Estimates of the Burden of Group B Streptococcal Disease Worldwide for Pregnant Women, Stillbirths, and Children

Background We aimed to estimate, for the first time, the global burden of Group B Streptococcus (GBS), with regards to invasive disease in infants, as well as in pregnant and postpartum women, and fetal infection/stillbirth. Intrapartum antibiotic prophylaxis (IAP) is currently used for prevention of early onset infant disease in high-income contexts, but is difficult to implement globally, and may contribute to antimicrobial resistance. Maternal GBS vaccines are in development. Methods For 2015 live births, we used data from systematic reviews and meta-analyses (presented in separate papers in this GBS supplement) and a compartmental model to estimate: exposure to maternal GBS colonisation, cases of infant invasive GBS disease, deaths, and disabilities. We applied incidence or prevalence data to estimate cases of maternal and fetal infection/stillbirth, and infants with invasive GBS disease presenting with neonatal encephalopathy (NE). We applied risk ratios to estimate numbers of preterm births attributable to GBS. Uncertainty was also estimated. Worldwide in 2015, we estimated 2 05 000 (uncertainty range [UR], 101000–327000) infants with early-onset disease and 1 14 000 (UR, 44000–326000) with late-onset disease, of whom a minimum of 7000 (UR, 0–19000) presented with neonatal encephalopathy. There were 90 000 (UR, 36000–169000) deaths in infants<3 months age, and, at least 10 000 (UR, 3000–27000) children with disability each year. There were 33 000 (UR, 13000–52000) cases of invasive GBS disease in pregnant or postpartum women, and 57 000 (UR, 12000–104000) fetal infections/stillbirths. Up to 3.5 million preterm births may be attributable to GBS. Africa accounted for 54% of estimated cases and 65% of all fetal/infant deaths. A maternal vaccine with 80% efficacy and 90% coverage could prevent 1 07 000 (UR, 20000–198000) stillbirths and infant deaths. Conclusions Our conservative estimates suggest that GBS is a leading contributor to adverse maternal and newborn outcomes, with at least 4 09 000 (UR, 144000–573000) maternal/fetal/infant cases and 1 47 000 (UR, 47000–273000) stillbirths and infant deaths annually. An effective GBS vaccine could reduce disease in the mother, the fetus, and the infant. Acknowledgement Additional authors include H Blencowe (1), S Cousens (1), CJ Baker, L Bartlett, C Cutland, MGGravett, PT Heath, M Ip, K Le Doare, SA Madhi, CE Rubens, SK Saha, SJ Schrag, A Sobanjo-ter Meulen, J Vekemans