Decreased Immune Response to COVID-19 mRNA Vaccine in Patients with Inflammatory Bowel Diseases Treated with Anti TNFα

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 immune 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 (S) 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), and 73 HC. After the first vaccine dose all HC were seropositive, while some patients with IBD, regardless of treatment, remained seronegative. After the second dose all subjects were seropositive, however anti-S levels were significantly lower in anti-TNFα treated compared to untreated patients, and HC (p<0.001; p<0.001, respectively). Neutralizing and inhibitory functions were both lower in anti-TNFα treated compared to untreated patients, and HC (p<0.03; p<0.0001, respectively). Anti-TNFα drug levels and vaccine responses did not affect anti-S levels. Infection rate (~2%) and AEs were comparable in all groups. IBD activity did not change in response to BNT162b2. Conclusions: In this prospective study in patients with IBD stratified according to treatment all patients mounted an immune response to two doses of BNT162b2. However, its magnitude was significantly lower in patients treated with anti-TNFα, regardless of administration timing and drug levels. Vaccine was safe. As vaccine immune response longevity in this group may be limited, vaccine booster dose should be considered.