Since the 1970s, group B Streptococcus (GBS) has been recognised as the most common cause of bacterial infection in newborn babies, usually presenting within the first 24-48 hours after birth, resulting in disease around the time of birth and up to 3 months of age, although they can occur after this time though this is rare.

Group B Streptococcus is a normal bacterium.  Up to a third of all men and women carry GBS in their intestines without symptoms and roughly a quarter of women of childbearing age carry GBS in the vagina at any one time. GBS is a normal body commensal (an organism that lives on another without harming it). A positive swab result for GBS means a woman is colonised with GBS at the time the swab was taken - not that she or her baby will become ill.

GBS colonisation is normal and does not require treatment with antibiotics (GBS is not a sexually transmitted disease and treatment of a woman carrying GBS and of her partner does not prevent re-colonisation).  The time when antibiotics are effective against GBS infection in newborn babies is when they are given intravenously (through a vein) to a pregnant woman when she goes into labour or her waters break.

(If GBS is found in the urine, this should be treated at the time of diagnosis with oral antibiotics and the treatment repeated if necessary until urine tests come back clear. This is also an indication that the pregnant woman should be offered intravenous antibiotics once labour starts or her waters break.)

Medical research shows that using a risk factor approach to preventing GBS infection in newborn babies would prevent up to 6 out of every potential 10 cases.  And an approach including sensitive testing of low-risk women late in pregnancy as well as offering antibiotics in labour to women at higher-risk would prevent over 8 out of every potential 10 cases - this saves lives!