Key issues and challenges in estimating the impact and cost-effectiveness of quadrivalent influenza vaccination

Abstract

Evidence has shown that quadrivalent influenza vaccines containing all four subtypes are safe and immunogenic. However, to date there have been few published studies exploring the population-level clinical and economic impact of quadrivalent compared to trivalent influenza vaccines. Economic evaluation studies need to be conducted in order to inform country-level decision making about whether (and how to) introduce and replace the current trivalent influenza vaccines with quadrivalent influenza vaccination programs. Several key issues associated with estimating the clinical and economic impact of the trivalent versus quadrivalent vaccines are discussed in this article, particularly the complexities involved in estimating the incremental preventable disease and economic burden. Other factors, such as the indirect (herd) protection from quadrivalent influenza vaccination and the timing of the replacement of trivalent influenza vaccination programs are also discussed.

Keywords::

• cost-effectiveness
• disease impact
• economic evaluation
• influenza
• quadrivalent
• vaccination

Financial & competing interests disclosure

A Newall holds a National Health and Medical Research Council (NHMRC) Training Fellowship (630724 – Australian Based Public Health Fellowship). A Newall is also a member of the Centre for Research Excellence (CRE) funded by the NHMRC (APP1031963). The authors have no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Quadrivalent influenza vaccines contain all four subtypes of influenza known to be circulating globally and have been found to be safe and immunogenic.

• These vaccines have the potential to increase population-level protection against influenza disease and reduce the associated clinical and economic impact of influenza.

• Although there is growing evidence, currently there are few published evaluations of the economic impact of the quadrivalent versus existing trivalent influenza vaccines.

• Estimating the economic benefit of quadrivalent influenza vaccines should include careful estimation of the disease burden attributable to different influenza subtypes.

• Modeling the impact of quadrivalent vaccines may be complicated by cross-protection and the existence of trivalent vaccination programs in many countries.

• The implications of indirect (herd) protection to unvaccinated individuals should be considered when evaluating the impact of alternative programs.

• Decision makers also need to carefully consider how any potential transition from trivalent to quadrivalent would take place to ensure adequate supply.