Objective: To assess the effect of measles, mumps and rubella (MMR) vaccination on disease activity in children with juvenile idiopathic arthritis (JIA).
Methods: A retrospective observational multicentre cohort study was performed in 314 patients with JIA, born between 1989 and 1996. Disease activity and medication use were compared during the period of 6 months before vaccination versus 6 months after vaccination. Disease activity was measured by joint counts, the Physician's global assessment scale and erythrocyte sedimentation rate. Next, we compared disease activity in patients vaccinated between 8 and 9 years of age with the activity in patients who had not been vaccinated at this time (who received MMR between the ages of 9 and 10 years).
Results: No increase in disease activity or medication use was seen in the 6 months after MMR vaccination (n = 207), including in patients using methotrexate (n = 49). No overt measles infections were noted. When disease activity in vaccinated patients (n = 108) was compared with activity in those not yet vaccinated (n = 86), there were no significant differences.
Conclusions: The MMR booster vaccination does not seem to aggravate disease activity in JIA. This indicates that the most patients with JIA can be vaccinated safely with the MMR vaccine. A prospective study is recommended.