Presentation (CTI)

OBJECTIVES: This systematic literature review investigated published health economic modelling approaches used for assessing the potential cost-effectiveness of a maternal GBS vaccination programme.
METHODS: Embase and MEDLINE® were searched from 2006 to 16th April 2026, using a pre-defined search strategy, followed by two-stage screening and data extraction. Key information extracted included modelling approach, comparator details, vaccine effectiveness assumptions, utilities, costs, outcomes and cost-effectiveness drivers.
RESULTS: 836 studies were screened, of which 10 were included. Studies used either a decision-tree (n=6) or hybrid decision-analytical approach (decision-tree with embedded Markov nodes, n=4) to assess cost-effectiveness. Comparators varied by geography (no intervention, risk-based intrapartum antibiotic prophylaxis [IAP], or screening plus IAP), limiting cross-study comparability. Vaccine efficacy ranged from 50-90% due to lack of Phase III data, with effectiveness typically modelled as a function of both efficacy and serotype coverage; some studies also adjusted efficacy downward in preterm infants due to reduced transplacental antibody transfer (n=5). While all models captured early- and late-onset disease, mortality, and long-term sequelae, broader outcomes such as stillbirth and preterm birth were often excluded or assessed only in scenario analyses due to limited evidence. Models relied on proxy data for utilities and costs, and limited inclusion of broader societal impacts and maternal impacts. Parametric uncertainty was consistently explored in scenario/ sensitivity analyses across all studies; vaccine price, efficacy, and disease incidence were identified as key drivers of cost-effectiveness. Across all studies, maternal GBS vaccination was deemed likely cost-effective under base case and scenario assumptions.
CONCLUSIONS: Modelling approaches assessing the cost‑effectiveness of maternal GBS vaccination are consistent but strongly assumption‑driven. Despite the use of assumptions due to data paucity, findings were generally consistent across scenario analyses and suggest maternal GBS vaccination is likely cost-effective under the assumptions evaluated.