Safety and Immunogenicity of Yellow Fever 17D Vaccine in Adults Receiving Systemic Corticosteroid Therapy: An Observational Cohort Study

Objective To assess the safety and immunogenicity of live attenuated yellow fever (YF) 17D vaccine in adults receiving systemic corticosteroid therapy. Methods All adult travelers on systemic corticosteroid therapy who had received the YF17D vaccine in 24 French vaccination centers were prospectively enrolled and matched with healthy controls (1:2) on age and history of YF17D immunization. Safety was assessed in a self‐administered standardized questionnaire within 10 days after immunization. YF‐specific neutralizing antibody titers were measured 6 months after vaccination in patients receiving corticosteroids. Results Between July 2008 and February 2011, 102 vaccine recipients completed the safety study (34 receiving corticosteroids and 68 controls). The median age was 54.9 years (interquartile range [IQR] 45.1–60.3 years) and 45 participants had a history of previous YF17D immunization. The median time receiving corticosteroid therapy was 10 months (IQR 1–67 months) and the prednisone or equivalent dosage was 7 mg/day (IQR 5–20). Main indications were autoimmune diseases (n = 14), rheumatoid arthritis (n = 9), and upper respiratory tract infections (n = 8). No serious adverse event was reported; however, patients receiving corticosteroids reported more frequent moderate/severe local reactions than controls (12% and 2%, respectively; relative risk 8.0, 95% confidence interval 1.4–45.9). All subjects receiving corticosteroids who were tested (n = 20) had neutralizing antibody titers >10 after vaccination. Conclusion After YF17D immunization, moderate/severe local reactions may be more frequent in patients receiving systemic corticosteroid therapy. Immunogenicity seems satisfactory. Large‐scale studies are needed to confirm these results.