Adverse Events Following COVID-19 Vaccination in Adolescents: Insights From Pharmacovigilance Study of VigiBase

Abstract

Background: During coronavirus disease 2019 (COVID-19) pandemic, several COVID-19 vaccines were licensed with fast-track procedures. Although these vaccines have demonstrated high immunogenicity, there has been concerns on the serious adverse events (AEs) following COVID-19 vaccination among adolescents. We aimed to analyze comparative safety of COVID-19 vaccination in adolescents.

Methods: In this pharmacovigilance study, we performed a disproportionality analysis using VigiBase, the World Health Organization's global individual case safety report (ICSR) database. To compare serious AEs reported following COVID-19 vaccines vs. all other vaccines in adolescents aged 12-17 years, ICSRs following any vaccines on adolescents aged 12-17 years were included, defining cases as reports with the AEs of interest, with all other AEs as non-cases. The AEs of interest were myocarditis/pericarditis, multisystem inflammatory syndrome/Kawasaki disease (MIS/KD), anaphylaxis, Guillain-Barré syndrome (GBS), and immune thrombocytopenia (ITP). We conducted a disproportionality analysis to estimate reporting odds ratio (ROR) with 95% confidence interval (CI) for each AE of interest, adjusted for sex by using logistic regression.

Results: Of 99,735 AE reports after vaccination in adolescents, 80,018 reports were from COVID-19 vaccinated adolescents (52.9% females; 56.3% America). The AEs of interest were predominantly reported as serious AE (76.1%) with mRNA vaccines (99.4%). Generally, higher reporting odds for the AEs were identified following COVID-19 vaccination in adolescents; myocarditis/pericarditis (2,829 reports for the COVID-19 vaccine vs. 35 for all other vaccines, adjusted ROR [aROR], 19.61; 95% CI, 14.05-27.39), and MIS/KD (104 vs. 6, aROR, 4.33; 95% CI, 1.89-9.88). The reporting odds for anaphylaxis (515 vs. 165, aROR, 0.86; 95% CI, 0.72-1.02), GBS (94 vs. 40, aROR, 0.64; 95% CI, 0.44-0.92) and ITP (52 vs. 12, aROR, 1.12; 95% CI, 0.59-2.09) were not significantly higher following COVID-19 vaccination.

Conclusion: In this study, there were disproportionate reporting of immune-related AEs following COVID-19 vaccination. While awaiting definitive evidence, there is a need to closely monitor for any signs of immune-related AEs following COVID-19 vaccination among adolescents.

Keywords: Adolescents; Adverse Events; COVID-19 Vaccine; Disproportionality Analysis.