October 16, 2015
2 min read

High-dose flu vaccine reduces hospitalizations in elderly

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SAN DIEGO — Results from a large, randomized controlled trial suggested high-dose influenza vaccination reduced hospitalizations among nursing home residents.

“As people get older, their response to vaccines goes down,” Stefan Gravenstein, MD, MPH, from the department of health services, policy and practice at Brown University School of Medicine, said during a presentation at IDWeek 2015. “When it comes to the flu vaccine, there’s some question about how effective it is in older populations. The high-dose vaccine was developed in response to this.”

Gravenstein noted that in a previous randomized controlled trial, the high-dose (HD) vaccine was 24.2% more effective than the standard-dose (SD) vaccine in preventing laboratory-confirmed clinical influenza, and similar results have been found in a retrospective cohort analysis using Medicare data.

Gravenstein and colleagues evaluated the clinical effectiveness of the HD and SD Fluzone influenza vaccines (Sanofi Pasteur) at reducing hospitalizations, mortality and overall functioning in more than 53,000 long-term residents during the 2013-2014 influenza season, when the predominant virus was influenza A(H1N1). The researchers also assessed vaccine uptake among nursing home staff when the SD vaccine was offered for free. The study included 823 Medicare-certified nursing homes located within 50 miles of a city belonging to the CDC’s influenza surveillance system. Each facility was randomly assigned to one of four groups:

  • HD vaccine for residents and free SD vaccine for staff;
  • HD vaccine for residents and usual care for staff;
  • SD vaccine for residents and free SD vaccine for staff; and
  • SD vaccine for residents and usual care for staff.

Gravenstein said the groups had similar characteristics. Results suggested hospitalizations were significantly reduced in nursing homes offering the HD vaccine compared with the SD vaccine (19.7% vs. 20.9%; adjusted OR = 0.93; 95% CI, 0.88-0.99). To prevent one hospitalization, 81 (95% CI, 53-182) residents are needed to receive the HD rather than SD vaccine. Gravenstein said the type of vaccine dose had no effect on mortality and overall functioning, and access to a free vaccine did not significantly improve uptake among nursing home staff.

“Studies have shown that the high-dose vaccine works well in an outpatient population,” he said. “This suggests it also works well in a long-stay population.” – by John Schoen


DiazGranados C. N Engl J Med. 2014;doi:10.1056/NEJMoa1315727.

Gravenstein S, et al. Abstract LB-8. Presented at: IDWeek; Oct. 7-11, 2015; San Diego.

Izurieta HS, et al. Lancet Infect Dis. 2015; doi:10.1016/S1473-3099(14)71087-4.

Disclosure: Gravenstein reports being a consultant for Merck, Novartis, Novavax, Pfizer and Sanofi Pasteur, which funded the study. Please see the full study for a list of all other authors’ relevant financial disclosures.