The Safety of PsA-TT in Pregnancy: An Assessment Performed Within the Navrongo Health and Demographic Surveillance Site in Ghana

Defining and reporting adverse events of special interest in comparative maternal vaccine studies: a systematic review

Introduction

The GAIA (Global Alignment on Immunisation Safety Assessment in Pregnancy) consortium was established in 2014 with the aim of creating a standardised, globally coordinated approach to monitoring the safety of vaccines administered in pregnancy. The consortium developed twenty-six standardised definitions for classifying obstetric and infant adverse events. This systematic review sought to evaluate the current state of adverse event reporting in maternal vaccine trials following the publication of the case definitions by GAIA, and the extent to which these case definitions have been adopted in maternal vaccine safety research.

Methods

A comprehensive search of published literature was undertaken to identify maternal vaccine research studies. PubMed, EMBASE, Web of Science, and Cochrane were searched using a combination of MeSH terms and keyword searches to identify observational or interventional studies that examined vaccine safety in pregnant women with a comparator group. A two-reviewer screening process was undertaken, and a narrative synthesis of the results presented.

Results

14,737 titles were identified from database searches, 435 titles were selected as potentially relevant, 256 were excluded, the remaining 116 papers were included. Influenza vaccine was the most studied (25.0%), followed by TDaP (20.7%) and SARS-CoV-2 (12.9%).Ninety-one studies (78.4%) were conducted in high-income settings. Forty-eight (41.4%) utilised electronic health-records. The majority focused on reporting adverse events of special interest (AESI) in pregnancy (65.0%) alone or in addition to reactogenicity (27.6%). The most frequently reported AESI were preterm birth, small for gestational age and hypertensive disorders. Fewer than 10 studies reported use of GAIA definitions. Gestational age assessment was poorly described; of 39 studies reporting stillbirths 30.8% provided no description of the gestational age threshold.

Conclusions

Low-income settings remain under-represented in comparative maternal vaccine safety research. There has been poor uptake of GAIA case definitions. A lack of harmonisation and standardisation persists limiting comparability of the generated safety data.

Preventing invasive meningococcal disease in early infancy

This review considers the pathogenesis, diagnosis, and epidemiology of invasive meningococcal disease in infants, to examine and critique meningococcal disease prevention in this population through vaccination. High rates of meningococcal disease and poor outcomes, particularly for very young infants, highlight the importance of meningococcal vaccination in early infancy. Although effective and safe meningococcal vaccines are available for use from 6 weeks of age, they are not recommended globally. Emerging real-world data from the increased incorporation of these vaccines within immunization programs inform recommendations regarding effectiveness, appropriate vaccination schedule, possible long-term safety effects, and persistence of antibody responses. Importantly, to protect infants from IMD, national vaccination recommendations should be consistent with available data regarding vaccine safety, effectiveness, and disease risk.

Maternal vaccination: a review of current evidence and recommendations

Maternal vaccination is an effective means of protecting pregnant women, their fetuses, and infants from vaccine-preventable infections. Despite the availability of sufficient safety data to support the use of vaccines during pregnancy, maternal immunization remains an underutilized method of disease prevention, often because of concerns from both healthcare providers and pregnant women about vaccine safety. Such concerns have been reflected in the low uptake of the COVID-19 vaccine among pregnant women seen in many parts of the world. Here, we present an update of the current recommendations for the use of vaccines during pregnancy, including the evidence supporting the use of novel vaccine platforms. We also provide an overview of the data supporting the use of COVID-19 vaccines in pregnancy and an update of the status of vaccines that are currently under development for use in pregnant women.

Are all vaccines safe for the pregnant traveller? A systematic review and meta-analysis

Pregnant travellers and their offspring are vulnerable to severe outcomes following a wide range of infections. Vaccine-preventable diseases can have a particularly severe course in pregnant women, but little is known about the safety of travel vaccines in pregnant women. We performed a systematic review of all published literature concerning the safety of vaccines frequently given to travellers such as yellow fever, MMR (mumps, measles and rubella), influenza, Tdap (tetanus, diphtheria and pertussis), meningococcus, hepatitis A and B, rabies, polio, typhoid fever, tick-borne encephalitis and Japanese encephalitis vaccines. We included case series, cohort studies and randomized controlled trials (RCTs). For the meta-analysis, we included only RCTs that compared the administration of a vaccine to placebo or to no vaccine. Outcome measures included severe systemic adverse events, maternal outcomes related to the course of pregnancy, neonatal outcomes and local adverse events. We calculated the risk ratio and its 95% confidence interval as the summary measure. The safety of influenza vaccine is supported by high-quality evidence. For Tdap vaccine, no evidence of any harm was found in the meta-analysis of RCTs. A slight increase in chorioamnionitis rate was reported in 3 out of 12 observational studies. However, this small possible risk is far outweighed by a much larger benefit in terms of infant morbidity and mortality. Meningococcal vaccines are probably safe during pregnancy, as supported by RCTs comparing meningococcal vaccines to other vaccines. Data from observational studies support the safety of hepatitis A, hepatitis B and rabies vaccines, as well as that of the live attenuated yellow fever vaccine. We found little or no data about the safety of polio, typhoid, Japanese encephalitis, tick-borne encephalitis and MMR vaccines during pregnancy.

Maternal immunisation to improve the health of HIV-exposed infants

HIV-exposed but uninfected (HEU) infants are at an increased risk of many infectious diseases that can contribute to the high mortality seen among HEU children. Maternal immunisation could be a promising strategy to reduce infections in HEU infants. However, very little research has explored the effect of HIV on the immunogenicity and effectiveness of vaccines given during pregnancy. We review the available evidence on maternal immunisation among women living with HIV (WLWH) for all vaccines recommended, considered, or being investigated for routine or risk-based use during pregnancy. Of the 11 vaccines included, only three have been investigated in WLWH. Available evidence suggests that maternal HIV infection limits the immunogenicity of several vaccines, leaving HEU infants more susceptible to infection during their first few months of life. Whether maternal immunisation reduces the infectious morbidity and mortality associated with infectious diseases in HEU children remains unknown. We conclude the Review by identifying future research priorities.

Mapping the landscape of global programmes to evaluate health interventions in pregnancy: the need for harmonised approaches, standards and tools

Pregnant women and their babies are among the populations most vulnerable to untoward health outcomes. Yet current standards for evaluating health interventions cannot be met during pregnancy because of lack of adequate evidence. The situation is even more concerning in low-income and middle-income countries, where the need for effective interventions is the greatest. Meeting the Sustainable Development Goals for health will require strengthened attention to maternal and child health. In this paper we examine ongoing initiatives aimed at improving the assessment of maternal interventions. We review current methodologies to monitor outcomes of maternal interventions and identify where harmonisation is needed. Based on this analysis we identify settings where different minimal data sets should be considered taking into consideration the clinical realities. Stronger coordination mechanisms and a roadmap to support harmonised monitoring of maternal interventions across programmes and partners, working on improving pregnancy and early childhood health events, will greatly enhance ability to generate evidence-based policies.

Maternal immunization

Pregnant women, neonates, and infants are at higher risk for severe infections due to vaccine-preventable diseases. Very young infants rarely respond well to vaccination due to poor immunogenicity and interference from maternal antibody. Maternal immunization protects the mother and fetus from disease and protects the infant through transplacental antibody transfer through the first 6 months of life. Currently, immunizations routinely recommended during pregnancy include inactivated influenza, tetanus toxoid, and acellular pertussis vaccines. Promising maternal vaccine candidates in development include a group B streptococcus vaccine and a respiratory syncytial virus vaccine. Birth Defects Research 109:379-386, 2017. © 2017 Wiley Periodicals, Inc.

Meningococcal vaccination in pregnancy

Invasive meningococcal disease causes meningitis and septicemia worldwide with highest rates of disease occurring in children <2 years of age, and in particular young infants. Vaccination during pregnancy has been a successful strategy for prevention of other infections in young infants, most notably tetanus, pertussis and influenza. However, few studies of meningococcal vaccines in pregnancy have been undertaken, and none include the most commonly used current vaccines to prevent disease by capsular groups A, B, C, W and Y. The limited data suggest that the older polysaccharide vaccines are immunogenic, but the impact on prevention of infant disease has not been measured. Further studies of MenB protein vaccines and MenA protein-polysaccharide conjugate vaccines in particular are needed if vaccination in pregnancy is to be utilized as an approach to prevention of meningococcal disease in young infants.

Who's the Target: Mother or Baby?

Maternal immunization for prevention of morbidity and mortality of pregnant women and their neonates due to infectious diseases is ongoing worldwide. The complexity of vaccine research and development in this population is challenging. Not only do vaccines for pregnant women require evidence of immunogenicity, potency, stability, and limited reactogenicity, they must also provide efficacy in decreasing morbidity for the pregnant woman, her fetus, and the neonate, demonstrate safety or lack of evidence of harm, and offer benefit or potential benefit of vaccination during pregnancy. Since the 19th century, evidence of protective effects of vaccination during pregnancy has been documented. Pandemic influenza and pertussis outbreaks in recent years have affected a paradigm shift in vaccine research and development as well as current policy regarding immunization in pregnancy. Studies of the immune system in pregnant women and neonates have shown that immune changes associated with pregnancy in women do not interfere with maternal vaccine responses, multiple factors are important in transplacental transfer of antibodies, and maternal antibodies are beneficial to neonates. In recent years, guidelines have been developed by expert panels to help design studies for maternal vaccinations and for harmonization of data collection, analysis, and adverse event reporting. Further research into maternal and neonatal immunology, transplacental antibody transfer, and epidemiology of diseases is needed, especially as new vaccines to respiratory syncytial virus, cytomegalovirus, and Group B streptococcus are developed. Maternal vaccinations have the potential to change the epidemiology of infectious diseases in reproductive health and pediatrics and may lead to new clinical applications to improve global maternal and neonatal health.

Meningococcal disease in the Asia-Pacific region: Findings and recommendations from the Global Meningococcal Initiative

The Global Meningococcal Initiative (GMI) is a global expert group that includes scientists, clinicians, and public health officials with a wide range of specialties. The purpose of the Initiative is to promote the global prevention of meningococcal disease (MD) through education, research, and cooperation. The first Asia-Pacific regional meeting was held in November 2014. The GMI reviewed the epidemiology of MD, surveillance, and prevention strategies, and outbreak control practices from participating countries in the Asia-Pacific region.Although, in general, MD is underreported in this region, serogroup A disease is most prominent in low-income countries such as India and the Philippines, while Taiwan, Japan, and Korea reported disease from serogroups C, W, and Y. China has a mixed epidemiology of serogroups A, B, C, and W. Perspectives from countries outside of the region were also provided to provide insight into lessons learnt. Based on the available data and meeting discussions, a number of challenges and data gaps were identified and, as a consequence, several recommendations were formulated: strengthen surveillance; improve diagnosis, typing and case reporting; standardize case definitions; develop guidelines for outbreak management; and promote awareness of MD among healthcare professionals, public health officials, and the general public.

Group B Streptococcus vaccine development: present status and future considerations, with emphasis on perspectives for low and middle income countries

Globally, group B Streptococcus (GBS) remains the leading cause of sepsis and meningitis in young infants, with its greatest burden in the first 90 days of life. Intrapartum antibiotic prophylaxis (IAP) for women at risk of transmitting GBS to their newborns has been effective in reducing, but not eliminating, the young infant GBS disease burden in many high income countries. However, identification of women at risk and administration of IAP is very difficult in many low and middle income country (LMIC) settings, and is not possible for home deliveries. Immunization of pregnant women with a GBS vaccine represents an alternate pathway to protecting newborns from GBS disease, through the transplacental antibody transfer to the fetus in utero. This approach to prevent GBS disease in young infants is currently under development, and is approaching late stage clinical evaluation. This manuscript includes a review of the natural history of the disease, global disease burden estimates, diagnosis and existing control options in different settings, the biological rationale for a vaccine including previous supportive studies, analysis of current candidates in development, possible correlates of protection and current status of immunogenicity assays. Future potential vaccine development pathways to licensure and use in LMICs, trial design and implementation options are discussed, with the objective to provide a basis for reflection, rather than recommendations.

Safety Monitoring in Group A Meningococcal Conjugate Vaccine Trials: Description, Challenges, and Lessons

BACKGROUND

The determination of the safety profile of any vaccine is critical to its widespread use in any population. In addition, the application of international guidelines to fit local context could be a challenging but important step toward obtaining quality safety data.

METHODS

In clinical studies of PsA-TT (MenAfriVac), safety was monitored immediately after vaccination, at 4-7 days for postimmunization local and systemic reactions, within 28 days for adverse events, and throughout the duration of study for serious adverse events. Initial and ongoing training of sites' staff were undertaken during the studies, and a data and safety monitoring board reviewed all the data during and after the studies.

RESULTS

The safety of PsA-TT was evaluated according to international standards despite obvious challenges in remote areas where these studies were conducted. These challenges included the need for uniformity of methods, timely reporting in the context of frequent communication problems, occurrence of seasonal diseases such as malaria and rotavirus diarrhea, and healthcare systems that required improvement.

CONCLUSIONS

The trials of PsA-TT highlighted the value of a robust vaccine development plan and design so that lessons learned in initial studies were incorporated into the subsequent ones, initial training and periodic retraining, strict monitoring of all procedures, and continuous channel of communication with all stakeholders that enabled the application of international requirements to local settings, with high quality of data.