Group B Streptococcus clinical trials

Developing a Controlled Human Infection Model for Group B Streptococcus (CHIM_GBS)

Group B Streptococcus (GBS) is the leading cause of neonatal sepsis and meningitis. In 2015, it was estimated that worldwide there were at least 320,000 infants with invasive GBS disease, 90,000 infant deaths and 10,000 cases of children with disability related to GBS meningitis. Maternal rectovaginal colonization with GBS is the biggest risk factor for neonatal GBS sepsis and meningitis within the first 6 days of life, with transmission of the bacteria from mother to baby occurring around the time of birth. An estimated 20-35% of pregnant women are colonised with GBS. 1-2% of neonates born to GBS-colonised women develop invasive GBS disease in the absence of intrapartum antibiotic prophylaxis (IAP). The current strategy to prevent neonatal GBS is to give antibiotics during labour, called IAP. This has various limitations and is not easily achieved outside of high income settings. Additionally, widespread antibiotic use raises concerns about antibiotic resistance. A better approach would be a vaccine for GBS however in order to test any vaccines it would be necessary to develop a controlled human infection model whereby healthy female volunteers are artificially colonised with GBS to test the vaccines efficacy. Before developing these human infection models researchers need to better understand how women become colonised with GBS and whether antibodies in the blood and at the mucosal surfaces provide protection. This study will be observational and will test the antibody levels at the vaginal mucosa and in the blood of a group of women who are naturally colonised with GBS at the start of the study and a group who are not colonised. Investigators will follow women up over 12 weeks to observe how colonisation changes and the effect that this has on the mucosal and blood stream antibody concentrations. This will inform the development of human infection studies.