Table 2. Immune response among different batches of EV71 vaccine or placebo in subjects who were seronegative at baseline on day 56, by treatment and age groups.
| Assessment variables | Vaccine | Placebo | P value# | ||||
|---|---|---|---|---|---|---|---|
| Pooled batches | Batch 1 | Batch 2 | Batch 3 | P value* | |||
| 6–11 mo | n = 998 | n = 343 | n = 330 | n = 325 | n = 997 | ||
| GMT (U/mL) | 439.1 (402.1–479.5) | 420.1 (359.8–490.5) | 413.1 (353.7–482.4) | 489.6 (422.3–567.6) | 0.24 | 3.6 (3.3–3.9) | <0.001 |
| Proportion with NTAb titer ≥ 8U/mL | 983, 98.5 (97.5–99.2) | 337, 98.3 (96.0–99.4) | 325, 98.5 (96.3–99.6) | 321, 98.8 (96.7–99.7) | 0.86 | 189, 19.0 (16.6–21.6) | <0.001 |
| Proportion with NTAb titer ≥ 32U/mL | 957, 95.9 (94.4–97.0) | 326, 95.0 (92.0–97.1) | 315, 95.5 (92.5–97.4) | 316, 97.2 (94.6–98.7) | 0.32 | 57, 5.7 (4.4–7.4) | <0.001 |
| 12–35 mo | n = 2432 | n = 796 | n = 823 | n = 813 | n = 2444 | ||
| GMT (U/mL) | 473.0 (447.3–500.2) | 401.5 (362.0–445.4) | 492.2 (448.6–540.1) | 533.6 (486.0–585.8) | <0.001 | 4.1 (3.8–4.4) | <0.001 |
| Proportion with NTAb titer ≥ 8U/mL | 2404, 98.9 (98.3–99.2) | 783, 98.4 (97.2–99.1) | 818, 99.4 (98.5–99.8) | 803, 98.8 (97.7–99.4) | 0.15 | 504, 20.6 (19.0–22.3) | <0.001 |
| Proportion with NTAb titer ≥ 32U/mL | 2342, 96.3 (95.5–97.0) | 761, 95.6 (93.9–96.9) | 794, 96.5 (94.9–97.6) | 787, 96.8 (95.3–97.9) | 0.42 | 209, 8.6 (7.5–9.8) | <0.001 |
| Total | n = 3430 | n = 1139 | n = 1153 | n = 1138 | n = 3441 | ||
| GMT (U/mL) | 462.9 (441.6–485.3) | 407.0 (373.5–443.6) | 468.1 (432.2–507.0) | 520.6 (481.2–563.3) | <0.001 | 4.0 (3.7–4.2) | <0.001 |
| Proportion with NTAb titer ≥ 8U/mL | 3387, 98.8 (98.3–99.1) | 1120, 98.3 (97.4–99.0) | 1143, 99.1 (98.4–99.6) | 1124, 98.8 (97.9–99.3) | 0.23 | 693, 20.1 (18.8–21.5) | <0.001 |
| Proportion with NTAb titer ≥ 32U/mL | 3299, 96.2 (95.5–96.8) | 1087, 95.4 (94.0–96.6) | 1109, 96.2 (94.9–97.2) | 1103, 96.9 (95.7–97.8) | 0.18 | 266, 7.7 (6.9–8.7) | <0.001 |
Data are GMT (95% CI) or n, % (95% CI). GMT, geometric mean titer; n, number of subjects. *The P values were calculated for the comparison among the 3 batches of EV71 vaccines. #The P values were calculated for the comparison between the pooled EV71 vaccine group and the placebo group.