Authors: Martha Powell, Future Science Group
In the first study to comprehensively assess the burden of group B streptococcus (GBS), it has been estimated that these infections cause 150,000 stillbirth and infant deaths every year, highlighting the urgent need for better prevention.
Previous data on GBS has focused on infant cases and high-income countries, overlooking the burden in some areas of the world. This study, published recently in Clinical Infectious Diseases and presented at the American Society of Tropical Medicine and Hygiene (ASTMH) Annual Meeting (5–9 November, Baltimore, MD, USA), has provided the first comprehensive report on the burden of GBS, including 2015 data and estimates from every country worldwide.
The findings highlight that GBS is present among pregnant women in all regions of the globe, with an average of 18% of women colonized with the bacteria – although this ranged from 11% of women in Eastern Asia to 37% in the Caribbean. The team went on to conservatively estimate that of the 410,000 GBS cases that occur every year, there are approximately 147,000 stillbirths and infant deaths.
Although several GBS vaccines are under development, none are currently available. This research highlights the necessity of a preventative vaccination, suggesting that a vaccine, which was 80% effective and reached 90% of women, could prevent up to 231,000 infant and maternal GBS cases.
Current GBS prevention varies owing to differences in policies across the world that involve strategies such as antibiotic-use in pregnancy, testing for presence of GBS or identification of colonized women based on clinical risk factors.
Author Joy Lawn (London School of Hygiene & Tropical Medicine, UK) commented: “Too many parents around the world face the death of a baby or a young child – avoidable GBS deaths are happening in every country. Antibiotics currently prevent an estimated 29,000 cases of early-onset Group B Streptococcal disease per year, almost all in high-income settings.
“However, this approach may be difficult in low-income settings where many births take place at home, and laboratory capacity for screening for GBS is limited. In addition, giving antibiotics to 21.7 million women may contribute to antimicrobial resistance – a major global health crisis.”
Co-author, Johan Vekemans (Initiative for Vaccine Research, WHO, Geneva, Switzerland) concluded: “These disease burden estimates highlight the importance of perinatal infection prevention. Existing recommendations should be implemented, but these are insufficient, and the number of affected families remains unacceptable.
“It is now essential to accelerate the GBS vaccine development activities. The technical feasibility is estimated to be high. Guidance highlighting research priorities is available. Work is ongoing to strengthen existing maternal immunization programmes. Next steps include a comprehensive evaluation of cost-effectiveness. We will be working with Professor Lawn and others at London School of Hygiene & Tropical Medicine, and global partners to lead on these activities.”
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Sources: The Burden of Group B Streptococcus Worldwide for Pregnant Women, Stillbirths, and Children, Clin. Infect. Dis. 65, Supplementary 2, doi:10.1093/cid/cix657 (2017); www.lshtm.ac.uk/newsevents/news/2017/group-b-streptococcus-infection-causes-estimated-150000-preventable