Session Type: Abstract Submissions (ACR)
Background/Purpose: In 2010 the Advisory Committee on Immunization Practices from the CDC recommended that all children should receive the trivalent seasonal influenza vaccine containing the A/California/7/2009(H1N1)-like virus with a specific protocol of two doses in subjects under 9 years old. There is, however, no data regarding this vaccine immunogenicity and safety in young children with autoimmune rheumatic diseases (ARD).
Methods: 42 ARD patients and 12 healthy controls were initially recruited. One juvenile idiopathic arthritis patient had typical uncomplicated febrile seizure after first dose and did not receive the second dose and 3 patients and one control did not complete the study. Therefore, 38 ARD patients [25 juvenile idiopathic arthritis, 5 juvenile dermatomyositis, 3 juvenile systemic lupus erythematosus, 3 juvenile scleroderma and 2 primary vasculitis] and 11 healthy children completed the study and received two doses of a non-adjuvanted preparation of influenza A/California/7/2009 (H1N1) virus-like vaccine. They were clinically evaluated before and 21 days after the second dose of vaccination and serology for anti-H1N1 antibody was performed by hemagglutination inhibition (HI) assay. Seroprotection and seroconversion rates, geometric mean titres (GMT) and factor increase (FI) in GMT (ratio of the GMT after vaccination to the GMT before vaccination) were calculated. Adverse events were also evaluated.
Results: Current age (7 vs. 7.8 years, p=0.55) and female gender (76.3 vs. 63.6%, p=0.45) were comparable in ARD patients and controls. Five (13.2%) patients were not receiving any drug, 18 (47.4%) patients were under non-steroidal anti-inflammatory drugs and 11 (28.9%) under prednisone, with a median current dose of 15mg (4-40). Twenty-three (60.5%) were taking methotrexate, 6 (15.8%) cyclosporine, one (2.6%) azathioprine and 7 (18.4%) anti-TNF agents. Pre-vaccination seroprotection rates (p=1.0) and GMT (p=0.63) were comparable between patients and controls. Three weeks after immunization seroprotection (81.6 vs. 81.8%; p=1.0), seroconversion rates (81.6 vs. 90.9%; p=0.66), GMT (151.5 vs. 282.1, p=0.26) and the FI in GMT (16.7 vs. 36.3; p=0.226) were similar in patients and controls, with both groups achieving adequate response according to the European Medicines Agency and Food and Drug Administration standards. The analysis of the possible factors influencing seroconversion showed no difference in demographic data, leukocytes and lymphocytes count or frequency of immunosuppressive drugs use (including prednisone, methotrexate, cyclosporine, azathioprine and anti-TNF agents) between seroconverted and non-seroconverted patients (p>0.05). No severe adverse events were observed.
Conclusion: Two doses of the non-adjuvanted influenza A H1N1/2009 vaccination induced an effective antibody response in young children with ARD independent of demographic characteristics, lymphocytes count and immunosuppressive treatment. Adverse events were rarely observed suggesting vaccine recommendation for this group of patients. (ClinicalTrials.gov, #NCT01151644)
N. E. Aikawa,
L. M. Campos,
R. M. R. Pereira,
J. C. B. Moraes,
A. C. Ribeiro,
M. D. C. S. Timenetsky,
C. A. Silva,
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ACR Meeting Abstracts - https://acrabstracts.org/abstract/immunogenicity-and-safety-of-two-doses-of-influenza-a-h1n1%e2%81%842009-vaccine-in-young-autoimmune-rheumatic-diseases-patients-under-9-years-old/