Table 2.
Summary of Outcomes of Yellow Fever Neutralizing Antibody Titers in 2 Infant Studies, at 28 Days After Vaccination
| Age | Study ID | Vaccine Group | No. Testeda/Vaccinated With Yellow Fever Vaccine | Yellow Fever NT Titer ≥1:8, % (95% CI) | Yellow Fever NT ≥2-Fold Rise, % (95% CI) | Yellow Fever NT, Geometric Mean Titer (95% CI) |
|---|---|---|---|---|---|---|
| 9 mo | Study Ab: PsA-TT-004 |
Group 1A PsA-TT 10 µg (dose 2) |
174/193 | 79.3 (72.5–85.1) | 68.4 (60.9–75.2) | 16.6 (13.9–19.9) |
| Group 1B PsA-TT 5 µg (dose 2) |
162/191 | 74.7 (67.3–81.2) | 71.0 (63.3–77.8) | 15.0 (12.4–18.2) | ||
| Group 1C PsA-TT 2.5 µg (dose 2) |
177/194 | 67.8 (60.4–74.6) | 64.8 (57.2–71.8) | 12.1 (10.1–14.5) | ||
| Group 2 PsA-TT 10 µg (dose 1) |
160/189 | 70.0 (62.3–77.0) | 67.1 (59.2–74.3) | 12.6 (10.5–15.1) | ||
| Group 3 Control |
… | … | ||||
| Group 4 Control |
168/190 | 71.4 (64.0–78.1) | 67.1 (59.4–74.1) | 15.2 (12.5–18.6) | ||
| Study Bc: PsA-TT-007 |
Group 1A PsA-TT 10 µg (dose 1) |
60/300 | 98.3 (91.1–100) | 98.3 (91.1–100) | 33.9 (28.9–39.7) | |
| Group 1B PsA-TT 5 µg (dose 1) |
60/300 | 96.7 (88.5–99.6) | 91.7 (81.6–97.2) | 33.3 (27.5–40.3) | ||
| Group 2A PsA-TT 10 µg (dose 1) |
61/300 | 95.1 (86.3–99.0) | 93.4 (84.1–98.2) | 32.5 (26.8–39.4) | ||
| Group 2B PsA-TT 5 µg (dose 1) |
59/300 | 96.6 (88.3–99.6) | 89.8 (79.2–96.2) | 31.6 (25.8–38.7) | ||
| Group 3 Control |
60/300 | 96.7 (88.5–99.6) | 90.0 (79.5–96.2) | 29.1 (24.6–34.6) |
Abbreviations: CI, confidence interval; NT, neutralization titers; PsA-TT, group A meningococcal conjugate vaccine.
a No. of subjects tested at 28 days after vaccination.
b Study A: The difference in ≥1:8 percentage was −7.9% (95% CI, −17.0 to 1.3) between group 4 and group 1A, −3.3% (95% CI, −12.8 to 6.4) between group 4 and group 1B, 3.6% (95% CI, −6.1 to 13.3) between group 4 and group 1C, and 1.4% (95% CI, −8.4 to 11.3) between group 4 and group 2; the difference in ≥2-fold rise percentage was −1.3% (95% CI, −11.2 to 8.6) between group 4 and group 1A, −3.9% (95% CI, −13.9 to 6.1) between group 4 and group 1B, 2.3% (95% CI, −7.8 to 12.3) between group 4 and group 1C, and −0.0% (95% CI, −10.2 to 10.2) between group 4 and group 2, 4 weeks after vaccination by Miettinen–Nurminen method. For the comparison of NT geometric mean titers (GMTs) between groups, the P value was >.05 (all groups) by analysis of variance (ANOVA) after adjusting for age, sex, and baseline titer.
c Study B: The difference in ≥1:8 percentage was −1.7% (95% CI, −10.0 to 5.9) between group 3 and group 1A, 0.0% (95% CI, −8.5 to 8.5) between group 3 and group 1B, 1.6% (95% CI, −7.1 to 10.7) between group 3 and group 2A, and 0.1% (95% CI, −8.5 to 8.7) between group 3 and group 2B; The difference in ≥2-fold rise percentage was −8.3% (95% CI, −18.8 to .1) between group 3 and group 1A, −1.7% (95% CI, −13.1 to 9.6) between group 3 and group 1B, −3.4% (95% CI, −14.6 to 7.2) between group 3 and group 2A, and 0.2% (95% CI, −11.5 to 12.0) between group 3 and group 2B, 4 weeks after vaccination by Miettinen–Nurminen method. For the comparison of NT GMTs between groups, the P value was >.05 (all groups) by ANOVA after adjusting for age, sex, and baseline titer.