- An adjuvanted quadrivalent influenza vaccine (aQIV) offers some efficacy against severe disease in older adults, even with a seasonal mismatch.
- The aQIV triggered a robust immune response in this randomized trial.
Why this matters
- Editorial: protection against severe disease is more relevant than efficacy against PCR-related endpoints.
- Routine influenza vaccination with a quadrivalent formulation is important for older adults.
- 6761 participants.
- 3379 received aQIV and 3382 a noninfluenza comparator vaccine.
- Mean age, 71.9 years:
- Efficacy analysis: n=6740, per-protocol: n=6603.
- Protocol-defined influenza-like illness:
- 23.0% aQIV vs 23.3% comparator.
- 122 with aQIV vs 118 in comparator group had >1 PCR-confirmed influenza:
- A H3N2: 78.7% aQIV vs 78.1% comparator.
- A H3N2 strain mismatch with vaccine was associated with 89% of culture-confirmed cases.
- 19.8% (multiplicity-adjusted 95% CI, −5.3% to 38.9%) against all influenza.
- 49.9% (−24.0% to 79.8%) against antigenically matched strains (protocol-defined influenza-like illness).
- Adverse event (AE) prevalence:
- 34.3% aQIV vs 32.2% comparator.
- 0.3% (both groups) reported severe injection site pain.
- Unsolicited AEs were mostly mild/moderate in both groups.
- Randomized, stratified, observer-blind, controlled, multicenter phase 3 study assessing aQIV for influenza prevention in adults age ≥65 years vs adults receiving a noninfluenza vaccine.
- Funding: Seqirus UK.
- Mismatched H3N2 viruses.
- Limited generalizability.