Aim
To analyze the clinical patterns of new‐onset inflammatory arthritis after COVID‐19 vaccination among patients without pre‐existing rheumatic or autoimmune diseases.
Method
Case reports and series of new‐onset inflammatory arthritis after COVID‐19 vaccination were collected before April 2022. Clinical characteristics including diagnosis, age, gender, vaccine types, time interval between events, joint involvement (poly‐ or oligo−/monoarthritis), and laboratory data reflecting inflammatory status were sorted and
P
values between these parameters are calculated with independent sample Student's
t
test or 2 × 2 Fisher's exact test.
Results
Among 39 cases with new‐onset post‐vaccination arthritis including 25 females and 13 males (1 unknown), the most common diagnosis is adult‐onset Still's disease (AoSD, 10 cases), and the most common vaccine types are BNT162b2 (16 cases) and AZD‐1222 (or ChAdOx1‐nCoV19, 15 cases). Sub‐analysis reveals that post‐vaccination polyarthritis is more common among females (
P
= .016, by 2 × 2 Fisher's exact test, compared with male patients) and older patients (
P
= .006, by Student's
t
test). The C‐reactive protein level is significantly higher in cases with post‐vaccination inflammatory polyarthritis than oligoarthritis (
P
= .029), as well as in cases with AoSD than other causes of post‐vaccination arthritis (
P
= .004). However, serum level of erythrocyte sedimentation rate in patients with post‐vaccination AoSD are independent of other clinical variables in the analysis.
Conclusion
New‐onset post‐vaccination polyarthritis are more common in females and older patients. Although COVID‐19 vaccines may lead to inflammatory arthritis, the benefits of vaccination substantially outweigh the potential risks of such serious adverse effects due to their rarity.