Adjuvanted QIV influenza vaccine: some efficacy against severe disease in older adults

  • Beran J & al.
  • Lancet Infect Dis
  • 9 Feb 2021

  • curated by Liz Scherer
  • Clinical Essentials
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Takeaway

  • 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.

Key results

  • 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.
  • Efficacy:
    • 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.

Study design

  • 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.

Limitations 

  • Mismatched H3N2 viruses.
  • Underpowered.
  • Limited generalizability.