Objectives: To assess the clinical and economic impact, and cost-effectiveness, of a 2024 Winter and Summer COVID-19 Vaccination Campaign (2024 Vaccination Campaign) in Australia compared to no 2024 Vaccination Campaign. Design: Modelling study using a COVID-19 susceptible-exposed-infect-recovered (SEIR) dynamic transmission model and a COVID-19 vaccination and infections consequences decision analytic model. Setting, Participants: Australia; Winter 2024 COVID-19 vaccination targeting adults aged ≥18 years, with those aged ≥ 65 years eligible for an additional Summer 2024 dose. Intervention: 2024 Vaccination Campaign using a Moderna variant-updated mRNA vaccine compared to no 2024 Vaccination Campaign. Main outcome measures: Projected number of symptomatic infections, hospitalisation, deaths, and cases of long COVID prevented; quality-adjusted life-years (QALYs) gained, incremental cost of the 2024 Vaccination Campaign, and incremental cost-effectiveness ratio (ICER) of the campaign compared to No Vaccination Campaign. Results: Compared to no Vaccination Campaign, a 2024 Vaccination Campaign in Australia is predicted to prevent 241,600 symptomatic infections, 13,500 COVID-19 hospitalisations, 1,200 deaths, and 11,900 cases of long COVID, representing a decrease of 16%, 23%, 26%, and 17%, respectively. This resulted in 19,200 fewer QALYs lost. COVID-19 treatment costs saved with the 2024 Vaccination Campaign was $511.7 million. This partially offset the costs associated with vaccination and adverse event treatment ($1.03 billion), resulting in an incremental 2024 Vaccination Campaign cost of $522 million for a population of 26.3 million, with 4.35 million vaccinations administered. The ICER was $27,100/QALY gained. Increasing the vaccine coverage rate to that observed with influenza vaccination prevented more cases of infection, hospitalisation, and deaths compared to the base case, with an ICER of $34,400/QALY gained. Conclusion: Even in the endemic setting with high hybrid immunity, substantial clinical and economic benefits to vaccinating those aged ≥18 years against COVID-19 remain. These benefits may be amplified with increased vaccination coverage.

MK is a shareholder in Quadrant Health Economics, Inc., which was contracted by Moderna, Inc. to conduct this study. AL and MM are consultants at Quadrant Health Economics Inc. KJ, EB, PM and EK are employees of Moderna, Inc. and may own stock/stock options in the company.

This study was funded by Moderna, Inc., Cambridge, MA, USA

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