Beefed-Up Flu Vaccine for Seniors

The current issue of The Medical Letter (1486; January 18, 2016) includes an article on Fluad, an adjuvanted seasonal flu vaccine for older adults that will become available in the US later this year for use in the 2016-2017 influenza season. Fluad has been available in Europe since 1997 for persons >65 years old, so it is unlikely to give us any unpleasant surprises with regard to its safety. But as with any new influenza vaccine, its efficacy is more difficult to pin down.

Fluad is not the first flu vaccine to become available for senior citizens. Fluzone High-Dose was approved in 2009 after it was shown to induce significantly greater antibody responses than standard-dose vaccines and to be more effective in preventing influenza. A double-blind trial randomized almost 32,000 participants >65 years old to receive standard-dose or high-dose vaccine, followed them for 6-8 months, and recorded serious adverse events (eg, death, hospitalization, serious pneumonia) considered possibly related to influenza. Those who received the high-dose vaccine had significantly fewer serious adverse events, especially fewer episodes of serious pneumonia (4.44 vs. 7.38 per 1000 participant-seasons) (CA DiazGranados et al.Vaccine 2015; 33:4988).

The best evidence for the superior efficacy of the adjuvanted flu vaccine compared to unadjuvanted flu vaccine was an observational study in Northern Italy, where the adjuvanted vaccine was already in wide use among older patients. The risk of hospitalization for influenza or pneumonia was 25% lower among those who received the adjuvanted vaccine, even though physicians generally recommended it only for patients who were older and had more functional impairment and comorbidities (S Mannino et al. Am J Epidemiology 2012; 176:527).

Which is better, Fluzone High-Dose or Fluad? It would take a comparative trial to find out, and I am not sure either manufacturer would risk that. What is clear, though, is that senior citizens, with their less robust antibody production and greater susceptibility to complications, could benefit from receiving one or the other.

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  1. indicates that Duke University is currently doing the comparative trial of Fluzone High-Dose versus Fluad during the 2017-2018 flu season. Hopefully, that will provide direction on the better product for the 2018-2019 flu season. “FLUAD vs. Fluzone High-Dose Study.” May 2017. Sponsor Duke University. Identifier: NCT03183908

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