Table 2 Comparison of epidemiological characteristics between before (2008–2015) and after (2017–2019) introduction of EV71 vaccines in Yunnan Province
Items | Pre-vaccine introduction (2008–2015) n = 400,704 | Post-vaccine introduction (2017–2019) n = 277,731 | X2 test P value |
|---|---|---|---|
Sex | < 0.01 | ||
Female | 164,082 (40.95) | 116,755 (42.04) | |
Male | 236,622 (59.05) | 160,976 (57.96) | |
Age | < 0.01 | ||
0–0.5 | 4647 (1.16) | 2909 (1.05) | |
0.6–2.9 | 229,931 (57.38) | 157,810 (56.82) | |
3–6.9 | 149,927 (37.42) | 104,597 (37.66) | |
7–14.9 | 15,049 (3.76) | 11,223 (4.04) | |
≥ 15 | 1150 (0.29) | 1192 (0.43) | |
Median (IQR) | 2.5 (1.6,3.7) | 2.5 (1.6, 4.0) | < 0.01a |
Area | < 0.01 | ||
Central | 187,087 (46.70) | 104,454 (37.61) | |
Northeastern | 33,648 (8.40) | 33,311 (11.99) | |
Northwestern | 82,590 (20.60) | 62,432 (22.48) | |
Southern | 97,379 (24.30) | 77,534 (27.92) | |
Case classification | < 0.01 | ||
Mild | 393,261 (98.14) | 275,995 (99.37) | |
Severe | 7316 (1.83) | 1724 (0.62) | |
Death | 127 (0.03) | 12 (0.01) | |
Pathogen | < 0.01 | ||
EV71 | 14,208 (44.1) | 3239 (14.41) | |
CV-A16 | 12,987 (40.3) | 6307 (28.06) | |
Others | 5052 (15.7) | 12,929 (57.53) |