Several case–control studies in children suffering from various immune-mediated disorders (autoimmune hepatitis, IBD, and JIA) have observed a reduced immune response following HBV vaccine in children with immune-mediated disorders compared to healthy children and a decreased long-term antibody persistence, particularly in those treated with GCs, AZA, and anti-TNFα (68–71). This evidence concerns the gene TNF and juvenile idiopathic arthritis.