Using economic models and cost-utility analyses to explore the cost-effectiveness of vaccines

PRMA Consulting is now Avalere Health

 

 

Using economic models to explore the cost-effectiveness of different vaccine candidates

The type of economic model that is used in vaccine cost-effectiveness appraisals normally depends on the characteristics of the infectious disease and the vaccine candidate. The benefits and disadvantages of the different model types need to be considered before an appropriate approach is selected.

Both the German Standing Committee on Vaccination (STIKO) and the World Health Organization (WHO) provide specific guidance on the type of models that should be used to explore the cost-effectiveness of different vaccine candidates. Both decision-makers recommend that dynamic transmission models should be employed when evidence exists that vaccinations could lead to indirect effects such as herd immunity. For example, dynamic transmission models are normally used to evaluate flu vaccines. POLYMOD contact matrices could be utilized in these models to estimate contact patterns in different target groups.

WHO guidance suggests that if probabilities of infection, transmission, or recovery differ substantially between many relatively small population groups, then individual-based modeling should be considered.

On the other hand, static models should be utilized for vaccine products that do not have an indirect effect on transmission and are unlikely to change susceptibility to infection in people who have not been immunized.

 

 

Cost-utility analyses are the preferred type of analysis for vaccines across most markets

Cost-utility analyses are the preferred type of analysis across most markets, with incremental benefits being presented as cost per quality-adjusted life-year (QALY). Cost-effectiveness analyses, which present outcomes using natural units relevant to the vaccine in question such as hospitalizations, deaths, or life-years, could also be used in cases where the impact of the vaccination on health-related quality of life is not considered an important consequence.

The time frame and analytic horizon of the economic model should be contingent on the disease type and characteristics of the vaccination. Thus, a narrower time horizon should be used when modeling the effects of vaccine that offer short duration of protection or limited herd immunity.

On the other hand, an infinite time horizon has been used for an intervention with permanent effect such as the global eradication of measles. In Germany, the time frame of the analysis should be sufficiently long to capture the three phases of the analysis: the run-in phase where the epidemiological situations in the pre-vaccination period are reproduced; the evaluation phase where both positive and negative effects of the vaccination can be depicted and taken into account; and finally, the steady-state phase, where an epidemiological plateau is reached. For example, a multigenerational time horizon has been used for flu vaccinations.

 

Different markets have different preferences regarding the perspective of the economic evaluation of vaccines

Different markets have different preferences regarding the perspective of the economic evaluation. WHO guidelines suggest that the perspective of the economic analysis should reflect national guidelines if the audience is the national decision-maker.

Where specific guidelines are absent, the economic evaluations should adopt the societal perspective and include all related effects and costs regardless of who benefits from or pays for them.

• US: the economic analysis should reflect the healthcare sector perspective (including medical costs borne by third-party payers or paid for out-of-pocket by patients), societal perspective, or ideally both.
• Germany: the Statutory Health Insurance needs to be reflected in the base-case while the societal perspective could be explored as part of the sensitivity analyses.
• UK: the perspective of the National Health Service needs to be reflected in the base-case of the economic analysis.
• France: the base-case of the analysis is expected to reflect the perspective of the French national healthcare system and the patients; this is known as the French collective perspective.

 

Vaccine economic analyses are based on a comparison between the proposed product and current standard of care

Similar to pharmaceuticals, vaccine economic analyses are based on a comparison between the proposed product and the current standard of care. WHO guidelines recommend that if current clinical practice is not sufficiently cost-effective compared with other available options, the analysis should include all other relevant options, such as a best available alternative, a viable low-cost alternative, or a do-nothing option.

Non-vaccine interventions against the same disease should be considered where appropriate and should be captured by the current or alternative practice comparators. Thus, in cases where first-in-class vaccines are being evaluated, the comparator should be outcomes without vaccination where current epidemiology of the disease and associated costs are being considered.

When a next-in-class vaccine is being appraised, existing vaccines from the same class should be used as a benchmark for clinical and economic benefits. In all markets, the economic analyses are expected to reflect comparisons of the proposed vaccine product against all options that are locally available and that might be replaced by the new vaccine.