Background Patients with inflammatory bowel diseases (IBD), specifically those treated with anti-tumor-necrosis-factor (TNF)α biologics are at high risk for vaccine preventable infections. Their ability to mount adequate vaccine responses is unclear. Aim To assess serologic responses to mRNA-COVID-19 vaccine, and safety profile, in patients with IBD stratified according to therapy, compared to healthy controls (HC). Methods Prospective, controlled, multi-center Israeli study. Subjects enrolled received two BNT162b2 (Pfizer/BioNTech) doses. Anti-spike antibodies levels and functional activity, anti-TNFα levels and adverse events (AEs) were detected longitudinaly. Results Overall 258 subjects: 185 IBD (67 treated with anti-TNFα, 118 non-anti-TNFα), and 73 HC. After the first vaccine dose all HC were seropositive, while ∼7% of patients with IBD, regardless of treatment, remained seronegative. After the second dose all subjects were seropositive, however anti-spike levels were significantly lower in anti-TNFα treated compared to non-anti-TNFα treated patients, and HC (both P
Graphical abstract