Safety of the BNT162b2 mRNA COVID-19 vaccine in children and adolescents with juvenile idiopathic arthritis: a tertiary-center early experience

Background Research on the COVID-19 vaccination in patients with underlying rheumatic disorders in pediatric age is lacking. We studied possible adverse events of the mRNA BNT162b2 vaccine against SARS-CoV-2 (Pfizer-BioNTech) in children and adolescents with juvenile idiopathic arthritis (JIA), and also if there is a risk of flaring of the underlying JIA. We reported 36 JIA patients aged 5-18 years old received 2 doses of the COVID-19 vaccine (72 doses). Patients were followed before and after vaccination, and any related adverse event was recorded. JIA disease activity was assessed using Juvenile Arthritis Disease Activity Score-10 (JADAS-10) before and after vaccination. Results Among 72 doses of the vaccine received, local adverse events (AEs) were reported by majority of the patients (66.7%); most commonly reported local AE was pain at the site of injection. Systemic AEs were revealed by (65.3%), most commonly reported systemic AEs were tiredness, myalgia, and headache. Almost all the reported AE were mild to moderate and resolved within 1-2 days and were also more frequently noted after the second dose. No flaring of the underlying primary rheumatic disease after vaccination. No one of the study group revealed serious adverse events. Conclusions This is one of the early studies reporting that mRNA COVID-19 vaccine seems to be safe in children and adolescents with JIA. Almost all the reported adverse events were mild to moderate and transient. Also, no serious adverse events or flaring of the primary disease were reported.