Table 2.
Respiratory Syncytial Virus Subtype A (RSV-A) Neutralizing Antibody Titers—RSV F-020, According-to-Protocol Cohort for Immunogenicity
| Group,a Timing | Evaluated, No. | Titer, No. (%) | Vaccine Responseb | ||
|---|---|---|---|---|---|
| ≥512 | ≥1024 | Evaluated, No. | Response, No. (%) | ||
| 30RSV-PreF | |||||
| Before vaccination | 117 | 43 (36.8) | 18 (15.4) | … | … |
| After vaccination | |||||
| Day 30 | 117 | 107 (91.5) | 74 (63.2) | 117 | 81 (69.2) |
| Day 60 | 109 | 89 (81.7) | 49 (45.0) | 108 | 52 (48.1) |
| Day 90 | 112 | 83 (74.1) | 43 (38.4) | 111 | 42 (37.8) |
| 60RSV-PreF | |||||
| Before vaccination | 117 | 40 (34.2) | 12 (10.3) | … | … |
| After vaccination | |||||
| Day 30 | 117 | 110 (94.0) | 72 (61.5) | 117 | 83 (70.9) |
| Day 60 | 111 | 90 (81.1) | 42 (37.8) | 111 | 59 (53.2) |
| Day 90 | 111 | 78 (70.3) | 38 (34.2) | 111 | 42 (37.8) |
| 60RSV-PreF-Al | |||||
| Before vaccination | 118 | 50 (42.4) | 26 (22.0) | … | … |
| After vaccination | |||||
| Day 30 | 118 | 111 (94.1) | 84 (71.2) | 118 | 91 (77.1) |
| Day 60 | 108 | 93 (86.1) | 57 (52.8) | 108 | 56 (51.9) |
| Day 90 | 110 | 86 (78.2) | 48 (43.6) | 110 | 49 (44.5) |
| Tdap | |||||
| Before vaccination | 118 | 45 (38.1) | 20 (16.9) | … | … |
| After vaccination | |||||
| Day 30 | 118 | 42 (35.6) | 17 (14.4) | 118 | 6 (5.1) |
| Day 60 | 111 | 39 (35.1) | 14 (12.6) | 109 | 5 (4.6) |
| Day 90 | 111 | 45 (40.5) | 14 (12.6) | 109 | 4 (3.7) |
aThe 30RSV-PreF group received nonadjuvanted RSV vaccine containing 30 µg of RSV–prefusion F protein (PreF), the 60RSV-PreF group received nonadjuvanted RSV vaccine containing 60 µg of RSV PreF, the 60RSV-PreF-Al group received aluminum-adjuvanted RSV vaccine containing 60 µg of RSV PreF, and the Tdap group received an adult formulation of combined tetanus toxoid-diphtheria toxoid-acellular pertussis vaccine.
bVaccine response rates involving neutralizing antibodies were calculated as follows: at least a 4-fold increase from the prevaccination level if the prevaccination neutralizing antibody titer was <128, at least a 3-fold increase from the prevaccination level if the prevaccination neutralizing antibody titer was [128–256], at least a 2.5-fold increase from the prevaccination level if the prevaccination neutralizing antibody titer was [256–1024], and at least a 1-fold increase from the prevaccination level if the prevaccination neutralizing antibody titer was >1024.