Signals of disproportionate reporting of events supposedly attributable to COVID-19 vaccines in children and adolescents: case-non-case study, Brazil, 2022

OBJECTIVES: To trace and describe signals of disproportionate reporting for COVID-19 vaccines in children and adolescents in Brazil, based on the analysis of reports of events supposedly attributable to vaccination or immunization (ESAVI), comparing the signals detected with events described in the package inserts. METHODS: Case-non-case study based on the ESAVI reported in the e-SUS Notifica system in 2022, calculated by the reporting odds ratio (ROR) and information component (IC). Signal definition criteria were greater than or equal to three notifications, ROR greater than one, or credibility interval (CI) 025 greater than zero. RESULTS: In 2022, there were 225,693 reports, of which 26,128 were vaccine-event pairs in children and adolescents, mostly non-serious events (84.6%). We traced 39 signals of disproportionate reporting for the Sinovac vaccine and 53 signals for the Pfizer-BioNTech vaccine, including signals not described in the package insert. For Sinovac, the terms not described in the package insert were: dysarthria (ROR 23.44; IC 1.73), epistaxis (ROR 5.22; IC 1.49), ocular pruritus (ROR 4.33; IC 1.19) and muscle weakness (ROR 3.75; IC 1.19). For Pfizer-BioNTech, lymph node pain (ROR 26.74; IC 1.49), epistaxis (ROR 9.65; IC 1.76), 1st degree atrioventricular block (ROR 9.36; IC 1.44), hypersomnia (ROR 7.49; IC 1.36) and chest pain (ROR 6.03; IC 1.63). CONCLUSION: The analysis traced signals of disproportionate reporting of ESAVI in children and adolescents, including events not described in the package insert, which should be considered hypothesis generators. We note the need for further epidemiological studies to investigate the findings.