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Abstract Introduction Seasonal influenza A (H3N2) virus is an important cause of morbidity and mortality in the last 50 years in population that is greater than the impact of H1N1. Data assessing immunogenicity and safety of this virus component in juvenile systemic lupus erythematosus (JSLE) is lacking in the literature. Objective To evaluate short-term immunogenicity and safety of influenza A/Singapore (H3N2) vaccine in JSLE. Methods 24 consecutive JSLE patients and 29 healthy controls (HC) were vaccinated with influenza A/Singapore/ INFIMH-16-0019/2016(H3N2)-like virus. Influenza A (H3N2) seroprotection (SP), seroconversion (SC), geometric mean titers (GMT), factor increase in GMT (FI-GMT) titers were assessed before and 4 weeks post-vaccination. Disease activity, therapies and adverse events (AE) were also evaluated. Results JSLE patients and controls were comparable in current age [14.5 (10.1-18.3) vs. 14 (9-18.4) years, p = 0.448] and female sex [21 (87.5%) vs. 19 (65.5%), p = 0.108]. Before vaccination, JSLE and HC had comparable SP rates [22 (91.7%) vs. 25 (86.2%), p = 0.678] and GMT titers [102.3 (95% CI 75.0-139.4) vs. 109.6 (95% CI 68.2-176.2), p = 0.231]. At D30, JSLE and HC had similar immune response, since no differences were observed in SP [24 (100%) vs. 28 (96.6%), p = 1.000)], SC [4 (16.7%) vs. 9 (31.0%), p = 0.338), GMT [162.3 (132.9-198.3) vs. 208.1 (150.5-287.8), p = 0.143] and factor increase in GMT [1.6 (1.2-2.1) vs. 1.9 (1.4-2.5), p = 0.574]. SLEDAI-2K scores [2 (0-17) vs. 2 (0-17), p = 0.765] and therapies remained stable throughout the study. Further analysis of possible factors influencing vaccine immune response among JSLE patients demonstrated similar GMT between patients with SLEDAI < 4 compared to SLEDAI ≥ 4 ( p = 0.713), as well as between patients with and without current use of prednisone ( p = 0.420), azathioprine ( p = 1.0), mycophenolate mofetil ( p = 0.185), and methotrexate ( p = 0.095). No serious AE were reported in both groups and most of them were asymptomatic (58.3% vs. 44.8%, p = 0.958). Local and systemic AE were alike in both groups ( p > 0.05). Conclusion This is the first study that identified adequate immune protection against H3N2-influenza strain with additional vaccine-induced increment of immune response and an adequate safety profile in JSLE. ( www.clinicaltrials.gov , NCT03540823).
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INTRODUCTION: Influenza A (H3N2) virus is the most important cause of seasonal influenza morbidity and mortality in the last 50 years, surpassing the impact of H1N1. Data assessing immunogenicity and safety of this virus component are lacking in systemic lupus erythematosus (SLE) and restricted to small reports with other H3N2 strains. OBJECTIVE: This study aims to evaluate short-term immunogenicity and safety of influenza A/Singapore (H3N2) vaccine in SLE. METHODS: 81 consecutive SLE patients and 81 age- and sex-matched healthy controls (HC) were vaccinated with the influenza A/Singapore/INFIMH-16-0019/2016(H3N2)-like virus. Seroprotection (SP) and seroconversion (SC) rates, geometric mean titers(GMT), and factor increase in GMT(FI-GMT) and adverse events were assessed before and 4 weeks post-vaccination. Disease activity and therapies were also evaluated. RESULTS: Before immunization, SLE and HC groups had high SP rates (89% vs 77%, p = 0.061) and elevated GMT titer with higher levels in SLE (129.1(104.1-154.1) vs 54.8(45.0-64.6), p < 0.001). Frequency of two previous years' influenza vaccination was high and comparable in SLE and HC (89% vs 90%, p = 1.000). Four weeks post-vaccination, median GMT increased for both groups and remained higher in SLE compared to HC (239.9(189.5-290.4) vs 94.5(72.6-116.4), p < 0.0001) with a comparable FI-GMT (2.3(1.8-2.9) vs 1.9(1.5-2.3), p = 0.051). SC rates were low and comparable for both groups (16% vs 11%, respectively, p = 0.974). Disease activity scores remained stable throughout the study (p = 1.000) and severe adverse events were not identified. CONCLUSION: Influenza A/Singapore (H3N2) vaccine has an adequate safety profile. The distinct immunogenicity pattern from other influenza A components characterized by a remarkably high pre- and post-vaccination SP rate and high GMT levels may be associated with previous influenza A vaccination. (www.clinicaltrials.gov, NCT03540823).