Safety and immunogenicity of the BBIBP-CorV vaccine in adolescents aged 12-17 years in Thai population, prospective cohort study.

Introduction: COVID-19 pandemic affects all populations worldwide, including adolescents. Adolescents can develop a severe form of COVID-19, especially with comorbidity underlying. The prior studies of the mRNA COVID-19 vaccine showed excellent effectiveness in adolescents. Therefore, this study aimed to evaluate the safety and effectiveness of the BBIBP-CorV vaccine with the immunobridging approach in Thai adolescents. Methods: This single-center, prospective cohort study compared the immunogenicity after 2 doses of the BBIBO-CorV vaccine with 21 days interval of participants aged 12-17 years with 18-30 years at Chulabhorn Hospital, Chulabhorn Royal Academy, Bangkok, Thailand. The key eligible criteria were healthy or had stable pre-existing comorbidity participants, aged 12-17 years. The primary endpoint was the anti-receptor binding domain antibody concentration at 4 weeks after dose 2 of the vaccine. In addition, safety profiles were solicited adverse events within 7 days after each dose of vaccine and any adverse events through 1 month after dose 2 of the vaccine. Results: Four weeks after the second vaccination, the GMC of anti-RBD antibody in the adolescent cohort was 102.9 BAU/mL (95%CI; 91.0-116.4) and 36.9 BAU/mL (95%CI; 30.9-44.0) in the adult cohort. The GMR of the adolescent cohort was 2.79 (95%CI; 2.25-3.46, p-value; <0.0001) compared with the adult cohort which met non-inferiority criteria. The reactogenicity was slightly less reported in the adolescent cohort compared with the adult cohort. No serious adverse events were reported in both cohorts. Conclusion: Vaccination with the BBIBP-CorV vaccine in the adolescent participants was safe and effective.