Abstract
Streptococcus agalactiae, or Lancefield group B streptococcus (GBS), is the most frequent cause of serious bacterial sepsis, including neonatal meningitis, in UK neonates. Early-onset neonatal GBS infection, but not late-onset, can be prevented by screening to identify high-risk pregnancies and administering penicillin during delivery. A vaccine has been developed as an alternative means of prevention but it is awaiting a randomized trial before being available for general use. In this review we examine the published literature to assess the morbidity and mortality attributable to neonatal GBS infection, quantify the screening performance of the two alternative modes of screening (microbiological and risk factor based), review the evidence on the efficacy of the vaccine, and estimate the numbers of deaths and cases of serious disability that each strategy in turn might prevent in the UK, in order to assess the most effective means of prevention for the UK.