The potential economic impact of the updated COVID-19 mRNA fall 2023 vaccines in Japan

This analysis estimates the economic and clinical impact of a Moderna updated COVID-19 mRNA Fall 2023 vaccine for adults at least 18 years in Japan. A previously developed Susceptible Exposed Infected Recovered (SEIR) model with a 1 year analytic time horizon (September 2023 to August 2024) and consequences decision tree were used to estimate symptomatic infections, COVID19 related hospitalizations, deaths, quality adjusted life years (QALYs), costs, and incremental cost-effectiveness ratio (ICER) for a Moderna updated Fall 2023 vaccine versus no additional vaccination, and versus a Pfizer-BioNTech updated mRNA Fall 2023 vaccine. The Moderna vaccine is predicted to prevent 7.2 million symptomatic infections, 272,100 hospitalizations and 25,600 COVID-19 related deaths versus no vaccine. In the base case (healthcare perspective), the ICER was 1,300,000 Yen/QALY gained ($9,400 USD/QALY gained). Sensitivity analyses suggest results are most affected by COVID 19 incidence, initial vaccine effectiveness (VE), and VE waning against infection. Assuming the relative VE between both bivalent vaccines apply to updated Fall 2023 vaccines, the base case suggests the Moderna version will prevent an additional 1,100,000 symptomatic infections, 27,100 hospitalizations, and 2,600 deaths compared to the Pfizer-BioNTech vaccine. The updated Moderna vaccine is expected to be highly cost effective at a 5 million Yen willingness to pay threshold across a wide range of scenarios.