The influenza season of 2014-2015 was notable for a poor antigenic match between the vaccine and the flu strain in the US, as well as a higher proportion of elderly individuals being hospitalized than in previous years[i]. This year, several healthcare organizations have switched over to a high-dose influenza vaccine for patients 65 and over.
The high-dose influenza vaccine has been available since 2009, but until recently there wasn’t clinical evidence to support the theoretical advantage over vaccines with the standard-dose. High-dose trivalent vaccine is a vaccine which contains increased antigen in order to better stimulate an immune response in elderly persons.
In a trial of almost 32,000 patients at least 65 years of age in 126 centers in the United States and Canada, patients were randomized to receive either high-dose trivalent influenza vaccine or traditional dose trivalent vaccine[ii]. The study encompassed two consecutive flu seasons, one in which had low influenza activity, and where there was a moderate-to-good match between the vaccine antigens and the strain and one season in which there was high activity and in which there was a poor match between vaccine antigens and the strain affecting the community.
Laboratory confirmed influenza was studied as the clinical endpoint. Ultimately, 1.9% of patients in the Standard Dose and 1.4% of patients in the High-dose group developed laboratory confirmed influenza. This represented a 24.2% improvement relative in protection in the High-dose Group versus Standard Dose. When narrowed to similar strains (antigenic near match) this improvement in efficacy was about 35.4%. There was no significant difference in adverse effects of the vaccine.
Given the notable improvement in performance of high-dose vaccine in the 65 and older population relative to standard dose, at Golden Living we have decided to make high-dose vaccine available in order to better protect our patients. Standard-dose vaccine will also still be available.
We will continue our close surveillance during flu season for outbreaks, and continue to stress adherence to our infection control practices. Please encourage your patients and Golden Living employees to get vaccinated for influenza. The flu vaccine is not 100% effective, but will significantly decrease risk of contracting the flu, and if an immunized person gets the flu, severity and duration of illness as well as risk of complication is significantly diminished.
If you have any questions about the flu vaccine for this year, please feel free to contact me at email@example.com or Golden Living Director of Pharmacy Steve Hord at firstname.lastname@example.org.
[i] Early Estimates of Seasonal Influenza Vaccine Effectiveness — United States, January 2015 Morbidity and Mortality Weekly Report (MMWR), Jan 16, 2015 / 64(01);10-15
[ii] DiazGranados, CA et al, Efficacy of High-Dose versus Standard-Dose Influenza Vaccine in Older Adults, N Engl J Med Aug 14, 2014;371:635-45.