Clinical and Economic impact of updated Fall 2023 COVID-19 vaccines in the Immunocompromised Population in Canada

Background: Immunocompromised (IC) individuals are at increased risk of COVID-19 infection-related severe outcomes. Moderna and Pfizer-BioNTech COVID-19 mRNA vaccines are available in Canada, and differences in vaccine effectiveness (VE) have been found between the two in IC individuals. The objective of this analysis was to compare the clinical and economic impact of a Moderna XBB.1.5 updated COVID-19 mRNA Fall 2023 vaccine to a Pfizer-BioNTech XBB.1.5 updated COVID-19 mRNA Fall 2023 vaccine in Canadian IC individuals aged ≥18 years. Methods: A static decision-analytic model estimated the number of COVID-19 infections, hospitalizations, deaths, and resulting quality-adjusted life years (QALYs) over a one-year time horizon (September 2023-August 2024) in the Canadian IC adult population (n=894,580). Costs associated with COVID-19 infection were estimated from health care and societal perspectives. The predicted VE of the updated Moderna vaccine was based on prior variant versions, which were well-matched to the circulating variant. Pfizer-BioNTech VE was calculated based on a meta-analysis of comparative effectiveness between both vaccines (relative risk for Moderna vaccine: infection=0.85 [95%CI 0.75-0.97], hospitalization=0.88 [95%CI 0.79-0.97]). The model combined VE estimates with COVID-19 incidence and probability of COVID-19 related severe outcomes. Sensitivity analyses tested the impact of uncertainty surrounding incidence, hospitalization and mortality rates, costs, and QALYs. Results: Given the expected higher VE against infection and hospitalizations with the Moderna Fall 2023 vaccine, its use is predicted to prevent an additional 2,411 infections (3.6%), 275 hospitalizations (3.7%), and 47 deaths (4.0%) compared to the Pfizer-BioNTech Fall 2023 vaccine, resulting in 330 QALYs gained, and savings of $7.4M in infection treatment costs, and $0.9M in productivity loss costs. Results were most sensitive to variations in VE parameters, specifically the relative risk of infection and hospitalizations between the vaccines, and waning rates. Conclusions: If the Moderna and Pfizer-BioNTech Fall 2023 vaccines protect against infection and hospitalizations similar to previous vaccines, using the Moderna Fall 2023 vaccine would result in substantial public health benefits in IC individuals, as well as provide health care and societal cost savings. ### Competing Interest Statement EB, KaJ, KeJ, and NV are employees of Moderna, Inc and may hold shares and stock options in Moderna, Inc. MK is a shareholder in Quadrant Health Economics, Inc., which was contracted by Moderna, Inc. to conduct this study. KF, AL, and MM are consultants at Quadrant Health Economics Inc. ### Funding Statement This study was funded by Moderna, Inc., Cambridge, MA, USA. ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.