Maternal Immunization: Nature Meets Nurture.

Anja Saso,Beate Kampmann

doi:10.3389/fmicb.2020.01499

Anja Saso, Beate Kampmann

Open Access

https://doi.org/10.3389/fmicb.2020.01499

Copy DOI

Abstract

Vaccinating women in pregnancy (i.e., maternal immunization) has emerged as a promising tool to tackle infant morbidity and mortality worldwide. This approach nurtures a ‘gift of nature,’ whereby antibody is transferred from mother to fetus transplacentally during pregnancy, or postnatally in breast milk, thereby providing passive, antigen-specific protection against infections in the first few months of life, a period of increased immune vulnerability for the infant. In this review, we briefly summarize the rationale for maternal immunization programs and the landscape of vaccines currently in use or in the pipeline. We then direct the focus to the underlying biological phenomena, including the main mechanisms by which maternally derived antibody is transferred efficiently to the infant, at the placental interface or in breast milk; important research models and methodological approaches to interrogate these processes, particularly in the context of recent advances in systems vaccinology; the potential biological and clinical impact of high maternal antibody titres on neonatal ontogeny and subsequent infant vaccine responses; and key vaccine- and host-related factors influencing the maternal-infant dyad across different environments. Finally, we outline important gaps in knowledge and suggest future avenues of research on this topic, proposing potential strategies to ensure optimal testing, delivery and implementation of maternal vaccination programs worldwide.

Highlights

To improve maternal and neonatal health remains a focus of international investment in global health, given that Millenium Goals 4 and 5 were not achieved (Victora et al, 2016)
Despite the wider roll-out and availability of vaccines through the Expanded Program of Immunization (EPI) and their significant contribution to the reduction in under-5 morbidity and mortality, there remains a large gap in protection from infectious diseases in newborns: 40% of all mortality in children under the age of 5 falls into the neonatal period, a third is attributable to potentially preventable infections
There is increasing momentum to develop and implement vaccination of women during pregnancy to prevent specific infections of particular relevance to pregnancy and the newborn (Zaman et al, 2008; Lindsey et al, 2012; Saso and Kampmann, 2016; Switzer et al, 2019). This approach nurtures a ‘gift of nature,’ whereby antibody is transferred from mother to fetus during pregnancy, via the placenta or postnatally in breast milk, in order to provide passive protection against pathogens in the first few months of life

Summary

INTRODUCTION

To improve maternal and neonatal health remains a focus of international investment in global health, given that Millenium Goals 4 and 5 were not achieved (Victora et al, 2016). Comparisons between HIV-infected and -uninfected women in different settings have shown that the former group have lower baseline/pre-vaccination protective maternal antibody levels to key vaccine pathogens and impaired transplacental transfer of IgG; this includes tetanus, GBS, VZV, measles, Hib, pertussis, and pneumococcus antibodies, it is not a universal finding (Isabel de Moraes-Pinto et al, 1996; Cumberland et al, 2007; Jones et al, 2011, 2013; Gupta et al, 2014; Dangor et al, 2015; Le Doare et al, 2015) This may be explained by a loss of epitope-specific T- and B-memory cells secondary to immunosuppressive progression of HIV-infection (Wheatley et al, 2016; Dangor et al, 2017). Recent initiatives and multi-stakeholder involvement are beginning to turn the tide

Methodology

Findings

CONCLUSION