Health Economic Modeling Approaches for Assessing the Value of a Clostridioides Difficile Vaccination Program: A Literature Review
Author(s)
Alexander J. Bourne, MSc1, Cale Harrison, MSc2, Jack Said, MSc2.
1Access and Value (Contractor), Pfizer Ltd, Tadworth, United Kingdom, 2Access and Value, Pfizer Ltd, Tadworth, United Kingdom.
1Access and Value (Contractor), Pfizer Ltd, Tadworth, United Kingdom, 2Access and Value, Pfizer Ltd, Tadworth, United Kingdom.
OBJECTIVES: Clostridioides difficile (C.diff) outbreaks pose a substantial threat to public health globally, prompting the investigation of a C.diff vaccine in recent years. This targeted literature review explored the mathematical modelling approaches used for assessing the potential socioeconomic value of implementing a C.diff vaccine programme to help inform future modelling activities.
METHODS: MEDLINE® and Embase were searched from their inception date up to 10th July 2024, using a pre-defined search strategy, followed by two-stage screening and data extraction. Key information extracted from studies included modelling approach, modelled time horizon, transmission pathways, natural history, and vaccine assumptions.
RESULTS: 1,577 studies were screened, of which seven studies were ultimately included within the review. Three different modelling approaches were identified, agent-based (n=3), decision tree (n=2), and dynamic transmission modelling (n=2). C.diff natural history was represented in each of the modelling approaches, with all studies including health states for at least susceptible, infected and recovered individuals. A key difference in modelled natural history was the depiction of C.diff colonisation. Colonised patients (patients with the presence of constant bacterium over time) were stratified based on whether they were asymptomatic or symptomatic in six of the identified studies. C.diff transmission was represented in five of the seven studies, characterised through three key contact pathways; healthcare workers, patients and the environment. Vaccine assumptions varied across the models, a vaccine was either assumed to alleviate C.diff symptoms without affecting colonisation (n=4) or alleviate symptoms and eradicate colonisation (n=3).
CONCLUSIONS: In the current literature, there exists a high degree of heterogeneity in modelling approaches for C.diff transmission as well as diverse key modelling assumptions around potential vaccination impact, reservoirs of transmission and health states. This highlights the complexity of C.diff vaccinology and the careful considerations needed to produce fit for purpose future models.
METHODS: MEDLINE® and Embase were searched from their inception date up to 10th July 2024, using a pre-defined search strategy, followed by two-stage screening and data extraction. Key information extracted from studies included modelling approach, modelled time horizon, transmission pathways, natural history, and vaccine assumptions.
RESULTS: 1,577 studies were screened, of which seven studies were ultimately included within the review. Three different modelling approaches were identified, agent-based (n=3), decision tree (n=2), and dynamic transmission modelling (n=2). C.diff natural history was represented in each of the modelling approaches, with all studies including health states for at least susceptible, infected and recovered individuals. A key difference in modelled natural history was the depiction of C.diff colonisation. Colonised patients (patients with the presence of constant bacterium over time) were stratified based on whether they were asymptomatic or symptomatic in six of the identified studies. C.diff transmission was represented in five of the seven studies, characterised through three key contact pathways; healthcare workers, patients and the environment. Vaccine assumptions varied across the models, a vaccine was either assumed to alleviate C.diff symptoms without affecting colonisation (n=4) or alleviate symptoms and eradicate colonisation (n=3).
CONCLUSIONS: In the current literature, there exists a high degree of heterogeneity in modelling approaches for C.diff transmission as well as diverse key modelling assumptions around potential vaccination impact, reservoirs of transmission and health states. This highlights the complexity of C.diff vaccinology and the careful considerations needed to produce fit for purpose future models.
Conference/Value in Health Info
2025-11, ISPOR Europe 2025, Glasgow, Scotland
Value in Health, Volume 28, Issue S2
Code
EE494
Topic
Economic Evaluation, Epidemiology & Public Health, Methodological & Statistical Research
Disease
Infectious Disease (non-vaccine), Vaccines