High Dose Flu Shot More Effective in RA Patients 

A high dose influenza vaccine provided rheumatoid arthritis (RA) patients with greater protection than a standard dose vaccine in a randomized, modified double-blind, active-controlled trial. 

RA patients (n = 279; mean age, 61 years; 80% female) were classified into groups based on the treatment they received three months before enrolling in the study and during the study period: disease-modifying antirheumatic drugs (DMARDS) (Group 1 [G1]), anti-cytokine therapy (Group 2 [G2]), and anti-B-cell therapy and small molecules (Group 3 [G3]). Patients received either a high dose vaccine (high dose trivalent inactivated influenza vaccine: HD-TIV, n = 139) or the standard vaccine (standard dose quadrivalent inactivated influenza vaccine: SD-QIV, n = 140). Researchers also measured seroprotection (SP, % with hemagglutination inhibition [HI] titres ≥ 1:40 at day 28) and seroconversion (SC, at least a four-fold HI antibody increase from baseline) rates. At baseline, the groups had similar SP rates. 

The HD-TIV group had significantly higher SC rates than the SD-QIV patients for the A/HongKong/4801/2014 strain (H3N2) (22.3% vs 8.6%), B/Brisbane/60/2008 (B/Bris) strain (44.6% vs 28.6%), and A/California/7/2009 and A/Michigan/45/2015 (H1N1) (51.1% vs 30.0%) strains. SP rates were also higher for all strains in the HD-TIV group (H3N2, 48.5% vs 30.9%; B/Bris, 60.9% vs 50.7%; H1N1, 80.4% vs 73.5%). In adjusted analyses for age; vaccine type; treatment groups G1, G2, and G3; Charlson comorbidity index; and RA duration, the only response predictor besides vaccine dose was age. HD-TIV patients were more than two times as likely to H3N2 seroconvert (odds ratio [OR], 2.84; 95% confidence interval [CI] 1.38-5.87) and H1N1 seroconvert (OR, 2.33; CI 1.42-3.85), and about twice as likely to B/Bris seroconvert (OR, 1.91; CI 1.15-3.17). 

The findings were presented at the 2018 American College of Rheumatology meeting. 

People with RA are at a nearly three-fold increased risk of getting the flu, and previous research has found that vaccination in RA patients is associated with lower risk of hospitalization for certain infections and lower mortality. However, while vaccine is currently the most effective protection, antibody responses and protection are low for RA patients, the researchers noted. 

The study authors concluded, “In seropositive RA patients, the use of HD-TIV substantially improves the immune response to vaccination compared to SD-QIV. This is the first study documenting a successful intervention to enhance vaccine responses in immunocompromised hosts.” 

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Source: American College of Rheumatology 

Kaitlyn D’Onofrio is a digital medical writer. She is interested in musculoskeletal health, the effect of exercise on health, and mental health awareness. When she’s not writing for DocWire, Kaitlyn is teaching yoga classes in her community, promoting wellness to her students.