Adverse events of SARS-CoV-2 vaccination in patients with inflammatory rheumatic disease during repeated vaccination: An observational cohort study

To give further insights into the safety of SARS-CoV-2 vaccinations in patients with inflammatory rheumatic diseases (IRDs) compared to healthy individuals and to highlight changes over the course of repeated vaccinations. In this single-centre study, SARS-CoV-2 vaccinated IRD patients were recruited from the hospital of the University of Munich. Healthcare workers served as the control group. Adverse events following each vaccination were assessed using questionnaires. Descriptive statistics and non-parametric tests were used to illustrate the differences between IRD patients and the control group. Between January 1, 2021, and Septemper 30, 2022, 235 IRD patients (60.4% female) and 102 healthy individuals (66.7% female) were enrolled in this study. The frequency of patients who experienced adverse events after the first vaccination (140 [59.6%]) was significantly lower compared to the control group (86 [84.3%]) (OR = 0.274 [95% CI: 0.151-0.497]; P < 0.0001). The same was true after the second vaccination (patients: 138 [58.7%]; controls: 80 [78.4%]) (OR = 0.391 [0.228-0.670]; P < 0.001), and after the third vaccination (123 [56.4%]; 70 [69.3%]) (OR = 0.573 [0.348-0.946]; P = 0.029). Local side effects occurred with similar frequency in both groups. However, systemic effects occurred significantly less frequently in patients after all vaccinations than in controls (1. vaccination 97 [41.3%] to 61 [59.8%]: OR = 0.472 [0.294-0.759], P = 0.002; 2. vaccination 91 [38.7%] to 60 [58.8%]: OR = 0.442 [0.275-0.710], P < 0.001; 3. vaccination: 85 [39.0%] to 52 [51.5%]: OR = 0.602 [0.374-0.969], P = 0.036). SARS-CoV-2 vaccines were well tolerated by patients with IRDs. They experienced systemic side effects less frequently in patients than in healthy controls, suggesting a possible association between IRDs/immunosuppressive therapies and attenuation of vaccination reactions. Further research is needed to determine the cause of these differences.