OBJECTIVES: Baloxavir marboxil is a novel antiviral treatment for influenza reducing the viral load in individuals infected with influenza. Baloxavir marboxil is effective in reducing illness duration and complications from influenza. Historically, antivirals against influenza have not been reimbursed in the Netherlands. However, after the COVID pandemic there is an increased uncertainty regarding the spread and severity of influenza in the population. We assessed the cost-effectiveness and budget impact of using baloxavir marboxil in the Netherlands for patients aged 60 and above and high-risk population who may not be adequately protected by the annual influenza vaccination.

METHODS: We built models to assess the cost-effectiveness and 5-year budget impact of baloxavir marboxil in addition to the vaccination program for influenza in the Netherlands. The cost-effectiveness was assessed from the societal perspective over a lifetime horizon. To account for various potential influenza seasons, we modelled various scenarios based on influenza incidence, type of circulating influenza virus, severity of complications and effectiveness vaccination strategy.

RESULTS: Our preliminary base-case analysis results show an incremental cost-effectiveness ratio of €8,500 per quality-adjusted life year (QALY), with a 57% probability of being cost-effective at a willingness-to-pay threshold of €20,000 per QALY. The average budget impact was €5.7 million, although this can range from €1.9 million to €10.5 million based on the incidence, vaccine effectiveness and vaccination coverage. The mean annual productivity gains were estimated at 8,200 days.

CONCLUSIONS: The use of baloxavir marboxil versus no use of antivirals for the elderly and high-risk population in the Netherlands was found to be cost-effective. The budget impact will vary depending on the epidemiological (outbreak) situation. As the incidence of influenza and vaccine effectiveness are currently difficult to predict, it is worthwhile to invest in antiviral treatment for influenza to alleviate potential health losses, but also reduce influenza-related productivity losses.