Clinical Edge

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Efficacy of High-Dose Influenza Vaccine in Seniors

Vaccine; ePub 2018 Oct 1; Robison, et al

High-dose (HD) influenza vaccine provided superior protection for seniors against influenza hospitalization during the 2016-17 influenza season in the Portland metropolitan area, a new study found. The differential vaccine effectiveness (VE) was assessed by a nested series of models across matching strata. For an exact match for high-dose and standard-dose seniors, matching elements included exact age, gender, residence type, race/ethnicity, provider bias, and residence area. Among the findings:

  • A simple aggregate comparison of influenza hospitalization risk showed no added HD effectiveness.
  • For nested models, adding strata increased VE in this study population.
  • Among 23,712 matched pairs of HD to standard-dose vaccinated seniors, the HD vaccine was 30.7% more effective in preventing influenza-related hospitalization.

Citation:

Robison SG, Thomas AR. Assessing the effectiveness of high-dose influenza vaccine in preventing hospitalization among seniors, and observations on the limitations of effectiveness study design. [Published online ahead of print October 1, 2018]. Vaccine. doi:10.1016/j.vaccine.2018.09.050.

Commentary:

This is a very important study. In this examination of a large US city and type of influenza vaccination and hospitalization, researchers found that the high dose vaccine was 30% more effective in seniors for preventing hospitalizations. Only about 70% of our senior citizens get vaccinated against influenza each year. For our patients that do elect to get vaccinated, we should try to get them the vaccine that is more effective for outcomes like hospitalizations. This real-world trial tried to eliminate biases like certain “healthy” patients get immunized more or that clinicians are more likely to encourage vaccination in their “sicker” patients. The ACIP does not give the high-dose influenza vaccine a preferential recommendation but at this point, should they? —John Russell, MD