Group B Streptococcal Disease Worldwide for Pregnant Women, Stillbirths, and Children: Why, What, and How to Undertake Estimates?

Abstract

Improving maternal, newborn, and child health is central to Sustainable Development Goal targets for 2030, requiring acceleration especially to prevent 5.6 million deaths around the time of birth. Infections contribute to this burden, but etiological data are limited. Group B Streptococcus (GBS) is an important perinatal pathogen, although previously focus has been primarily on liveborn children, especially early-onset disease. In this first of an 11-article supplement, we discuss the following: (1) Why estimate the worldwide burden of GBS disease? (2) What outcomes of GBS in pregnancy should be included? (3) What data and epidemiological parameters are required? (4) What methods and models can be used to transparently estimate this burden of GBS? (5) What are the challenges with available data? and (6) How can estimates address data gaps to better inform GBS interventions including maternal immunization? We review all available GBS data worldwide, including maternal GBS colonization, risk of neonatal disease (with/without intrapartum antibiotic prophylaxis), maternal GBS disease, neonatal/infant GBS disease, and subsequent impairment, plus GBS-associated stillbirth, preterm birth, and neonatal encephalopathy. We summarize our methods for searches, meta-analyses, and modeling including a compartmental model. Our approach is consistent with the World Health Organization (WHO) Guidelines for Accurate and Transparent Health Estimates Reporting (GATHER), published in The Lancet and the Public Library of Science (PLoS). We aim to address priority epidemiological gaps highlighted by WHO to inform potential maternal vaccination.

Keywords: global burden; group B Streptococcus; maternal; neonatal; stillbirth.

Figure 1.

Causes of deaths for neonates and children aged <5 years in 2015. Source: Liu et al [64].

Figure 2.

Map of United Nations subregions that will be used for reporting input data and results. Borders of countries/territories in map do not imply any political statement.

Figure 3.

Disease schema for outcomes of perinatal group B Streptococcus. Abbreviations: GBS, group B Streptococcus; NE, neonatal encephalopathy.

Figure 4.

Overview of the articles in this supplement to estimate the worldwide burden of group B Streptococcus. Abbreviations: EOGBS, early-onset group B Streptococcus; GBS, group B Streptococcus; LOGBS, late-onset group B Streptococcus; NE, neonatal encephalopathy; NDI, neurodevelopmental impairment.

Figure 5.

Data cascade for GBS disease showing the gap for care and measurement and the biases at added at each step. Adapted from Fitchett et al [59] and applied to the framework of the human immunodeficiency virus identification and treatment cascade. Abbreviation: GBS, group B Streptococcus.