The vaccination of immunocompromised children against coronavirus disease 2019 is an important public health issue. We evaluated the serological response, safety, and efficacy of the BNT162b2 vaccine in children with and without inflammatory bowel disease (IBD). A prospective, multicenter, case-control study was conducted in a pediatric population, including patients with IBD, aged 12-18 years. Clinical characteristics, safety profile, and serum samples for surrogate virus-neutralizing antibody testing pre- and post-BNT162b2 vaccination were assessed. The breakthrough infection rate during the Omicron outbreak was calculated to evaluate efficacy. Fifteen controls and twenty-three patients with IBD were enrolled. After two vaccine doses, the median level of percentage inhibition was highly increased, without significant differences between the groups (control 96.9 and IBD 96.3). However, it was significantly reduced in IBD patients receiving combination therapy (anti-tumor necrosis factor-α + immunomodulators) relative to those in other therapies and controls. Serious adverse events were not observed. The breakthrough infection rate was 42.1%, without statistical differences between the groups. Immunization with BNT162b2 in patients with IBD was comparable with that in healthy adolescents in terms of immunogenicity and safety. Nevertheless, the efficacy of BNT162b2 in preventing infection caused by the Omicron variant in the pediatric population was insufficient.
Keywords: COVID-19 breakthrough infections; COVID-19 vaccines; adolescent; inflammatory bowel diseases; pediatric.