Group B Streptococcus

Group B strep (GBS) is a common bacterium in men and women and usually lies in the rectum or vagina.  We know that approximately 20-40% of women in the UK are GBS carriers.  GBS is usually harmless and most people are unaware that they have it.  It usually only causes problems if it affects pregnant women, young babies, elderly people or those who are seriously ill.    

GBS is not routinely tested for in pregnant women but may be found during urine tests of vaginal swab tests.  If a mother is found to have GBS, most of the time the infant will be born safely and will not develop infection.  However, there is a small risk that it could spread to the baby during labour and cause a serious infection in the infant e.g., sepsis, pneumonia or meningitis.  At present, if GBS is found in a pregnant woman, or she has given birth to an infant who was previously affected by GBS infection, the woman will be offered antibiotics in labour to reduce the risk of infection to the baby.  There is an extremely small risk that a woman could miscarry or lose their baby as a result of GBS.    

In 2021, there were 441 cases of GBS infections in infants <90 days old in England.  It is estimated that GBS claims around 150,000 babies’ lives a year worldwide with GBS being the leading identified infectious cause of stillbirth and neonatal death in the UK.  Here at St George’s Vaccine Institute, we are conducting a number of trials examining different methods to test for GBS, measuring antibodies against GBS and trialling a number of vaccines against GBS in pregnancy.