Age-Targeted Vaccination for Reducing Clostridioides Difficile Infection in England: A Coupled Mathematical-Economic Modeling Analysis

OBJECTIVES: Recent results from a phase 2 extension and phase 3 trial of the leading vaccine candidate against Clostridiodes difficile infection (CDI) demonstrated high efficacy in reducing medically attended cases and an immune response that persisted for 48 months. This research aims to use mathematical and economic modelling to bridge the gap between the potential vaccine’s clinical efficacy and its operational deployment in England.

METHODS: Key risk factors for CDI were incorporated into a hospital-level mathematical model used to simulate the impact of the vaccine on reducing disease burden in England. Model outputs of interest included medically attended cases, intensive care admissions and deaths associated with CDI, as well as costs and QALYs. Hospital costs and costs of years of life lost due to premature mortality averted per vaccine course were computed for a 10-year time horizon.

RESULTS: Simulations showed that vaccinating only those over the age of 74 years old could be expected to halve CDI cases and ICU admissions while reducing deaths by almost two-thirds. 20% of lives saved would be achieved through indirect benefits i.e., due to reduced transmission. Issuing around 5 million vaccine courses in both the first and second year to protect the eldest, and 0.4 million annual courses thereafter to maintain effective coverage of all those over 64 years old, can be expected to avert £378 in costs (2023£) and gain 0.046 QALYs per vaccine course by the fourth year of roll out.

CONCLUSIONS: Should a safe, highly efficacious C. difficile vaccine be licensed, it could be positioned very well for providing considerable economical health benefits to England’s population. Future work should expand the current analysis to other countries.