How is influenza prevented in elderly persons?

Updated: Apr 23, 2019
  • Author: Hien H Nguyen, MD, MS; Chief Editor: Michael Stuart Bronze, MD  more...
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Vaccination may provide less protection against influenza in patients older than 65 years. In an effort to improve the immunogenicity of influenza virus vaccine in elderly adults, a high-dose trivalent inactivated influenza vaccine (Fluzone High-Dose) was developed. In a multicenter, randomized, double-blind controlled trial involving elderly adults (≥65 years), those who received the high-dose vaccine exhibited a statistically significantly higher seroconversion rate than those who received the standard-dose vaccine. [69]

The high-dose vaccine met superiority criteria for both strains of influenza A, and noninferiority criteria were met for influenza B strains. [69] Seroprotection rates were higher for the high-dose vaccine than for the standard-dose vaccine. The authors suggest that the high-dose vaccine may provide improved immunity for elderly adults.

High-dose influenza vaccine appears to have the potential to prevent nearly one-quarter of all breakthrough influenza illnesses in elderly persons (≥65 years) compared with the standard-dose vaccine, according to results from a phase IIIb-IV double-blind, active-controlled trial. [70, 71] A total of 31,989 participants were randomly assigned to receive either a high dose (IIV3-HD) (60 μg of hemagglutinin per strain) or a standard dose (IIV3-SD) (15 μg of hemagglutinin per strain) of a trivalent, inactivated influenza vaccine. The multicenter trial was performed during the influenza seasons of 2011-2012 and 2012-2013 in Canada and the United States. [70, 71]

These studies also measured the percentage of elderly persons with postvaccination hemagglutination-inhibition titers of 1:40 (the cut-off for seroprotection) or higher was significantly higher in the IIV3-HD group relative to the IIV3-SD group. [70, 71] Laboratory-confirmed influenza (via nasopharyngeal swabs for culture, polymerase chain reaction, or both) occurred in 228 participants in the IIV3-HD group (1.4%) and 301 participants in the IIV3-SD group (1.9%), a relative efficacy of 24.2% (95% confidence interval [CI], 9.7 to 36.5). [70, 71] Although reports of at least one serious adverse event were greater in the IIV3-HD group (8.3%) than in the IIV3-SD group (9.0%) (relative risk, 0.92; 95% CI, 0.85 to 0.99), all resolved by the end of the study and none required discontinuation from the study. [71]

Woods et al found that in sedentary elderly adults, cardiovascular exercise extends influenza vaccine seroprotection. A randomized controlled trial in 144 sedentary but healthy elderly adults showed that peak (3- and 6-week) postvaccine anti-influenza hemagglutination inhibition titers were similar in those who underwent cardiovascular exercise or flexibility and balance training, but those in the cardiovascular exercise group were significantly more likely to have seroprotective titers at 24 weeks, a period that could cover the entire influenza season. [72]


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