Immunogenicity Analysis
EVENTS
The per-protocol immunogenicity set included participants without prior exposure to SARS-CoV-2 who had a baseline serum sample and at least 1 serum sample result available after the full primary vaccination series with no protocol violations or events considered likely to impact immune response at the study visit in question (eg, RT-PCR–positive swabs, SARS-CoV-2 seropositivity, or receipt of other COVID-19 vaccine outside the study). The primary assessment of effectiveness was based on a formal analysis of noninferiority of the neutralizing antibody response in a randomly selected subset of adolescents at day 35 compared with that in a similarly selected per-protocol immunogenicity subset of young adult participants aged 18 to 25 years in this study.For all assays, the geometric mean titers (GMTs) at each study visit (ie, at day 0 [baseline] and at day 35) and the geometric mean fold rise (GMFR) with 95% CI compared with baseline (day 0) were calculated by treatment group at each postvaccination study visit. The 95% CI was calculated based on the The study was powered for the demonstration of serologic effectiveness; further details are presented in the 