Juvenile idiopathic arthritis (JIA) has a prevalence between 16 and 150 per 100,000 population. The immunosuppressive effect of JIA and its treatment is associated with a susceptibility to infection. Effective and safe vaccinations that induce protective immune responses, have no severe adverse effects, and have no effect on JIA disease activity are needed to prevent infections in patients with JIA.
Children worldwide receive the live attenuated measles-mumps-rubella (MMR) vaccine via national immunization programs (NIPs). The safety of MMR vaccination has been questioned in patients with JIA because small uncontrolled studies have found an association between the rubella component and the induction of arthritis. This association has not been established in controlled trials, but concerns remain about the effect of MMR vaccination on JIA disease activity.
Researchers recently conducted a randomized clinical equivalence trial designed to examine whether MMR booster vaccination affects disease activity in patients with JIA. The trial also attempted to describe the humoral immune response induced by MMR booster vaccination. The results of the study were reported in JAMA [2012;309(23):2449-2456].
The trial included 137 patients with JIA 4 to 9 years of age recruited from 5 academic hospitals in the Netherlands between May 2008 and July 2011. The MMR booster is routinely administered via the NIP at 9 to 10 years of age. The patients were randomized to receive MMR booster vaccination (n=68) or no vaccination (control group) (n=69).
The primary outcome measure was disease activity as measured by the Juvenile Arthritis Disease Activity Score (JADAS-27). JADAS-27 scores range from 0 (no activity) to 57 (high activity). The trial compared disease activity in the year following randomization between revaccinated patients and controls. The equivalence margin was established as a 2.0 difference in JADAS-27.
Baseline characteristics were similar between the 2 groups with the exception of lower seroprotection rates against rubella in the MMR booster group compared with the control group. Nine patients in the MMR booster group were taking biologics; 2 of which took oral glucocorticoids concomitantly.
There was no significant difference in mean JADAS-27 during the total follow-up period between patients in the MMR booster group and those in the control group. This finding was true for patients taking methotrexate and biologics and for various JIA subtypes.
The mean number of flares per patient did not differ significantly between the MMR booster group and the control group (0.44 vs 0.34, respectively), nor did the percentage of patients with ≥1 flare during follow-up. The relative risk of a flare in revaccinated patients compared with controls was 0.9 at 3 months and 1.3 during total follow-up.
At 3 months following vaccination, increased antibody concentrations against measles, mumps, and rubella were detected in revaccinated patients. At 12 months following vaccination, antibody concentrations were significantly higher compared with controls against measles, mumps, and rubella.
No measles, mumps, or rubella disease occurred in revaccinated patients. In the control group, 1 patient presented with acute-onset parotitis at 12 months after inclusion, but laboratory testing for mumps was not performed. The patients had protective mumps-specific antibody levels at baseline.
In summary, the researchers said, “Among children with JIA who had undergone primary immunization, MMR booster vaccination compared with no booster did not result in worse JIA disease activity and was immunogenic.”