medwireNews: Influenza vaccination gives rise to an adequate immune response among patients with rheumatic conditions, researchers report.
The study included 137 patients with autoimmune inflammatory rheumatic disease and 54 healthy controls who were vaccinated with a trivalent seasonal influenza vaccine including purified hemagglutinin (HI) of the A/Brisbane/59/2007 (H1N1), A/Brisbane/10/2007 (H3N2), and B/Brisbane/60/2008 (B) strains.
The rheumatic patients included 109 individuals with rheumatoid arthritis, 15 with ankylosing spondylitis, 10 with psoriatic arthritis, and one each with mixed connective tissue disease, juvenile rheumatoid arthritis, and adult-onset Still’s disease.
Katja Lakota (University Medical Centre Ljubljana, Slovenia) and co-investigators found that serum HI antibody titers for all three strains increased significantly from pre-vaccination to 18–90 days post-vaccination in both patients with rheumatic disease and healthy controls.
They report that the likelihood of seroprotection – defined as HI antibody titers of at least 40 units – was not compromised among rheumatic patients compared with healthy controls, with rates ranging from 89% to 100% for the three strains across the groups.
Patients with rheumatic disease did, however, have significantly lower geometric mean titers of H3N2 HI antibodies than healthy controls (312.0 vs 1065.0 units), but titers for the other strains were comparable among the groups.
Subgroup analysis by the type of immunosuppressive drug used demonstrated 100% seroprotection rates in response to the H3N2 and B strains among patients taking a number of agents – including sulfasalazine, adalimumab, etanercept, tocilizumab, and infliximab – but rates of B strain seroprotection were 89% and 96% among patients treated with rituximab and methotrexate, respectively.
The poorest rates of H1N1 seroprotection were also observed among rituximab-treated patients, at 56%, while 86–91% of patients taking methotrexate, adalimumab, etanercept, or tocilizumab were seroprotected, as were a comparable 92% of healthy controls.
The researchers also investigated the immunogenicity of a pandemic influenza vaccine containing the A/California/7/2009 (H1N1pdm) strain in 93 of the patients with rheumatic disease and 15 healthy controls, and 63 rheumatic patients received a second dose of the pandemic vaccine after 3–5 weeks according to guideline recommendations. None of the healthy controls received a second vaccination.
Levels of HI antibodies to the H1N1pdm strain increased to a similar degree in patients with rheumatic diseases and healthy controls after the first vaccination, and a comparable 77% and 80%, respectively, achieved seroprotection. Only an additional 7% of patients met the criteria for seroprotection after the second vaccination.
Therefore, “we can now conclude that influenza vaccination is immunologically active for [rheumatic disease] patients, with little value of the second dose of the pandemic vaccine,” write Lakota and team in Clinical Rheumatology.
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