Cost-effectiveness of the adjuvanted quadrivalent influenza vaccine in the elderly Belgian population

Background Between 2015 and 2019, when 62% of Belgian adults aged & GE;65 years were vaccinated with standard quadrivalent influenza vaccines, influenza caused an average of 3,905 hospitalizations and 347 premature deaths per year in older adults. The objective of the present analysis was to estimate the cost-effectiveness of the adjuvanted quadrivalent influenza vaccine (aQIV) compared to the standard (SD-QIV) and high-dose (HD-QIV) vaccines in elderly Belgians. Research Design and Methods The analysis was based on a static cost-effectiveness model that captured the evolution of patients infected with influenza and was customized with available national data. Results Vaccinating adults aged & GE;65 years with aQIV instead of SD-QIV would decrease the number of hospitalizations by 530 and the number of deaths by 66 in the 2023-2024 influenza season. aQIV was cost-effective compared to SD-QIV with an incremental cost of euro15,227/quality-adjusted life year (QALY). aQIV is cost-saving when compared to HD-QIV in the subgroup of institutionalized elderly adults who were granted reimbursement for this vaccine. Conclusion In a health care system striving to improve the prevention of infectious diseases, a cost-effective vaccine such as aQIV is a key asset to reduce the number of influenza-related hospitalizations and premature deaths in older adults. Plain Language Summary Many older Belgians who get the flu are likely to go to hospital or even die. Some flu vaccines have been specially designed for adults 65 years old and older including one that contains a higher amount of flu particles and another that contains a unique additive called an adjuvant. Both vaccines improve the body's response to flu infection, but the adjuvanted vaccine is not yet available in Belgium. We used an economic model to compare hypothetical medical spending on Belgians who were vaccinated with the adjuvanted flu vaccine, the high dose flu vaccine, and a standard flu vaccine. We found that the adjuvanted vaccine would reduce flu hospitalizations and deaths in the elderly, which would in turn reduce medical spending on influenza in Belgium.