Group B Streptococcus causes 150,000 stillbirth and infant deaths every year

Almost 22 million pregnant women around the world (i.e. roughly one in five) are carriers of Group B Streptococcus (GBS) bacteria, one of the leading causes of morbidity and mortality in infants under three months old, but most cases go undetected and untreated. These are the results of the first global study of GBS burden at the maternal, fetal, newborn and infant level, published as a series of 11 papers in Clinical Infectious Diseases. The study underlines the urgent need for a vaccine that, if administered to pregnant women, could prevent 230,000 cases and 100,000 stillbirths and infant deaths every year.

The first comprehensive study to estimate the global burden of GBS infections has been coordinated by the London School of Hygiene and Tropical Medicine (LSHTM) and funded by the Bill &Melinda Gates Foundation. More than 100 researchers from all over the world, including ISGlobal researchers, collected available data worldwide and estimated the number of GBS cases and its impact on maternal and child health for 195 countries in 2015. Africa has the highest GBS disease burden (54% of cases and 65% of stillbirth and infant deaths), although the infection is present in all regions of the world. The top five countries in number of pregnant women colonised with the bacterium are: India, China, Nigeria, USA and Indonesia.

“This is the most updated and detailed information published to date on GBS burden at the global level – an introductory paper, 9 meta-analysis of available data at different levels, and a final paper with estimates based on such analysis” underlines ISGlobal researcher Lola Madrid, who led one of the papers (Infant Group B Streptococcal disease incidence and serotypes worldwide: systematic review and meta-analyses) and is co-author in three others Other ISGlobal researchers that contributed data for the study are Quique Bassat, Clara Menéndez and Jaume Ordi.

“Diagnosis and intrapartum antibiotic treatment of GBS colonised women is not easy to do in low-resource countries, where many births occur at home. In addition, giving antibiotics to 21.7 million women would amplify the antimicrobial resistance problem” explains Joy Lawn, from LSHTM. “A maternal vaccine could save many more lives by not only avoiding newborn deaths but also protecting the fetus and the mother”, adds Anna Seale, from the same institute.

The authors argue that the vaccine is technically feasible (several are currently in development) and that the estimates provided by the study will help determine the vaccine-preventable mortality, the size and cost of a licensure trial, and the cost-efectiveness of a GBS vaccine. They conclude that maternal GBS vaccination “has the potential to reduce this disease burden worldwide, within the next generation and including the poorest families”.

Copyright LSHTM 2017

Reference:

The Burden of Group B Streptococcus Worldwide for Pregnant Women, Stillbirths and Children. Clinical Infectious Diseases. 15 Nov 2017. Vol 65, Suppl 2.