Investigators from 5 Dutch medical centers conducted a randomized open-label clinical trial to evaluate the immunogenicity and safety of the measles-mumps-rubella (MMR) booster vaccination in children with juvenile idiopathic arthritis (JIA) who had previously received their primary MMR vaccination. The study was conducted in patients 4 to 9 years old to allow patients in the nonvaccinated arm to receive their MMR booster on the normal schedule (age 9–10 years in Netherlands).
Patients who were on a biologic treatment for JIA (ie, etanercept, anakinra) had this treatment held for 5 half-lives before receiving the booster, and for an additional 3 to 7 days after receiving the vaccine. The primary outcome measure, JIA disease activity, was evaluated using the JADAS-27 measure, which is a composite score based on the following components: number of joints with active arthritis, physician global assessment of activity, patient overall global well-being score, and normalized ESR. Lower JADAS-27 scores are indicative of less disease activity. Secondary outcome measures included the number of flares that occurred during the 1-year follow-up. To assess the immunogenicity of the booster vaccination, the level of MMR-specific IgG antibodies was determined at 12 months after enrollment. Cut-off values for seroprotection against each disease were selected prior to patient enrollment; the proportion of participants with seroprotection in each treatment group 12 months after enrollment was compared.
A total of 137 JIA patients were randomized and outcome data evaluated in 131; 63 received MMR booster and 68 were randomized to no vaccination. Among the 131 study patients, 72 (55%) had the persistent oligoarthritis pattern of JIA, followed by the polyarticular subtype (21%); 11% had systemic JIA. Almost half of the patients were on methotrexate (MTX), and 11% were on a biologic agent (either TNF antagonist or interleukin-1 receptor antagonist). Children in both study arms had a low JADAS score at baseline, with most having no active joints. Participants in the 2 study arms were similar for mean age, disease duration, and JIA subtype pattern.
No significant change occurred in JADAS-27 during follow-up for either arm, or for patients on MTX or biologic treatment. Similar percentages of patients in each arm had a disease flare. Study patients randomized to the booster vaccination group had significantly higher MMR antibody concentrations at 12 months compared to controls, and tended to have a higher frequency of seroprotection against measles, rubella, and mumps than those in the control group (100%, 100%, 97%, and 92%, 94%, and 81%, respectively). There were no serious adverse effects related to MMR vaccination and no infections related to attenuated virus occurred, including in the 9 patients receiving biologic treatment.
The authors conclude that MMR booster vaccination did not lead to worse JIA disease activity and was immunogenic.