Group B Strep (GBS) is the most common cause of life-threatening infection in newborn babies in the UK.
Most developed countries offer all pregnant women a GBS test late in pregnancy and then offer antibiotics in labour when the test result is positive, and have seen significant drops in the rates of GBS infection in newborn babies. In the UK, since 2003 we have used a risk-based approach to identify which newborn babies are most likely to develop GBS infection. If a risk factor arises, the mother is offered antibiotics in labour to reduce the risk of the newborn baby developing the infection. Our rate has risen.
However effective they are, antibiotics given in labour can only prevent most early-onset GBS infections – those occurring in babies in their first week of life. To prevent more GBS infections, we need a vaccine which could prevent not only early-onset GBS infection but also the less common stillbirths, maternal infections and late-onset infections, which are more likely to present as meningitis, caused by GBS.
Vaccines against GBS are already in development and being tested. If one or more shown vaccines are shown to be both safe and effective, they could be offered to pregnant women to protect their babies from this devastating infection. However, we do not yet know what level of antibody is needed to protect babies against GBS infection in their first three months of life – without that, scientists can’t easily license a GBS vaccine for pregnant women.
The iGBS3 trial is collecting comprehensive information about the amount of antibody that protects babies from GBS infection, so that the researchers can establish what the components of a GBS vaccine need to be to reduce GBS infection in babies.
We at GBSS have been closely involved right from the start of this trial, and look forward to its results informing future GBS vaccine development.
What information is being collected by iGBS3?
iGBS3 has two phases:
- Phase 1: small amounts of cord blood will be collected from all eligible women and blood from babies who have GBS infection at time of of their infection – this is to establish the link between the level of antibody to GBS infection and the antibody levels in cord blood
- Phase 2: once Phase 1 is completed, either
- (a) if antibody correlation is strong, blood collection will continue from babies who have GBS infection only.
- (b) if antibody correlation is weak, to continue cord blood collection only and blood collection from babies who have GBS infection.
It is estimated that the study will include up to 170,000 women from up to 40 maternity units throughout England, Wales and Scotland.
Is my hospital taking part in iGBS3?
Maternity Units that are taking part in the GBS3 trial will be invited to take part in iGBS3 for the main study. Read more about the GBS3 Trial here. Any units in the UK can take part in the surveillance sub-study recruitment of babies who have GBS infection).
For more information
There’s more information on the iGBS3 Trial website here.