OBJECTIVES :

Influenza is recognised as an important cause of morbidity and mortality in human populations, resulting in an average of over 21,000 influenza-associated deaths each year in England alone, with 85% of influenza-associated deaths in those over the age of 65. Quadrivalent Influenza Vaccine High-Dose (QIV-HD) has been specifically developed for the over 65 population, containing 4-times more antigen than current standard dose (SD) vaccines. The objective of this study is to estimate the cost-effectiveness of QIV-HD compared to adjuvant Trivalent Influenza Vaccine (aTIV) using clinically relevant endpoints.

METHODS :

A static decision tree model was used to compare influenza cases, GP consultations, hospitalisations, and deaths resulting from influenza complications. Due to a sparsity of trial-based evidence and heterogeneous findings from observational studies for aTIV, three different relative vaccine efficacy scenarios were investigated for QIV-HD versus aTIV. In addition, cost-effectiveness was assessed for QIV-HD versus aTIV for a base case analysis in which hospitalisations were defined as due to influenza/pneumonia. Discounted QALY losses were included for hospitalisations and in-hospital deaths. Analyses were conducted from a UK healthcare system perspective over a one-year time horizon.

RESULTS :

Base case results, with hospitalisation defined as influenza/pneumonia events, indicate that QIV-HD would be considered a cost-neutral vaccination strategy (ICER: £824/QALY), considerably below the £20,000 willingness to pay threshold, delivering superior health outcomes in the over 65 population compared with the current approach using aTIV. When broader definitions of hospitalisations were considered, QIV-HD was shown to be the dominant vaccination strategy compared to aTIV across most scenarios assuming various vaccine efficacy inputs for aTIV for both lab-confirmed influenza cases and hospitalisations.

CONCLUSIONS :

QIV-HD could be a highly cost-effective, and in some cases dominant, alternative to aTIV in England and could reduce the annual public health burden of influenza-related complications.