Immunological efficacy and safety of influenza vaccination in adults with sarcoidosis: the SARCOVAC study

BACKGROUND: Half of patients with sarcoidosis have significant organ involvement and require long-lasting immunosuppressive treatment. We aimed to evaluate safety and immunological efficacy of a trivalent inactivated influenza vaccine in patients with sarcoidosis compared with healthy controls. METHODS: The SARCOVAC trial was an open-label, multicenter, prospective clinical trial. Influenza vaccination was performed in 2012-2013 in patients with both sarcoidosis and an indication for influenza vaccination, and in healthy controls. Antibody titers against A/H1N1, A/H3N2, and B influenza virus antigens were measured immediately before and 21 and 180 days after vaccination. The primary outcome was the comparison of seroconversion rates for each viral strain at day 21 between patients and controls. FINDINGS: We recruited 191 participants among whom 182 (83 patients, 99 controls) were included in the analysis. At D21, seroconversion rates were higher in patients than in controls for A/H1N1 strain (62.2% versus 45.4%, p = 0.025), and A/H3N2 strain (58.5% versus 35.1%, p = 0.002) but did not differ for B strain (72% versus 60.8%, p = 0.118). Seroprotection rates ranged between 73.2% and 90.7% at D21 and 59.4% and 79.4% at day 180 in patients and controls, respectively, with no statistical difference. The vaccination did not significantly impact the course of sarcoidosis. No difference in reactogenicity was found between patients and healthy controls. INTERPRETATION: Influenza vaccination is immunogenic in patients with sarcoidosis, including those with severe disease and immunosuppressive therapy. These results support the recommendations for influenza vaccination in patients with sarcoidosis who are at high risk of severe infections.