ASIA syndrome after BNT162b2 vaccination: Is it a distinct rheumatoid arthritis phenotype?

Vaccines are an identified cause of autoimmune/inflammatory syndrome induced by adjuvants (ASIA syndrome). In this research, we aimed to investigate the remarkable features of patients, whom we classified as ASIA syndrome, developing rheumatoid arthritis (RA) after BNT162b2 vaccination. Patients who were asymptomatic before the BNT162b2 vaccination, developed chronic arthritis within 3 months after the vaccination, and fulfilled the 2010 American College of Rheumatology/European League Against Rheumatism RA classification criteria were enrolled in the study. Demographic, laboratory, clinical, and treatment characteristics were reviewed retrospectively. We identified ten patients developing RA following BNT162b2 vaccination. The median age was 54.5 years and six of them were female. The median time between vaccination and onset of symptoms was 7 days; seven patients had acute arthritis, and four had intermittent arthritis at the onset of the disease. Only three patients had a disease onset in the small joints of the hands. All patients had radiological erosions on hand X-rays. We reported a case series of patients, classifiable as having ASIA syndrome, who developed RA with radiological erosions after the BNT162b2 vaccine. The onset of the disease in joints different from the typically expected ones, along with the early development of erosions in hand X-rays, suggests that these cases may follow a course distinct from classic RA. RA that develops following mRNA vaccination may have an aggressive course, but studies with larger sample sizes are needed.