ABSTRACT
Background: COVID-19 vaccination strategies have evolved with increasing vaccine availability and emerging vaccine safety data. While data on immuno-genicity and safety of COVID vaccination strategies exists, there is limited data for people with immune mediated infammatory diseases (IMIDs) such as infam-matory arthritis (IA), systemic autoimmune rheumatic disease (SARD), infam-matory bowel disease (IBD) and multiple sclerosis (MS). Objectives: In IMID patients treated with homologous or heterogeneous COVID vaccines, to compare post vaccine IMID disease activity and COVID antibody responses. Methods: Between March 2021 and Dec 2021, patients with IA (n= 70;77% rheumatoid arthritis), SARD (n=82;70% lupus), IBD (n= 92;40% crohn's), and MS (n= 71;77% RRMS) self-reported COVID illness and exposure risks, and disease activity prior to and 1 month post both COVID-19 vaccinations (V1 and V2). Disease activity was assessed by the Systemic Lupus Activity Questionnaire (SLAQ) for SARDs, the RAPID-3 and RA fate index for IA, the IBD Symptoms Inventory-short form (IBDSI) and IBD fare index for IBD and the 25 meter walk and 9 hole peg test and Expanded Disability Status Scale (EDSS) for MS. Patient reported fare state was assessed using the relevant questions these indices (SLAQ 'Have you had a fare?';RA Flare index 'Are you in a fare?';IBD fare 'My IBD is sometimes to continously active'). Disease activity and serum anti-spike, anti-receptor binding domain (RBD) and anti-nucleocapsid (NC) IgG antibody titers at 30 days post V2 were compared across vaccine courses and to age-sex matched vaccinated blood donor controls (CNTS). Results: Patients were predominantly female (79.7%), with a mean (standard deviation-sd) age of 56 (15) years;8% had suspected or diagnosed COVID-19 illness;1.2% positive anti-NC (Table 1). For all IMIDS, the majority received mRNA vaccines-BNT162b2 (BNT) or mRNA1273 (V1 74%;V2 97%;) the rest received ChAdOx1 viral vector vaccines;71% received homologogous vaccines (ChAdOx1-ChAdOx n=6;BNT-BNT n=174;mRNA1271-mRNA1273 n=21;ChAdOx1-BNT n=36;ChAdOx1-mRNA1273 n=30;BNT-mRNA1273 n=15;mRNA1273-BNT n=3;other n=4). For most IMIDs, disease activity was similar before and after each vaccination. Post V2 disease activity did not differ between homologous versus heterologous vaccines nor by vaccine type (RAPID3;SLAQ, 25 meter walk and 9 hole peg test and EDSS overall and subscales, IBDSI overall and subscales all p=NS). In 254 IMIDs, most seroconverted (anti-spike 86%;anti-RBD 96%). Seroconversion rates for CNTS were 98.1% for anti-Spike and 3.5% for anti-NC. Antibody titers were higher following homologous mRNA (BNT or mRNA12723) than homologous vector vaccine (Figure 1). For IMIDs primed with ChAdOx vector vaccine, boosting with BNT or mRNA1273 generated similarly increased anti-Spike and anti-RBD titers. Conclusion: Heterologous COVID vaccination improves seroconversion rates following a viral vector vaccine and does not lead to disease fare in most IMID patients. While data is needed to assess vaccine effectiveness, duration of immu-nogenicity and effects of subsequent vaccination, this work supports mixing COVID vaccines for IMID patients.