Core Findings - The first season results of a randomized study indicate that adjuvanted and high-dose influenza vaccines have comparable effectiveness against PCR-confirmed influenza, with a relative vaccine effectiveness (rVE) of 1.5% [2][3][4] Study Overview - The study is a collaborative effort between CSL Seqirus and a large health system, involving approximately 480,000 individuals aged 65 and older over two seasons [4][6] - The first season enrolled 429,600 individuals, with 212,877 receiving adjuvanted inactivated influenza vaccine (aIIV) and 216,723 receiving high-dose inactivated influenza vaccine (HD-IIV) [6] - The study aims to test the hypothesis that aIIV is non-inferior to HD-IIV, with a non-inferiority margin of -20% [5] Effectiveness and Recommendations - No significant difference was found in the effectiveness of aIIV and HD-IIV for preventing hospitalization or emergency department visits for PCR-confirmed influenza, as well as for all-cause community-acquired pneumonia [2][3] - The findings support the CDC's Advisory Committee on Immunization Practices (ACIP) recommendation for preferential use of adjuvanted or higher-dose influenza vaccines for adults aged 65 and older [3] Future Directions - The second season of the study is ongoing, with pooled analyses planned after the 2024-2025 season [4][6] - The study's design allows for routine clinical practice vaccination, enhancing the real-world applicability of the findings [5]
New Data Presented at IDWeek 2024 Show Adjuvanted and High-Dose Influenza Vaccines are Comparable in Protecting Adults 65 Years of Age and Older Against Seasonal Influenza