Study endpoints
The primary endpoint of the study included the long-term safety of the BNT162b2 mRNA vaccine, as evaluated by side-effects following the second and third doses in adolescents with AIIRDs compared with healthy controls, and the impact of vaccination on clinical disease activity in the patient group. The secondary endpoints were long-term immunogenicity of the BNT162b2 mRNA vaccine in adolescents with AIIRDs measured at 2–8 weeks and 6 months after the second vaccine and at 2–8 weeks after the third vaccine dose, compared with controls. Breakthrough COVID-19 infections were recorded based on positive SARS-CoV-2 polymerase chain reaction (PCR) tests, documented ≥14 days following vaccination.