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. The aim of the study was to assess serologic responses to messenger RNA–Coronavirus Disease 2019 vaccine, and safety profile, in patients with IBD stratified according to therapy, compared with healthy controls (HCs).

Prospective, controlled, multicenter Israeli study. Subjects enrolled received 2 BNT162b2 (Pfizer/BioNTech) doses. Anti-spike antibody levels and functional activity, anti-TNFα levels and adverse events (AEs) were detected longitudinally.

Overall, 258 subjects: 185 IBD (67 treated with anti-TNFα, 118 non–anti-TNFα), and 73 HCs. After the first vaccine dose, all HCs were seropositive, whereas ∼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 with non–anti-TNFα treated patients, and HCs (both P < .001). Neutralizing and inhibitory functions were both lower in anti-TNFα treated compared with non–anti-TNFα treated patients, and HCs (P < .03; P < .0001, respectively). Anti-TNFα drug levels and vaccine responses did not affect anti-spike levels. Infection rate (∼2%) and AEs were comparable in all groups. IBD activity was unaffected by BNT162b2.

In this prospective study in patients with IBD stratified according to treatment, all patients mounted serologic response to 2 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 serologic response longevity in this group may be limited, vaccine booster dose should be considered.