Table 2.
Timing of Specimen Collection, Plus Results from Laboratory Assays to Identify Illness Etiology as Influenza, by Intervention Group, for Laboratory-Confirmed Symptomatic Influenzatype A (H3N2) and Type B
| Group, characteristic | No. (%) of subjects |
|||
| LAIV arm | TIV arm | Placebo arm | Total | |
| Subjects with laboratory-confirmed symptomatic influenza A (H3N2) | ||||
| No. of subjects | 80 | 42 | 44 | 166 |
| Time from illness onset to specimen collectiona | ||||
| 0-2 days | 57 (71.3) | 23 (54.8) | 27 (62.8) | 107 (64.8) |
| >2 days | 23 (28.8) | 19 (45.2) | 16 (37.2) | 58 (35.2) |
| Isolation in cell culture | 46 (57.5)b | 31 (73.8) | 37 (84.1) | 114 (68.7) |
| rtPCR Ct values | ||||
| <25 | 17 (21.3)b | 13 (31.0) | 18 (40.9) | 48 (28.9) |
| 25–30 | 26 (32.5) | 10 (23.8) | 16 (36.4) | 52 (31.3) |
| >30 - <40 | 37 (46.3) | 19 (45.2) | 10 (22.7) | 66 (39.8) |
| Subjects with laboratory-confirmed symptomatic influenza B | ||||
| No. of subjects | 9 | 9 | 11 | 29 |
| Time from illness onset to specimen collection | ||||
| 0-2 days | 9 (100)b | 5 (55.6) | 4 (36.4) | 18 (62.1) |
| >2 days | 0 (0) | 4 (44.4) | 7 (63.6) | 11 (37.9) |
| Isolation in cell culture | 9 (100) | 9 (100) | 10 (90.9) | 28 (96.6) |
| rtPCR Ct values | ||||
| <25 | 1 (11.1) | 2 (22.2) | 3 (27.3) | 6 (20.7) |
| 25–30 | 2 (22.2) | 3 (33.3) | 3 (27.3) | 8 (27.6) |
| >30 to <40 | 6 (66.7) | 4 (44.4) | 5 (45.5) | 15 (51.7) |
NOTE. Ct, cycle threshold; LAIV, live attenuated vaccine; rtPCT, real-time polymerase chain reaction; TIV, trivalent inactivated vaccine.
a
Numbers do not add to expected totals due to missing data
b
For LAIV vs placebo arm, P < .05 (by χ2 test, with adjustment for timing of specimen collection).