Seroprevalence of ANTI-SARS-CoV-2 antibodies in patients with inflammatory bowel disease.

Patients with inflammatory bowel disease (IBD) treated with biologic and/or immunosuppressant drugs are at increased risk for opportunistic infections. Seroprevalence studies can confirm the diagnosis of SARS-CoV-2 infections as well as the associated risk factors. This is a descriptive study which primary endpoints were to highlight the prevalence of SARS-CoV-2 antibodies in a cohort of IBD patients in March 2021, and to analyze seroconversion in patients with known COVID-19 infection and its relationship with IBD treatments. Patients filled in a questionnaire about symptoms of COVID-19 infection and clinical information about their IBD. All included patients were tested for SARS-CoV-2 antibodies. 392 patients were included. Among patients with clinical infection, 69 patients (17,65%) were IgG-positive, 286 (73,15%) IgG-negative and 36 (9,21%) indeterminate. In relation to seroconversion among patients under biologic treatment, 13 patients of the 23 with a previous positive CRP developed antibodies (56.5%). However, when the influence of immunosuppressive treatment on the probability of developing antibodies was analyzed, no significant differences were seen between those patients with or without treatment (77.8% vs. 77.1%, p = 0.96). In our cohort of IBD patients, after one year of pandemic, there were 18.64% IgG positive patients, a higher prevalence than the general population (15.7%).

Serum prevalence of SARS-COv2 antibodies in patients with inflammatory bowel disease before vaccination

Introduction: Patients with inflammatory bowel disease (IBD) treated with biologic and/or immunosuppressant drugs are at increased risk for opportunistic infections, including viral infections (1) Previous studies have postulated that patients with IBD were not at increased risk of severe SARS-CoV-2 infections (2) although given the absence of microbiological confirmation at the onset of the pandemic, past infection could not be confirmed. Seroprevalence studies can confirm the diagnosis of SARS-CoV-2 infections as well as the associated risk factors. Aims & Methods: This is a descriptive study which primary endpoint was to highlight the prevalence of SARS-CoV-2 antibodies in a cohort of patients diagnosed with IBD followed in our unit, between 26 February and 26 March 2021, one year after the start of the pandemic. Patients with scheduled on-site visits to our unit were included;they filled in a detailed questionnaire about symptoms of COVID-19 infection, demographic data and clinical information about their IBD. All included patients were tested for SARS-CoV-2 antibodies by ELISA. Results: 338 patients were included: 181 with a diagnosis of Crohn's disease, 132 with ulcerative colitis and 25 with indeterminate colitis;baseline characteristics are shown in Table 1. There were 74 patients with clinically suspected infection compared to 264 without compatible clinical features. Among patients with clinical infection, 63 patients (18,64%) were IgG-positive, 243 (71,89%) IgG-negative and 32 (9,47%) indeterminate;These results were compared with the prevalence data of the Spanish Government in the community of Madrid (IgG positive 15,7%);differences were not statistically significant (p<0.05) (5). The positivity rate was analysed according to the treatment received. At the beginning of the pandemic, there were 46 patients without treatment (serological positivity rate 13,04%), 90 patients receiving mesalazine (IgG positive 27,78%), 51 patients receiving immunomodulators (IgG positive 27,45%), 85 patients with biological treatment (IgG positive 17,64%) and 56 patients combined biological and immunosuppressive treatment (serological positivity rate 5,36%).);these results were statistically significant (p <0,05). It is difficult to establish whether these differences between treatments are due to a lower number of infections (more patient care in the immunocompromised groups) or a lower seroconversion rate. (Table Presented) Conclusion: Although SARS-CoV-2 infection has been a diagnostic challenge in some cases, the presence of antibodies by ELISA allows confirmation of past infection. In our cohort of IBD patients, after one year of pandemic, there were 18.64% IgG positive patients, a higher prevalence than the general population (15.7%) (4). These differences may be justified by a higher number of hospital visits, the inflammatory disease itself or the treatments received.