SARS-CoV-2 vaccination Immunity and disease activity in immune- mediated inflammatory diseases

During the SARS-Cov-2 pandemic, patients with immune-mediated inflammatory diseases (IMIDs) were faced with two pressing questions. Firstly, as these patients often use immunosuppressants, it was not known whether they would build sufficient immunity after a SARS-CoV-2 infection or vaccination. Secondly, IMID patients were concerned that vaccination could lead to increased disease activity of the IMID, as the safety of the vaccine was not evaluated in this population. In this thesis, we provide insights into these questions from a national prospective multicentre cohort study.
We observed that the humoral immune response after vaccination is present in most of the patients on immunosuppressants, although the antibody titre is generally lower, especially in patients on a combination of immunosuppressants. However, patients on anti-CD20 therapy, S1P-modulators, and mycophenolate mofetil show significantly reduced humoral responses with a high number of non-responders and very low antibody titres. Adding a vaccine dose to the basic series and repeated vaccination after the basic series may increase the response in these groups. We did not find a temporal relation between SARS-CoV-2 vaccination and increased disease activity on the population level, and proportions of increased and decreased disease activity after vaccination were comparable.
In summary, patients with specific immunosuppressants require additional immunisation to achieve an optimal humoral response and vaccination seems safe in patients with IMIDs regarding disease activity. These findings may aid patient and professional decision-making regarding SARS-CoV-2 vaccination, as well as provide guidance in future pandemics.