Table 2.
Geometric Mean Antibody (Ab) Titers to Respiratory Syncytial Virus Subgroup A (RSV[A]) Small Hydrophobic Protein Ectodomain (SHe) Antigen Among Recipients of Alum- or DepoVax (DPX)–Adjuvanted RSV(A) SHe Vaccine
| Study Day, Group | Participants, No. | Ab Titer | GMTR (Specified Group: Placebo Group) | P a | ||||
|---|---|---|---|---|---|---|---|---|
| GM | Median (95% CI) | RSV(A)-Alum (10 µg) | DPX-RSV(A) (25 µg) | RSV(A)-Alum (25 µg) | Placebo | |||
| Day 7 | ||||||||
| DPX-RSV(A) (10 µg) | 8 | 50 | 50 (50–50) | 1.00 | .796 | .128 | 1 | 1 |
| RSV(A)-Alum (10 µg) | 8 | 54.53 | 50 (44.42–50) | 1.09 | .202 | .796 | .796 | |
| DPX-RSV(A) (25 µg) | 8 | 84.09 | 50 (24.6–66.92) | 1.68 | .128 | .128 | ||
| RSV(A)-Alum (25 µg) | 8 | 50 | 50 (50–287.48) | 1.00 | 1 | |||
| Placebo | 8 | 50 | 50 (50–50) | NA | ||||
| Day 28 | ||||||||
| DPX-RSV(A) (10 µg) | 8 | 100 | 50 (19.42–515.02) | 1.30 | .411 | .556 | .637 | .723 |
| RSV(A)-Alum (10 µg) | 8 | 54.53 | 50 (44.42–66.92) | 0.71 | .162 | .723 | .637 | |
| DPX-RSV(A) (25 µg) | 8 | 154.22 | 50 (25.38–937.16) | 2.00 | .292 | .348 | ||
| RSV(A)-Alum (25 µg) | 8 | 70.71 | 50 (38.06–131.38) | 0.92 | .906 | |||
| Placebo | 8 | 77.11 | 50 (27.68–214.78) | NA | ||||
| Day 56b | ||||||||
| DPX-RSV(A) (10 µg) | 8 | 518.74 | 282.84 (49.09–5481.28) | 10.37 | .107 | 1 | .076 | .025 |
| RSV(A)-Alum (10 µg) | 8 | 100 | 50 (24.18–413.48) | 2.00 | .107 | .863 | .491 | |
| DPX-RSV(A) (25 µg) | 8 | 518.74 | 200 (58.12–4629.83) | 10.37 | .076 | .025 | ||
| RSV(A)-Alum (25 µg) | 8 | 84.09 | 50 (24.6–287.48) | 1.68 | .605 | |||
| Placebo | 8 | 50 | 50 (50–50) | NA | ||||
| Day 63 | ||||||||
| DPX-RSV(A) (10 µg) | 8 | 951.37 | 1131.37 (102.48–8832.1) | 7.07 | .058 | .866 | .019 | .072 |
| RSV(A)-Alum (10 µg) | 8 | 129.68 | 50 (33.69–499.22) | 0.96 | .083 | .613 | .972 | |
| DPX-RSV(A) (25 µg) | 8 | 800 | 565.69 (97.89–6538.25) | 5.94 | .028 | .1 | ||
| RSV(A)-Alum (25 µg) | 8 | 77.11 | 50 (27.68–214.78) | 0.57 | .6 | |||
| Placebo | 7 | 134.59 | 50 (26.98–671.45) | NA | ||||
| Day 84 | ||||||||
| DPX-RSV(A) (10 µg) | 8 | 2467.54 | 4525.48 (248.42–24 509.7) | 49.35 | <.001 | .086 | <.001 | <.001 |
| RSV(A)-Alum (10 µg)c | 8 | 91.7 | 50 (27.15–309.68) | 1.83 | <.001 | .922 | .497 | |
| DPX-RSV(A) (25 µg) | 8 | 11 737.7 | 12 800 (2317.1–59 459) | 234.75 | <.001 | <.001 | ||
| RSV(A)-Alum (25 µg)c | 8 | 84.09 | 50 (24.6–287.48) | 1.68 | .56 | |||
| Placebo | 8 | 50 | 50 (50–50) | NA | ||||
| Day 236 | ||||||||
| DPX-RSV(A) (10 µg) | 8 | 5381.74 | 6400 (866.82–33 413.1) | 98.69 | <.001 | 1 | <.001 | <.001 |
| RSV(A)-Alum (10 µg)c | 8 | 50 | 50 (50–50) | 0.92 | <.001 | .748 | .915 | |
| DPX-RSV(A) (25 µg) | 8 | 5381.74 | 6400 (543.94–53 246.8) | 98.69 | <.001 | <.001 | ||
| RSV(A)-Alum (25 µg)c | 8 | 64.84 | 50 (35.07–119.89) | 1.19 | .83 | |||
| Placebo | 8 | 54.53 | 50 (44.42–66.92) | NA | ||||
See “Methods” for a description of vaccine formulations. Recipients received 2 doses of vaccine or placebo (one on day 0 and another on day 56).
Abbreviations: CI, confidence interval; GM, geometric mean; GMTR, geometric mean titer ratio; NA, not applicable.
aValues <.05 are statistically significant.
bSerum specimens were procured on day 56, before the second dose of vaccine was given.
cNote that participants in the RSV(A)-Alum group received placebo, rather than RSV(A)-Alum, on day 56.