Live attenuated MMR/V booster vaccines in children with rheumatic diseases on immunosuppressive therapy are safe: Multicenter, retrospective data collection

Purpose: To collect retrospective data of patients with Juvenile Idiopathic Arthritis (JIA) and other rheumatic diseases who received live attenuated booster measles-mumps-rubella (MMR) or measles-mumps-rubellavaricella (MMR/V) during treatment with immunosuppressive therapy. Results: Data from 13 pediatric rheumatology centers in 10 countries, including 234 patients, were collected. Mean age at diagnosis was 5 ± 2.7 years, 67% were girls. Among them, 211 (90.2%) had JIA and 110 (47%) were in remission on medication. Disease activity was low in 37%, high in 8%, and moderate in 8%. One hundred-twenty-four receivedMMR/V booster while on methotrexate (MTX); 3 reported local mild adverse events (AE). Among 62 on MTX + biologics and 9 patients who received a combination of 2 disease modifying antirheumatic drugs (DMARDs), 9 reported mild AE. Among 39 on biologics, 1 reported fever one day after booster vaccination. No vaccine-related infection of measles, rubella, mumps or varicella was reported, none of the patients developed disease flare, including those with high disease activity. Conclusions: In this retrospective study, live-attenuatedMMR/V booster vaccines were safe for children with rheumatic diseases, on immunosuppressive therapies. This strengthens the Paediatric Rheumatology European Society (PReS) recommendation that vaccination with live attenuated vaccines in patients on immunosuppressive therapies can be considered individually, weighing the benefit of vaccination against the risk of inducing infection through vaccination. These data provide the basis for a prospective data collection study, planned by the PReS vaccination study group.