Abdulla Watad et al.

We evaluated IMD flares or new disease onset within 28-days of SARS-CoV-2 vaccination at five large tertiary centres in countries with early vaccination adoption, three in Israel, one in UK, and one in USA. We assessed the pattern of disease expression in terms of autoimmune, autoinflammatory, or mixed disease phenotype and organ system affected. We also evaluated outcomes.

… Numerically, our findings show the clearest associations for the non-specific adjuvant effects of the mRNA vaccines in triggering a host of different inflammatory disorders. It is possible that there is increased vigilance towards, and documentation of non-arthritis RMDs, since these are more likely to require specialist review, other investigations, or hospital treatment. Nevertheless, the proportion of the events observed is disproportionate to the usual frequency of these diseases. Usual prevalence would predict RA most commonly, followed by other inflammatory arthritis, and, then, non-arthritis RMDS. Here, we found that almost half of the events occur as forms of non-arthritis RMDs—usually far less frequent than inflammatory arthritis. Within inflammatory arthritis, spondyloarthropathy- spectrum disease was more frequent than RA, again differing from the usual prevalence, while one RA case had a usually-rare extra-articular feature. This suggests, although does not prove, causality. Most of the reported disease were flares, which supports the idea of the delicate balance of immune homeostasis in such cases being momentarily tipped into a pro-inflammatory state by vaccination.