Group B streptococcus (GBS) is a common cause of severe infection in newborns. It can be passed from mother to baby during labour, and from mothers and others after birth. Most babies colonised with GBS remain well, but some develop GBS infection, usually in the first two days after birth. To reduce the risk of newborn infection, antibiotics can be given to the mother during labour. However, the long-term effects of antibiotics are unknown, and giving antibiotics may contribute to antibiotic resistance.
To determine whether routine testing for GBS in late pregnancy or during labour is effective and cost-effective, the National Institute for Health Research is funding a large study (GBS3) led by the University of Nottingham. The study will provide evidence to the UK National Screening Committee on whether all women should be offered GBS testing in pregnancy or around birth.
To ensure GBS3's findings reflect both the immediate and long-term consequences for babies who develop GBS infection, the study will use mathematical modelling to estimate outcomes through childhood years. To do this, the study will link and assess routinely collected English data from three datasets: the Clinical Practice Research Datalink (CPRD), Hospital Episode Statistics (HES), and the Office for National Statistics.
The aim of the study is to measure and compare survival, health-related quality of life, and healthcare needs of individuals who had and did not have GBS infection as a baby. This will help researchers better understand the long-term outlook for babies who develop GBS infection.
Group B streptococcus (GBS) is a bacterium that colonises the vagina and lower gut of approximately 1 in 4 pregnant women. Although most babies colonised with GBS remain well, approximately one baby in every 1750 will develop GBS infection within 7 days of birth. In the UK, about 40 babies die each year, and 1 in 14 survivors have long-term disability. Intrapartum Antibiotic Prophylaxis (IAP) reduces the risk of mother to baby transmission during labour, but concerns remain about their long-term effects and antimicrobial resistance.
To fill the evidence gap around maternal GBS testing, the National Institute for Health Research (NIHR) has funded a large cluster-randomised controlled trial (GBS3) involving approximately 320,000 participants. The trial will assess whether routine testing of women for GBS colonisation in late pregnancy reduces early-onset neonatal sepsis compared with the current risk-based approach.
An economic evaluation is being conducted alongside GBS3 to extrapolate cost-effectiveness over a lifetime horizon. Recently published data from Denmark and the Netherlands suggest an increased risk of 5-year mortality and neurodevelopmental impairments for children who had infant GBS disease compared to children without the disease. However, their estimates of resource use associated with the disease do not reflect UK practice due to differences in healthcare practices.
In this study, we aim to generate evidence using English data to model progression of infant GBS disease and its impact on health, wellbeing and healthcare use of survivors over time. We will construct a cohort of individuals who had infant disease and a comparison group without infant disease, using CPRD, HES, and ONS data. We will use the cohorts to estimate excess mortality and neurodevelopmental impairments over childhood and adolescent years and healthcare costs for survivors. The study findings can inform other studies, such as those modelling cost-effectiveness of vaccines currently in development.
(1) All-cause mortality at 1, 5, 10, and 15 years of life will be assessed based on ONS mortality data. We will consider assessing mortality over 20 years if the data allows it.
(2) Neurodevelopmental impairments (NDIs) at 1, 5, 10, 15 and 20 years of age (if the data allows) across motor, hearing, vision, cognitive, and social or behavioural domains.
(3) Healthcare resource use and costs at 1, 5, 10, 15 and 20 years of age (if the data allows). Primary care data will include the number and type of consultations with each health care professional, prescriptions, tests and investigations. Secondary care utilisation includes referral, type of admission, length of stay, diagnosis, and procedures undertaken.
Felix Achana - Chief Investigator - University of Oxford
Felix Achana - Corresponding Applicant - University of Oxford
Cynthia Wright Drakesmith - Collaborator - University of Oxford
Jane Daniels - Collaborator - University of Nottingham
Jane Plumb - Collaborator - Not from an Organisation
Jason Madan - Collaborator - University of Warwick
Kate Walker - Collaborator - University of Nottingham
Linda Fiaschi - Collaborator - University of Nottingham
Margaret Smith - Collaborator - University of Oxford
May Ee Png - Collaborator - University of Oxford
Proma Paul - Collaborator - London School of Hygiene & Tropical Medicine ( LSHTM )
Shalini Ojha - Collaborator - University of Nottingham
Stavros Petrou - Collaborator - University of Oxford
HES Accident and Emergency;HES Admitted Patient Care;HES Outpatient;ONS Death Registration Data;Patient Level Index of Multiple Deprivation;CPRD Aurum Ethnicity Record;CPRD Aurum Mother-Baby Link;CPRD Aurum Pregnancy Register