Cost-Utility of Quadrivalent Versus Trivalent Influenza Vaccine in Germany, Using an Individual-Based Dynamic Transmission Model

Seasonal influenza infection is primarily caused by circulation of two influenza A strain subtypes and strains from two B lineages that vary each year. Trivalent influenza vaccine (TIV) contains only one of the two B-lineage strains, resulting in mismatches between vaccine strains and the predominant circulating B lineage. Quadrivalent influenza vaccine (QIV) includes both B-lineage strains. The objective was to estimate the cost-utility of introducing QIV to replace TIV in Germany. An individual-based dynamic transmission model (4Flu) using German data was used to provide realistic estimates of the impact of TIV and QIV on age-specific influenza infections. Cases were linked to health and economic outcomes to calculate the cost-utility of QIV versus TIV, from both a societal and payer perspective. Costs and effects were discounted at 3.0 and 1.5 % respectively, with 2014 as the base year. Univariate and probabilistic sensitivity analyses were conducted. Using QIV instead of TIV resulted in additional quality-adjusted life-years (QALYs) and cost savings from the societal perspective (i.e. it represents the dominant strategy) and an incremental cost-utility ratio (ICUR) of a,not sign14,461 per QALY from a healthcare payer perspective. In all univariate analyses, QIV remained cost-effective (ICUR <a,not sign50,000). In probabilistic sensitivity analyses, QIV was cost-effective in > 98 and > 99 % of the simulations from the societal and payer perspective, respectively. This analysis suggests that QIV in Germany would provide additional health gains while being cost-saving to society or costing a,not sign14,461 per QALY gained from the healthcare payer perspective, compared with TIV

The Potential Cost-Effectiveness of Quadrivalent versus Trivalent Influenza Vaccine in Elderly People and Clinical Risk Groups in the UK: A Lifetime Multi-Cohort Model

<div><p>Objective</p><p>To estimate the potential cost-effectiveness of quadrivalent influenza vaccine compared with trivalent influenza vaccine in the UK.</p><p>Methods</p><p>A lifetime, multi-cohort, static Markov model was constructed, with nine age groups each divided into healthy and at-risk categories. Influenza A and B were accounted for separately. The model was run in one-year cycles for a lifetime (maximum age: 100 years). The analysis was from the perspective of the UK National Health Service. Costs and benefits were discounted at 3.5%. 2010 UK vaccination policy (vaccination of people at risk and those aged ≥65 years) was applied. Herd effect was not included. Inputs were derived from national databases and published sources where possible. The quadrivalent influenza vaccine price was not available when the study was conducted. It was estimated at £6.72,15% above the trivalent vaccine price of £5.85. Sensitivity analyses used an incremental price of up to 50%.</p><p>Results</p><p>Compared with trivalent influenza vaccine, the quadrivalent influenza vaccine would be expected to reduce the numbers of influenza cases by 1,393,720, medical visits by 439,852 complications by 167,357, hospitalisations for complications by 26,424 and influenza deaths by 16,471. The estimated base case incremental cost-effectiveness ratio (ICER) was £5,299/quality-adjusted life-year (QALY). Sensitivity analyses indicated that the ICER was sensitive to changes in circulation of influenza virus subtypes and vaccine mismatch; all other parameters had little effect. In 96% of simulations the ICER was <£20,000/QALY. Since this analysis was completed, quadrivalent influenza vaccine has become available in the UK at a list price of £9.94. Using this price in the model, the estimated ICER for quadrivalent compared with trivalent vaccination was £27,378/QALY, still within the NICE cost-effectiveness threshold (£20,000-£30,000).</p><p>Conclusions</p><p>Quadrivalent influenza vaccine could reduce influenza disease burden and would be cost-effective compared with trivalent influenza vaccine in elderly people and clinical risk groups in the UK.</p></div

Probabilistic sensitivity analysis.

<p>A: cost-effectiveness plane; B: cost-effectiveness acceptability curve. ICER, incremental cost-effectiveness ratio; QALY, quality-adjusted life-year.</p

Input data for vaccine efficacy and coverage.

a<p>No difference in input values between healthy and at-risk populations.</p>b<p>Adjusted for the proportion of the 0–4 age group falling within the product license (i.e. 38.62%).</p

Base case results.

<p>PEP, post-exposure prophylaxis; QALY, quality-adjusted life-year.</p>a<p>All deaths due to complications, as it was assumed that mortality from uncomplicated influenza was 0.</p

Input data for costs.

a<p>4.9% of hospitalised patients are treated in intensive care <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098437#pone.0098437-Turner1" target="_blank">[24]</a>, and this cost was included in the cost of hospitalization.</p><p>A&E, accident and emergency; CNS, central nervous system; GI, gastrointestinal; GP, general practitioner; LOS, length of stay; OM, otitis media; PEP, post-exposure prophylaxis; URTI, upper respiratory tract infection.</p

Results in the first year.

a<p>All deaths due to complications, as it was assumed that mortality from uncomplicated influenza was 0.</p

Input data for age-dependent probabilities.

a<p>No difference in input values between healthy and at-risk populations.</p>b<p>Identical for influenza A and B.</p>c<p>97.0% present to a GP and 3.0% to A & E, in all age groups <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0098437#pone.0098437-Tappenden1" target="_blank">[23]</a>.</p>d<p>No difference between cases presenting to GP or A & E, or not seeking medical advice.</p>e<p>Risk of death assumed to be the same for all complications.</p><p>A&E, accident and emergency; GP, general practitioner.</p

Multi-cohort approach.

<p>Multi-cohort approach.</p