Table 2. SARS-CoV-2 Serum Neutralization Assay Results 1 Month after Dose 2 of BNT162b2 among Participants without Evidence of Infection.*.
| Age Group | No. of Participants | Geometric Mean 50% Neutralizing Titer (95% CI)† | Geometric Mean Ratio (95% CI), 12 to 15 Yr vs. 16 to 25 Yr‡ |
|---|---|---|---|
| 12–15 yr | 190 | 1239.5 (1095.5–1402.5) | 1.76 (1.47–2.10) |
| 16–25 yr | 170 | 705.1 (621.4–800.2) | — |
Results are for the subset of participants in the dose 2 immunogenicity population that could be evaluated (i.e., participants who underwent randomization and received two BNT162b2 doses in accordance with the protocol, received dose 2 within the prespecified window, had at least one valid and determinate immunogenicity result from a blood sample obtained within 28 to 42 days after dose 2, and had no major protocol deviations) who had no evidence of previous SARS-CoV-2 infection. Participants without evidence of previous infection were those who had no serologic or virologic evidence (up to 1 month after receipt of the last dose) of past SARS-CoV-2 infection (i.e., N-binding antibody [serum] negative at vaccination visit 1 and SARS-CoV-2 not detected by NAAT [nasal swab] at vaccination visits 1 and 2) and had negative NAAT results (nasal swab) at any unscheduled visit up to 1 month after dose 2.
Geometric mean titers and two-sided 95% confidence intervals were calculated by exponentiating the mean logarithm of the titers and the corresponding confidence intervals (based on the Student’s t distribution). Assay results below the lower limit of quantitation were set to 0.5 times the lower limit of quantitation.
The geometric mean ratio and two-sided 95% confidence intervals were calculated by exponentiating the mean difference of the logarithms of the titers (the 12-to-15-year-old cohort minus the 16-to-25-year-old cohort) and the corresponding confidence intervals (based on the Student’s t distribution). The noninferiority criterion was met, since the lower boundary of the two-sided confidence interval for the geometric mean ratio was greater than 0.67.