was modeled, which was related to an unfavorable opinion towards vaccines (OR = 4.07 [95% CI: 2.01–8.24]) (p < 0.001), having suffered from influenza during pregnancy (OR = 3.84 [95% CI: 1.41–10.42]) (p < 0.05), and not having been vaccinated during previous pregnancies (OR = 38.47 [95% CI: 23.58–62.76]) (p < 0.001). Vaccination during pregnancy increases the intent of vaccination in the future.