Clinical Edge

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Influenza Vaccine Efficacy in High-Risk Patients

Vaccine; ePub 2018 Nov 9; Shang, Chung, et al

Among patients with high-risk conditions, influenza vaccination provided protection against medically-attended influenza at levels approaching patients without high-risk conditions. This according to a recent study that examined influenza vaccine effectiveness (VE) among patients with high-risk medical conditions in the US from 2012-2016. Researchers analyzed influenza VE among outpatients by high-risk condition, age, and flu type during the study period. They found:

  • Overall, 9,643 (38%) of 25,369 patients enrolled during 4 influenza seasons had high-risk conditions; 2,213 (23%) tested positive for influenza infection.
  • For all ages, VE against any influenza was lower among patients with high-risk conditions than those without (41% vs 48%).
  • However, VE among patients with high-risk conditions did approach similar levels to patients without these conditions.
  • VE among children and adults with high-risk conditions was not different from among those without.
  • VEs against flu A(H3N2), (H1N1)pdm09, and B were similar in patients with and without high-risk conditions.


Shang M, Chung JR, Jackson ML, et al. Influenza vaccine effectiveness among patients with high-risk medical conditions in the United States, 2012-2016. [Published online ahead of print November 9, 2018]. Vaccine. doi:10.1016/j.vaccine.2018.10.093.


This is a reassuring study that informs us that patients who need the flu vaccine the most will have a response on par with lower risk patients. We should continue to recommend the influenza vaccine for all our patients, low risk and high risk included, that are over 6 months of age. This study was done with standard vaccines. It will be interesting to see how this study turns out when looking at high dose vaccine among patients over 65 years of age in recombinant vaccines in suggested populations. —John Russell, MD