Areas (altitude) | Subjects | With symptoms | Without symptoms (cases) | Incidence (%) |
Kunming (1891 m) | 105 | 64 | 41 | 60.95 |
Zhengzhou (111 m) | 102 | 84 | 18 | 82.35 |
Beijing (31 m) | 86 | 72 | 14 | 83.72 |
Total | 293 | 220 | 83 | 75.09 |