Compressed influenza vaccination: a good idea for older adults?

  • Smith KJ & al.
  • Am J Prev Med
  • 14 Feb 2019

  • curated by Liz Scherer
  • Clinical Essentials
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Takeaway

  • Deferring influenza vaccination until October or later may decrease effects of waning vaccine effectiveness (VE), improve protection in older (>65 years) adults.
  • Benefits may be reversed by early season influenza peaks, substantial vaccine uptake declines.

Why this matters

  • Balance maximizing VE persistence with avoiding missed opportunities to vaccinate older adult patients.

Key results

  • Assuming no declines in uptake during an average influenza season (February peak), compressed vaccination vs status quo resulted in overall influenza case incidence of 5.06% vs 5.09%, respectively (difference, 11,423 cases in 49.2M people), 481 fewer hospitalizations, 134 fewer deaths.
  • Early influenza peaks: compressed vaccination rarely favored in seasons with early peaks, never favored in all 4 strains, VE scenarios if overall uptake declined >1.6%.
  • Average/late illness peaks: always favored if uptake declined by 5.1, or 5.6% points.

Study design

  • Markov modeling study analyzing tradeoffs between intraseason influenza vaccine waning in older adults (>65 years) receiving status quo (August-May) vs compressed vaccination (October-May).
  • Funding: National Institute of General Medical Sciences.

Limitations

  • Degree of waning linked to high-dose vaccines still unknown.
  • Potential heterogeneity unaccounted for.
  • VE waning for new vaccines unavailable.
  • Herd immunity unmeasured.