Inclusion Criteria:  Be of legal age (> 18 years). Diagnosis of inflammatory bowel disease (Crohn's Disease or Ulcerative Colitis). Complete vaccination schedule (one or two doses depending on previous SARS-Cov2 infection) between one and four months prior to the determination of anti-SARS-Cov2 antibodies. Treatment with biological therapy for at least 6 weeks prior to the time of vaccination for the group of patients treated with biological drugs.  Exclusion Criteria:  Last vaccination dose more than four months ago from the determination of antibodies against SARS-Cov2.