Key result
Higher pre-existing titers against historical influenza strains increased the likelihood of achieving Day 21 seroprotective titers for A(H1N1) (OR 1.41; 95% CI 1.09-1.82).
Why the study?
Does pre-existing immunity to historical influenza strains improve antibody response to the inactivated trivalent influenza vaccine in adults aged 50-80 years?
Population
264 individuals aged 50-80 years
Design
Cohort
Follow-up
21 days
Authors
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May support tailored influenza vaccination strategies in older adults; hypothesis-generating and should not yet change practice.
Cohort (n=264)
Yes
Does pre-existing immunity to historical influenza strains improve antibody response to the inactivated trivalent influenza vaccine in adults aged 50-80 years?
Odds Ratio: 1.41 (95% CI 1.09–1.82)
p-value: p=<0.01
Pre-existing immunity to historical influenza strains is associated with improved antibody responses to current influenza vaccines in older adults.
Ross et al. (2014) conducted a cohort in Influenza (n=264). Pre-existing hemagglutination inhibition titers against historical influenza strains vs. Fewer or no seroprotective responses against historical strains was evaluated on Day 21 titers ≥ 1:40 for the vaccine A(H1N1) strain among those with Day 0 titer <1:40 (OR 1.41, 95% CI 1.09-1.82, p=<0.01). Higher pre-existing titers against historical influenza strains increased the likelihood of achieving Day 21 seroprotective titers for A(H1N1) (OR 1.41; 95% CI 1.09-1.82).
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