A new report from the World Health Organization (WHO) and the London School of Hygiene & Tropical Medicine (LSHTM) reveals the global impact of Group B streptococcus (GBS) – a common bacterium that can be transmitted in the womb, during birth, or in the early weeks of life — leading to around 150,000 deaths of babies each year, more than half a million preterm births and significant long-term disability.
Although the bacterium is harmless for most pregnant women who carry it, it can be extremely serious when it passes to babies during pregnancy, childbirth or in the early weeks of life.
The report calls urgently for the development of maternal vaccines against GBS to reduce this toll, emphasizing they could be highly cost-effective — with significant health benefits — in all regions of the world.
Several GBS vaccine candidates are in development, but none of them are available, despite having been in the pipeline for several decades.
An average of 15% of all pregnant women worldwide — nearly 20 million annually — carry the GBS bacterium in their vagina, usually without symptoms. It can then spread from a pregnant woman to her unborn baby in the womb, or to newborns during labor.
Currently, antibiotic prophylaxis administered to a woman during labor is the main means of preventing GBS disease in newborn infants, if the bacterium is detected during pregnancy. However, even in regions with high prophylactic coverage, there remain significant health risks, since this intervention is unlikely to prevent most GBS associated stillbirths, preterm births, or GBS disease that occurs later after birth.
The largest burden of GBS is in low- and middle-income countries, where screening and intrapartum antibiotic administration are most challenging to implement, and a vaccine is therefore most urgently needed, the Who said. The highest rates of maternal GBS are found in sub-Saharan Africa (accounting for around half of the global burden), and Eastern and South-Eastern Asia.