Longitudinal safety and efficacy of the BNT162b2 mRNA COVID-19 vaccine in children aged 4-11 years with juvenile-onset autoimmune inflammatory rheumatic diseases: A prospective multicenter study

This prospective, longitudinal, multicenter study assessed the safety and efficacy of the Pfizer-BioNTech BNT162b2 mRNA COVID-19 vaccine among children 4-11 years-old with autoimmune inflammatory rheumatologic disease (AIIRD), compared to healthy controls. The study was conducted from 11/2021-12/2022 at 4 tertiary pediatric rheumatology units in Israel. Participants received at least 2 vaccine doses. Safety analysis included adverse events and disease activity measures. Efficacy was assessed by COVID-19 infection rates. Immunogenicity was evaluated in a subset of participants using anti- receptor binding domain antibody titers. Thirty-one children with AIIRD and 45 immunocompetent controls with similar baseline characteristics were included. Safety profile was favorable, with mild or no adverse events reported. The adverse event rates were similar in the AIIRD and control groups after the first (27 (60 %) vs. 14 (45.2 %), p = 0.2977) and the second vaccine doses (22 (49.0 %) vs. 18 (58.1 %), p = 0.5799), respectively. AIIRD activity remained stable and low after vaccination. Breakthrough COVID-19 infection rates were similar between groups, with 15 (48.4 %) in the AIIRD vs. 25 (55.6 %) in the control group (p = 0.7029). All reported COVID-19 infections in the AIIRD group and 18 (72 %) in the control group were symptomatic (p = 0.033), although symptoms were generally mild, with no severe disease. The safety of the BNT162b2 COVID-19 vaccine was excellent in children ages 4-11 years with AIIRD and healthy controls. Efficacy between groups was similar.