P330 Immunity in patients with inflammatory bowel disease on biologic therapy after COVID 19 vaccination

Knezevic, T.(1);Cujic, D.(2);Odanovic, O.(1);Kralj, D.(1);Gnjatovic, M.(2);Kalaba, A.(1);Vrinic Kalem, D.(1);Svorcan, P.(1,3);Markovic, S.(1,3);

(1)University Hospital Zvezdara, Gastroenterology and hepatology, Belgrade, Serbia;(2)Institute for Application of Nuclear Energy, University of Belgrade, Belgrade, Serbia;(3)School of Medicine, University of Belgrade, Belgrade, Serbia;


IBD patients, especially on immunosuppressive therapy, are in high-risk of developing infections, the outbreak of the SARS-CoV-2 pandemic, made us approach to the whole situation with special caution. At beginning, we wondered if these patients were at increased risk of developing severe COVID19 infection. Knowledge and experience, in this area have progressed, however, with the beginning of vaccination a new question has arisen about what the humoral response to the vaccine would be in these patients.  

In Serbia 3 different types of vaccines from 4 manufacturer (Pfizer-BioNTech, AstraZeneca/ ChAdOxl nCoV-l9 COVISHIELD, SARS-CoV-2 Vero Cell, SPUTNIK V Gam-COVID-Vac) were available and the aim was to evaluate presence of neutralization antibodies after immunization against SARS-CoV-2.


328 patients with IBD, from a single tertiary IBD center, were asked about immunization against SARS-CoV-2 during treatment with biologic therapy (anti-TNF, anti-integrin- Vedolizumab) with two doses of available vaccines. Patients who were immunized were selected and analyzed on SARS-Cov-2 IgG response which was measured using ELISA anti-spike protein-based serology (INEP, Belgrade, Serbia) with cut off level of 15 as negative, 15-20 intermediate, and > 20 as positive.


From 328 patients, 61.5% (202/328) patients had CD, and 38.1% (125/328) had UC. Gender distribution was relatively equal, 53.6% men (176/328), with an average age of 55.7 (SD ±15.1) years. From those patients 25 were excluded because biologic therapy was stopped. On ADA were 105 patients, IFX were 91, VDZ 106. From 303 patients 58.08% (176/303) were vaccinated (with Pfizer-BioNTech COVID-19 59 patients, AstraZeneca/ChAdOxl nCoV-l9 COVISHIELD 9 patients, SARS-CoV-2 Vero Cell 97 patients and SPUTNIK V Gam-COVID-Vac 11 patients). In 16 patients IgG antibodies weren’t measured because they were vaccinated after IgG were measured. From 160 patents 31.2 % (50/160) didn’t have detectable IgG antibodies and that is in 5 patients vaccinated with Pfizer-BioNTech COVID-19, 43 patients with SARS-CoV-2 (Vero Cell) and in 2 patients with SPUTNIK V Gam-COVID-Vac. When we look in contest of therapy. IgG antibodies were detectable in 53.9% (34/63) from 63 vaccinated patients on VDZ and in 53.06% (52/98) from 98 vaccinated patients on anti TNF.


In patients with inflammatory bowel disease on biologic therapy from February to September 2021 rate of immunization were satisfying with more than 50% vaccinated patients with detectable IgG antibodies in 68.6% of patients with highest neuralization IgG antibodies present after immunization with Pfizer-BioNTech COVID-19 vaccine, however further studies are needed to determine efficacy of each vaccine.