iGBS3 is a research study of women’s natural immunity against Group B Streptococcus (GBS). We want to find out how much antibody a woman needs to pass to her baby to protect the baby from getting GBS disease. This will help in developing a vaccine.

To do this, we need to take a small sample of cord blood from a large number of women. Because this needs to be done just after delivering the baby, we will be using verbal consent approach. Any woman who does not want to give these samples can refuse at any time and no samples will be taken. Cord blood samples will be stored locally and then sent to St George’s University of London.

If a baby develops GBS disease in the first 3 months of age, the parent will be asked for written consent for us to retrieve the stored cord blood sample as well as an additional sample of blood from the baby in order to measure antibodies in it. These antibodies will be compared with the antibodies from GBS colonised women delivering infants who remained healthy.

Duration of study

90 days of life.


Medical Research Council and Minervax.

The other pathogens sub-study is funded by Pfizer.


St George’s, University of London

Population (age group)

Women ≥ 16 years of age.