No effect of resistance exercise on antibody responses to influenza vaccination in older adults: a randomized control trial

Older adults are at elevated risk for morbidity and mortality caused by influenza. Vaccination is the primary means of prophylaxis, but protection is often compromised in older adults. As acute eccentric resistance exercise mobilizes immune cells into muscle, it may enhance vaccination response. PURPOSE: Compare antibody responses to influenza vaccination in older adults who performed resistance exercise prior to vaccination to those who did not exercise. METHODS: 29 resistance training-naive older adults (20 women, 73.9 +/- 5.3 years) were randomized to 1 of 3 groups: vaccination in the same arm that exercised (Ex-S), vaccination in the opposite arm that exercised (Ex-OP), and seated rest (No-Ex). Exercise was unilateral and consisted of 10 sets of 5 eccentric repetitions at 80% of the pre-determined concentric one repetition maximum. Lateral raises were alternated with bicep curls. No-Ex sat quietly for 25 min. Following exercise or rest, all subjects received the 2018 quadrivalent influenza vaccine (Seqirus Afluria) in the non-dominant deltoid. Antibody titers against the four influenza vaccine strains were determined by hemagglutinin inhibition assays at baseline, 6-, and 24-weeks post-vaccination. Group differences in antibody titers by time were assessed by restricted maximum likelihood mixed models. Fold-changes in antibody titers 6- and 24-weeks from baseline were compared between groups by Kruskal-Wallis tests. RESULTS: No significant group x time effects were found for any strain. Groups did not differ in fold-increase of antibody titers 6- and 24-weeks post-vaccination. Although seroconversion rates remained low, only one subject (Ex-S) reported flu-like symptoms 18 weeks post-vaccination. CONCLUSION: Acute arm eccentric exercise did not influence antibody titers to the influenza vaccine delivered post-exercise in older adults. More strenuous exercise may be required for exercise to act as an adjuvant.