Table 1. Age–sex distribution for the influenza A (H1N1) cases in the early stage of the epidemic in mainland China.
| Gender-Age | Total cases (n = 420) | Imported cases (n = 297) | Second-generation cases (n = 85) | P |
| Gender | ||||
| Male/Female(cases) | 187/169 (45/40) | 161/136 (54/46) | 34/46 (43/57) | 0.06 |
| Age(year) | 22±15(0.5–73) | 23±15 (0.5–73) | 19±14 (1.5–59) | |
| Age distribution | ||||
| 0∼ | 16 (3.8) | 13 (4.4) | 3 (3.5) | |
| 6∼ | 116 (27.6) | 83 (27.9) | 33 (38.8) | |
| 15∼ | 113 (26.9) | 96 (32.3) | 17 (20.0) | |
| 25∼ | 40 (9.5) | 29 (9.8) | 10 (11.8) | |
| 35∼ | 26 (6.2) | 21 (7.1) | 5 (5.9) | |
| 45∼ | 31 (7.4) | 27 (9.1) | 4 (4.7) | |
| 55∼ | 10 (2.4) | 8 (2.7) | 2 (2.4) | |
| 65∼ | 4 (1.0) | 4 (1.3) | – | |
| Unknown | 64 (15.2) | 16 (5.4) | 9 (10.6) |
Note: Comparison between imported and second-generation cases, P = 0.06.