Cost‐Effectiveness and Public Health Effect of Influenza Vaccine Strategies for U.S. Elderly Adults

Abstract

Objectives Four influenza vaccines are available in the US for persons aged ≥65 years: trivalent inactivated influenza vaccine (IIV3), quadrivalent inactivated influenza vaccine (IIV4), a more expensive high-dose IIV3, and a newly approved adjuvanted IIV3, but their cost-effectiveness when all 4 vaccines are compared is unknown. Methods Markov model to estimate the cost-effectiveness and public health benefits of influenza vaccination strategies in US elders. Results IIV3 cost $3690 per quality adjusted life year (QALY) gained compared to no vaccination. Compared to IIV3, IIV4 cost $20,939/QALY gained and, compared to IIV4, high-dose IIV3 cost $31,214/QALY. The model projected 83,775 fewer influenza cases and 980 fewer deaths with high-dose IIV3 compared to the next most effective vaccine, IIV4. In a probabilistic sensitivity analysis, high-dose IIV3 is the favored strategy if willingness to pay is ≥$25,000/QALY gained. Adjuvanted IIV3 cost-effectiveness depends on its price and effectiveness (both not yet determined in the US), but could be favored if its relative effectiveness is 15% greater than IIV3. Conclusions From economic and public health standpoints, high-dose IIV3 for adults ≥65 years old is likely to be favored over the other vaccines, based on currently available data. The cost-effectiveness of adjuvanted IIV3 should be reviewed after its effectiveness compared to other vaccines is determined and its US price established.

Cost-effectiveness and public health impact of alternative influenza vaccination strategies in high-risk adults

“…The present model differs from the original IDA model [9] in the population age cohort and the vaccination strategies recommended for high-risk and non-high-risk 50–64-year-old patients. The model was supplemented with logic to allow the comparison of strategies with unknown vaccine effectiveness, as the comparator strategies are either too new to have generated reliable population data or have not been routinely used in the high-risk middle-aged population.…”

“…The decision analytic Markov model used in this analysis extended the Influenza Decision Analysis (IDA) model, which was developed to evaluate alternative influenza vaccination strategies in the U.S. population, to a high-risk, 50–64 year-old U.S. population [9]. The dynamics of the decision tree, including detailed descriptions of cost and benefit valuations and model assumptions, have been previously reported [9].…”

“…The dynamics of the decision tree, including detailed descriptions of cost and benefit valuations and model assumptions, have been previously reported [9]. The enhanced model used in the present analysis retains the same event logic, where the probabilities of vaccination, illness, complications, treatment, recovery, and death are computed for a hypothetical cohort of individuals for each of 10 monthly cycles corresponding with a single influenza season.…”

“…Cost-effectiveness analyses offer a relatively inexpensive and responsive method of evaluating new vaccination strategies. For example, a cost-effectiveness analysis has demonstrated that high-dose trivalent influenza vaccine is economically reasonable for use in individuals ≥65 years of age, given its increased effectiveness [9]. …”

Reply to: Estimating the Full Value of High‐Dose Influenza Vaccine

“…Ertmer and Chit in a response to our policy recommendations for influenza vaccination strategies in the elderly. 2,3 They state that, it is “difficult to use models to appropriately predict the full public health impact of HD-IIV3.” We agree. However, when population-level data are sparse, models are an excellent option to test the potential impact of alternative policy strategies.…”