Moving maternal Group B Streptococcal vaccines into clinical effectiveness trials.

Lead Research Organisation: St George's, University of London
Department Name: Institute of Infection & Immunity


Infections during the first month of life are a leading cause of death in Africa and Group B Streptococcus (GBS) is emerging as a major pathogen. GBS is a bug (bacterium) that normally lives in the gut and vagina of otherwise healthy women. GBS can cause lethal infections in pregnant women and also leads to stillbirths and premature births. It can be passed from mother to baby at birth or in breastmilk. Once passed on, GBS either remains harmless or causes severe pneumonia, sepsis and meningitis in newborn babies. One way a mother protects her baby is by passing antibody against GBS through the placenta and in breastmilk after birth. However, we do not yet know how much antibody needs to be passed in this way to protect babies from disease. It is also unclear how the GBS bacterium changes from harmless coloniser to potentially fatal bacteria.

At present, babies in Africa are still dying or being born too early and too small because of infections like GBS. Our research group is dedicated to finding out why GBS passes from mother to child, what levels of "protective" antibody need to be passed through the placenta to stop babies from getting sick in the first place and how to prevent GBS disease through new treatments such as maternal vaccination. Before a vaccine can be given to pregnant women, we need to make sure that it is safe and acceptable. We also need to make sure that the amount of "protective antibody" is the same in different countries and look out for potential problems that would make a vaccine less effective.

We will use these answers to change how we look after pregnant women and monitor their babies for signs of infection. We do this so that we can improve the health of women and their babies and prevent GBS infections. Our planned work includes the following:

1. Developing a statistical model to understand how different types of bacteria might change the amount of antibody we make following infection
2. Following babies in Uganda and taking blood samples to work out what types of GBS (and other infections) make babies sick and how much antibody a mother needs to pass to her baby to protect them against infection;
3. Engaging with women in the Uganda to understand whether a vaccine given to pregnant women to prevent GBS - which is currently being developed - is likely to be well received and taken up sufficiently for it to be effective.
4. Using the hospital electronic medical records to develop a system to monitor vaccines given in pregnancy


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