Immunogenicity and safety of BNT162b2 vaccine in patients with juvenile immune mediated inflammatory disease

BACKGROUND: COVID-19 vaccines have significantly reduced mortality and are safe for healthy children; however, research in pediatric populations with juvenile immune-mediated inflammatory diseases (IMIDs) is limited. METHODS: The Brazilian multicenter longitudinal SAFER-Study evaluates immunogenicity and safety of the BNT162b2/Pfizer vaccine in IMID patients. The juvenile cohort enrolled patients aged 12-17 years between August and December 2021 and compared them with adults under 40 years from the adult cohort. Safety was assessed by monitoring post-vaccination adverse events (AEs), immunogenicity was measured by IgG antibodies against the SARS-CoV-2 spike receptor-binding domain and seroconversion rates. RESULTS: A total of 123 participants were included: 86 adolescents and 37 adult controls. In adolescents, local AEs were most frequent; no serious or life-threatening AEs occurred. Significant increases in IgG-S levels were observed after the two doses in both cohorts (p < 0.001). Seroconversion after the second dose reached 97% overall and 100% after the third dose. In juvenile SLE and JIA patients, vaccination did not significantly affect disease activity. CONCLUSION: The BNT162b2 vaccine was safe and immunogenic in adolescents with IMIDs, including those with high immunosuppression and comorbidities, showing similar responses to adults. These findings support vaccination in this vulnerable population and contribute to evidence-based recommendations. IMPACT: BNT162b2 COVID-19 vaccine demonstrated a favorable safety profile and immunogenicity in adolescents with juvenile immune-mediated inflammatory diseases (IMID), with responses comparable to those observed in adults. Real life data on this population remain limited, and further evidence regarding vaccine safety and immunogenicity is needed. This study represents the first multicenter, longitudinal registry of Brazilian adolescents with IMID receiving BNT162b2. Comprehensive data on the safety and immunogenicity of BNT162b2 in highly immunosuppressed adolescents with IMID and comorbidities are crucial to guide clinical decision-making, mitigate vaccine hesitancy, and enhance vaccination coverage within this vulnerable population.