P3538 - Associations Between Body Mass Index and Serological Responses to SARS-CoV-2 Vaccination in Patients With Inflammatory Bowel Disease

Kenneth Ernest-Suarez, MD¹, Fiona Yeaman, MBBS¹, Joshua Quan, MSc¹, Catherine Rowan, MD¹, Christopher Ma, MD², Remo Panaccione, MD¹, Lindsay Hracs, PhD¹, Nastaran Sharifi, MD¹, Michelle Herauf, MSc¹, Ante Markovinović, BA¹, Stephanie Coward, PhD¹, Joseph W.. Windsor, PhD¹, Léa Caplan, BHSc¹, Richard J. M.. Ingram, MD, PhD¹, Cynthia Seow, MD¹, Kerri Novak, MD¹, Cathy Lu, MD, MSc¹, Gilaad G. Kaplan, MD, MPH^1
1University of Calgary, Calgary, AB, Canada; ²Alimentiv Inc., University of Calgary, London, ON, Canada

Introduction: Vaccines have been shown effective regardless of Body Mass Index (BMI), obesity may impact antibody levels compared to healthy weight subjects. The durability of vaccine response in people with obesity has not been definitively studied in those IBD. This study aims to determine the association between elevated BMI and serological responses (SR) to SARS-CoV-2 vaccination in individuals with IBD.

Methods: SARS-CoV-2 vaccinated (≥ 2 doses) adults with IBD were recruited from the STOP COVID-19 IBD cohort. Patient height and weight recorded at recruitment were used to calculate BMI. Individuals were stratified into “obese” (BMI ≥30) and “normal to overweight” (BMI 18.5-30) groups according to the CDC Obesity classification. IgG antibodies to the spike protein of SARS-CoV-2 (anti-S) were assessed using the Abbott Architect SARS-CoV-2 IgG II Quant assay at 1–8 weeks after 1^st dose vaccination, and 1–8 weeks and 8+ weeks after 2^nd, 3^rd, and 4^th dose vaccination. Sex, age, IBD type, and medication status at 1^st dose of vaccine were collected via chart review and compared between BMI groups using Chi-square tests for frequencies or Mann-Whitney U test for means. Positive SR (≥50 AU/mL) rates were compared between BMI groups using two-sample proportion tests. Anti-S concentrations, reported as geometric mean titres (GMT), were compared using Mann Whitney-U tests. For timepoints with significant GMT differences, multivariable linear regression was used to model the association between obesity and anti-S concentration, adjusted for age, sex, IBD type, medication class, and prior COVID-19 infection.

Results: 105 individuals have with obesity and 362 non-obese were recruited. SR rates were similar between groups across all vaccine doses. Anti-S titres were significantly increased for individuals with BMI ≥30 following 1–8 weeks post-3^rd dose vaccination (18721 vs. 11304 AU/mL). However, no significant GMT differences were observed for other timepoints (Table 1, Figure 1). This association between obesity and increased anti-S held after adjusting for confounders within a regression model (Geometric mean ratio: 1.61; 95% CI: 1.16, 2.22; p=0.004).

Discussion: Antibody levels in obese IBD patients were similar to non-obese with the exception of a higher initial response following 3^rd vaccine dose. Future studies are necessary to explore clinical, pharmacodynamic, or immunological factors explaining a higher SR in obese individuals with IBD, and whether this confers greater protection.



Disclosures:


Kenneth Ernest-Suarez, MD¹, Fiona Yeaman, MBBS¹, Joshua Quan, MSc¹, Catherine Rowan, MD¹, Christopher Ma, MD², Remo Panaccione, MD¹, Lindsay Hracs, PhD¹, Nastaran Sharifi, MD¹, Michelle Herauf, MSc¹, Ante Markovinović, BA¹, Stephanie Coward, PhD¹, Joseph W.. Windsor, PhD¹, Léa Caplan, BHSc¹, Richard J. M.. Ingram, MD, PhD¹, Cynthia Seow, MD¹, Kerri Novak, MD¹, Cathy Lu, MD, MSc¹, Gilaad G. Kaplan, MD, MPH¹. P3538 - Associations Between Body Mass Index and Serological Responses to SARS-CoV-2 Vaccination in Patients With Inflammatory Bowel Disease, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.