Maternal Immunization

Elke Leuridan,Marta Nunes,Chrissie Jones

• Éditeur: Academic Press
• Année: 2019
• ISBN:
  9780128145838
• Sujet: Medicine
• Sous-sujet: Immunology

Immunization during pregnancy with currently recommended vaccines prevents infection in the mother, the unborn fetus, and the young infant, and there is an increasing focus from different stakeholders to use this approach for other infections of importance to protect these vulnerable groups. The aim of this Maternal Immunization book is to provide a contemporary overview of vaccines used in pregnancy (and the lactation period), with emphasis on aspects of importance for the target groups, namely, rationale for the use of vaccines in pregnancy, safety, immunogenicity (immunology), timing to vaccinate, repeat doses, protective effects in the mother, fetus, and infant, and public acceptance and implementation, of existing and of future vaccines.

• Provides an overview of a quickly evolving topic. This will benefit the reader who wishes to rapidly become informed and up-to-date with new developments in this field
• Suitable to a broad audience: scientific researchers, obstetricians, gynecologists, neonatologists, vaccinators, pediatricians, students, and industry. Maternal vaccination impacts a wide range of specialists
• Allows health care professionals/researchers to gain insight into other aspects of vaccination in pregnancy outside of their specialism
• Is coauthored by specialists from multiple disciplines, providing a diverse view of the subject, increasing its interest and appeal
• Creates awareness of the current developments in this area of medicine and of the potential of maternal vaccination to improve the health of mothers and infants worldwide

Part I

Concepts of maternal immunization

Chapter 1

The history of maternal immunization

Alisa Kachikis^a; Linda O. Eckert^a,b; Janet A. Englund^{c a} Department of Obstetrics and Gynecology, University of Washington, Seattle, WA, United States
^b Department of Global Health, University of Washington, Seattle, WA, United States
^c Department of Pediatrics, Pediatric Infectious Diseases, Seattle Children’s Hospital, University of Washington, Seattle, WA, United States

Abstract

Maternal immunization, or the vaccination of pregnant women for prevention of maternal, fetal and neonatal morbidity and mortality, has emerged as an exciting and rapidly expanding area of vaccine-preventable diseases research and clinical practice. The functionality of the maternal and neonatal immune system, transplacental transfer of antibodies to the fetus and potential inhibition of subsequent active infant immunization have added an additional layer of complexity to vaccine research. Today, vaccines are utilized in pregnant women to protect women and infants against influenza and pertussis, and additional vaccines are in development specifically for use in maternal immunization such as those against respiratory syncytial virus (RSV) and Group B Streptococcus (GBS). The current expanding applications of vaccines administered during pregnancy closely mirrors trends in public policy regarding research in pregnant women. Consideration of past lessons learned, current work in vaccinology, as well as policy regarding inclusion of reproductive age and pregnant women in research may better predict future directions and successes for this approach to the protection of women and infants.

Keywords

Maternal immunization; Vaccination in women; History of vaccines; Pregnancy; Vaccines; Group B Streptococcus; Respiratory syncytial virus; Influenza vaccines; Pertussis vaccines

Acknowledgments

We would like to express our gratitude to Jan Hamanishi for her help in designing Fig. 1 for this article.

Conflict of interest

AK and LOE have no financial conflicts to disclose. JAE has received research support to her institution from GlaxoSmithKline, Gilead, MedImmune, Novavax, and Chimerix. She has served as a consultant for Sanofi Pasteur and Gilead.

Introduction

Maternal immunization, or the vaccination of pregnant women, for prevention of maternal, fetal and neonatal morbidity and mortality, has emerged as an exciting and rapidly expanding area of vaccine-preventable diseases research and clinical practice in the last decades. The intricacies of the maternal and neonatal immune system, the transplacental transfer of antibodies to the fetus and potential inhibition of subsequent active infant immunization have added an additional layer of complexity to vaccine research. Nevertheless, vaccines are currently in development specifically for use in maternal immunization such as those against respiratory syncytial virus (RSV) and Group B Streptococcus (GBS) [1]. While maternal immunization strategies are not a new phenomenon and have a history similar to vaccine strategies overall, their current expanding application more closely mirrors trends in public policy regarding research in pregnancy. Consideration of past lessons learned, current work in vaccinology, as well as policy regarding inclusion of reproductive age and pregnant women in research may better predict future directions and successes for immunization in pregnancy.

The need from a historical perspective: Pregnancy

Improvements in obstetrical care, medical knowledge, access to better nutrition, increases in standard of living, and access to health care have all contributed to improved survival of mothers and their infants in the 21st century. The increased risk for morbidity and mortality during pregnancy, delivery, and post-partum is recorded throughout history. Worldwide, maternal morbidity rates (MMR) per 100,000 deliveries within 42 days of childbirth were between 800 and 1000 per 100,000 live births in the early 1800s and have now fallen to less than 10 deaths per 100,000 live births in high-income countries. Substantial decreases have been also documented in many developing countries, with MMR in 2015 at about 216 deaths per 100,000 live births worldwide [2,3]. Strides are being made in some middle-income countries such as India (MMR 174 per 100,000 in 2015) [3], but less so in certain low-income countries and in those with armed conflict such as the Democratic Republic of Congo (MMR 693 per 100,000 in 2015) [4].

Pregnant women have been documented to have increased susceptibility to vaccine-preventable diseases compared to non-pregnant women resulting in increased maternal, fetal, and neonatal morbidity and mortality. Historical records on smallpox infections in the 19th century report increased case fatality rates and adverse outcomes among pregnant women [5,6]. The increased susceptibility of pregnant women and their fetuses to viral illness was again demonstrated in the measles outbreaks in the Faroe Islands in 1846 and in Greenland in 1951 [7–13]. During the influenza pandemics of 1918 and 1957, high rates of mortality were reported among pregnant women. One report of influenza among 1350 pregnant women in 1918 in the United States (US) showed mortality rates of 27%, while another study during the same time period of 86 pregnant women with influenza infection in Chicago reported a 45% mortality rate [11,12]. During the 1957 pandemic, influenza was listed as the leading cause of death for pregnancy-associated deaths in Minnesota; half of the women of reproductive age who died due to influenza were pregnant at the time [13]. Adverse pregnancy outcomes including high rates of miscarriage and preterm birth were reported among pregnant women during the influenza pandemic of 1918 [11,12]. In addition, concern for increase in congenital defects of fetuses in pregnant women affected by the Asian influenza pandemic of 1957 and seasonal influenza have been reported [13–18]. Over several influenza seasons in the 1970s–1990s, pregnant women were significantly more likely to be hospitalized and to present for medical visits than non-pregnant women [19,20]. This finding was reaffirmed during the H1N1 influenza pandemic (2009), when pregnant women and their fetuses had an increased risk for morbidity and mortality compared to women who were not pregnant [21–23].

The need from a historical perspective: Early childhood

Infant mortality rates have also been decreasing worldwide over the past century. In urban settings in the US and Europe in the late 1800s, up to 30% of children died before their first birthday compared with current infant rates in developing countries of 30.5 deaths per 1000 live births [24,25]. Global childhood mortality rates in children less than 5 years of age have fallen from 18.4% in 1960 to 4.3% in 2015. In 2016, 75% of all deaths in children under 5 years still occurred in the first year of life, demonstrating the need for continued improvement. The highest rates of childhood mortality today occur in the neonatal period, or first month of life, due in large part to complications of birth, prematurity, infections, and congenital anomalies [26]. Although infant survival has dramatically improved through improved perinatal care, increased emphasis on the prenatal visits for women, medically-attended deliveries, and infant follow-up is ongoing internationally with support from the World Health Organization (WHO) and other partners. Immunization is playing a significant role in this effort to improve early childhood survival.

History of immunization in pregnant women

Reports of vaccination date back as far as the 17th and 18th century with the use of smallpox inoculation (also known as variolation) to prevent smallpox infection in China, Turkey and the African continent prior to its spread to Europe and America [27,28]. Historic records published in the 19th century demonstrated that compared to women who had not received smallpox vaccine prior to pregnancy, women who had been vaccinated had at least partial protection against smallpox during pregnancy [5]. I...