ABSTRACT
Background: The immune response of SARS-CoV-2 vaccines is uncertain in those with Inflammatory Bowel Disease (IBD) due to a diverse array of immune-modifying therapies that vary in the mechanism of immunosuppression. Aim: We aimed to quantify the serological response to SARS-CoV-2 vaccines in those with IBD and determine antibody levels across varying therapeutic options. Methods: Individuals with IBD who received a first and/or second dose of a COVID-19 vaccine (Pfizer-BioNTech, Moderna, and/or AstraZeneca) were assessed for serological response (1–8 weeks after first dose;1–8 weeks after second dose, 8–18 weeks after second dose, 18+ weeks after second dose) using the SARS-CoV-2 IgG II Quant assay to the receptor-binding domain of the SARS-CoV-2 spike protein. The cohort was stratified based on age, sex, vaccine received, IBD type, IBD therapeutic, and prior confirmed diagnosis of COVID-19. The primary outcome was seroconversion defined as IgG levels of ³50 AU/mL. Secondarily, we evaluated the geometric mean titer (GMT) with 95% confidence intervals (CI). Results: Table 1 describes the characteristics of individuals with IBD (n=466) with serological data following the first dose (n=247) and/or second dose (n=413) of a COVID-19 vaccine. After 1–8 weeks following first dose of the vaccine, 81.4% seroconverted, with the lowest first-dose conversion rates in patients taking anti- TNF monotherapy (80.3%), anti-TNF combination therapy (51.5%), and corticosteroids (50.0%) (Table 1). Overall, 98.4% of the cohort seroconverted within 1–8 weeks of the second dose. Over time, seropositive rates decreased with 95.8% seroconversion within 8– 18 weeks of the second dose and 90.5% after 18 weeks. Seroconversion after second dose was consistently high across all medication classes (range: 94.6%–100.0%), except for oral corticosteroids (62.5%). GMT levels significantly increased (p<0.0001) from first dose (1825 AU/mL [95% CI: 981, 2668 AU/mL]) to second dose at 1–8 week (9059 AU/mL [7698, 10420 AU/mL]) but fell significantly (p<0.0001) to 3649 AU/mL (95% CI: 2562, 4736 AU/ mL) 8–18 weeks from second dose and 2527 AU/mL (95% CI: 883, 4172 AU/mL) 18+ weeks after second dose (Table 1, Figure 1). GMT levels 1–8 weeks after second dose were higher in those with prior COVID-19 (16,770 AU/mL), but lower in those receiving anti- TNF combination therapy (4231 AU/mL) and oral corticosteroids (5996 AU/mL) (Table 1). Conclusion: Seroconversion rates following full-regimen vaccination are high in patients with inflammatory bowel disease across all medication classes except for anti-TNF combination therapy and oral corticosteroids. Antibody titres and seroconversion rates tend to decrease after eight weeks post-full vaccination, which is consistent across medication classes. (Table Presented) Table 1. Patient and vaccine characteristics, seroconversion rates, and geometric mean titres by prior PCR-confirmed COVID-19 status for each medication class. (Figure Presented) Figure 1. Log-transformed anti-SARS-CoV-2 spike antibody concentration per vaccine category. Black points represent GMTs while narrow black bars represent bounds of 95% CI associated with each GMT. Solid blue line represents threshold for positive seroconversion [ln (50 AU/mL)].
ABSTRACT
Background: The immune response to a two-dose regimen of SARS-CoV-2 vaccination in those with Inflammatory Bowel Disease (IBD) has been consistently high in emerging research. Serological responses following a third dose have yet to be established. Aim: We aimed to quantify the serological response to a third dose of SARS-CoV-2 vaccines in those with IBD and compare to responses after a two-dose regimen. Methods: Individuals with IBD who have received at least two doses of a COVID-19 vaccine were assessed for serological response using the SARS-CoV-2 IgG II Quant assay to the receptor-binding domain of the SARSCoV- 2 spike protein at least eight weeks after second dose and then after third dose. The primary outcome was seroconversion defined as IgG levels of ≥50 AU/mL. Secondarily, we evaluated the geometric mean titer (GMT) with 95% confidence intervals (CI). Outcomes were stratified by prior COVID-19 history. A Wilcoxon rank sum test was used to compare antibody titres following 3rd dose vaccination and titres following 2nd dose vaccination. For patients with both post-2nd and post-3rd vaccination serology, the difference in antibody titres between doses was determined and the mean difference was tested using one-sample Student's t-tests. Results: Table 1 describes the characteristics of individuals with IBD (n = 271) with serological data following the corresponding dose for those with 2nd dose vaccination (n = 175) compared to those with a 3rd dose of vaccine (n = 96). Seroconversion following 3rd dose vaccination occurred for all individuals (100.0%), compared to a 94.4% seroconversion rate at least eight weeks following 2nd dose vaccination (range: 8 to 35 weeks post-2nd dose). GMT for the post-3rd dose cohort (16424 AU/mL [13437, 19411 AU/mL]) was significantly higher (p<0.0001) than the post-2nd dose cohort (3261 AU/mL [2356, 4165 AU/mL] (Table 1, Figure 1b). Individual titres as a function of time following 2nd dose vaccination are seen in Figure 1a for both 3rd dose and 2nd dose cohorts. For individuals with serology following both 2nd dose and 3rd dose vaccination (n = 82), seroconversion rates increased from 97.6% to 100.0% after the 3rd dose. GMT following post-3rd dose vaccination also increased with a mean difference in antibody titres between post-3rd dose and post-2nd dose vaccination of 11384 AU/mL (8541, 14228 AU/mL, p < 0.0001). This difference was significant for both individuals with prior COVID-19 history (11682 AU/mL [95% CI: 8618, 14746 AU/mL, p<0.0001]) and individuals without (8194 AU/mL [95% CI: 988, 15400 AU/mL]). Conclusion: Seroconversion rates and antibody response following third dose vaccination are substantially increased as compared to second dose in patients with IBD. Third dose vaccination can counter the decrease in antibody concentration over time following a two-dose regimen. (Table Presented) Table 1. Patient characteristics, vaccine type, seroconversion rates, and geometric mean titres by prior COVID-19 status for post-3rd dose and post-2nd dose cohorts
ABSTRACT
BACKGROUND: The immune response of SARS-CoV-2 vaccines is uncertain in those with Inflammatory Bowel Disease (IBD) due to a diverse array of immune-modifying therapies that vary in the mechanism of immunosuppression. AIM: We aimed to quantify the serological response to SARS-CoV-2 vaccines in those with IBD and determine antibody levels across varying therapeutic options. METHODS: Individuals with IBD who received first and/or second dose of a COVID- 19 vaccine (Pfizer-BioNTech, Moderna, and/or AstraZeneca) were assessed for serological response (2-4 weeks after first dose;2-8 weeks after second dose and 8-18 weeks after second dose) using the SARS-CoV-2 IgG II Quant assay to the spike protein of SARS-CoV-2. The cohort was stratified based on age, sex, vaccine received, IBD type, IBD therapeutic, and prior confirmed diagnosis of COVID-19. The primary outcome was seroconversion defined as IgG levels of ≥50 AU/mL. Secondarily, we evaluated the geometric mean titer (GMT) with 95% confidence intervals (CI). RESULTS: Table 1 describes the characteristics of individuals with IBD (n=464) with serological data following the first dose (n=266) and/or second dose (n=303) of a COVID-19 vaccine. After the first dose of the vaccine, 81.6% seroconverted, with the lowest first-dose conversion rates in patients taking anti-TNF monotherapy (79.7%), anti-TNF combination therapy (52.9%), and corticosteroids (50.0%) (Table 1). Overall, 98.4% of the cohort seroconverted within 2-8 weeks of the second dose, with 94.6% seropositive within 8-18 weeks of the second dose. Seroconversion after second dose was consistently high across all medication classes (range: 94.6%-100.0%), except for oral corticosteroids (62.5%). GMT levels significantly increased (p<0.0001) from first dose (1679 AU/mL) to second dose at 2-8 week (7943 AU/mL) but fell significantly (<0.0001) to 3565 AU/mL 8-18 weeks from second dose (Table 1, Figure 1). GMT levels 2-8 weeks after second dose were higher in those with prior COVID-19 (12,729 AU/mL), but lower in those receiving anti-TNF combination therapy (4231 AU/mL) and oral corticosteroids (5996 AU/mL) (Table 1). CONCLUSION: Seroconversion rates following fullregimen vaccination are high in patients with inflammatory bowel disease across all medication classes except for anti-TNF combination therapy and oral corticosteroids. Antibody titres and seroconversion rates tend to decrease after 8 weeks postfull vaccination, which is consistent across medication classes.