Table 3.
Description of all significant (p < 0.05) clusters (not shaded) and overlapping non-significant (n.s.) clusters with observed/expected > 1.2 (shaded) detected by the space-time permutation scan statistic in retrospective analysis.
| Credible event number |
Location of centroid |
Data stream |
Cluster duration | Number of zip codes |
Radius (km) |
Observed episodes (O) |
Expected episodes (E) |
O/E | p-value |
|---|---|---|---|---|---|---|---|---|---|
| Not credible | Bay Area | AC−F | 10/11 - 11/2 | 17 | 23 | 823 | 673 | 1.22 | 0.02 |
| Rx | 10/19 - 11/15 | 19 | 27 | 21 | 7 | 2.92 | n.s. | ||
| ED−F | 10/23 - 11/18 | 30 | 26 | 117 | 78 | 1.51 | n.s. | ||
| FluA | 10/31 - 11/12 | 8 | 11 | 2 | 0.06 | 31.12 | n.s. | ||
| 1 | Bay Area | AC+F | 12/7 - 1/3 | 58 | 57 | 710 | 557 | 1.27 | 0.0003 |
| Tests | 12/8 - 1/2 | 94 | 30 | 506 | 385 | 1.31 | 0.0003 | ||
| AC−F | 12/15 – 1/5 | 19 | 12 | 1,620 | 1,387 | 1.17 | 0.001 | ||
| ED+F | 12/11 - 12/25 | 10 | 9 | 13 | 3 | 4.79 | n.s. | ||
| ED−F | 12/16 - 12/26 | 69 | 24 | 313 | 248 | 1.26 | n.s. | ||
| FluA | 12/17 - 12/30 | 9 | 12 | 6 | 0.81 | 7.40 | n.s. | ||
| 2 | Fresno | Rx | 1/10 - 2/4 | 69 | 57 | 83 | 33 | 2.51 | 0.0001 |
| Tests | 1/14 - 2/8 | 85 | 86 | 634 | 403 | 1.57 | 0.0001 | ||
| AC+F | 1/14 - 2/10 | 87 | 68 | 505 | 365 | 1.38 | 0.0001 | ||
| AC−F | 1/15 - 2/10 | 70 | 48 | 3,111 | 2,585 | 1.20 | 0.0001 | ||
| ED+F | 1/16 - 2/9 | 31 | 12 | 70 | 35 | 1.98 | 0.04 | ||
| FluA | 1/18 - 2/8 | 77 | 101 | 238 | 148 | 1.61 | 0.0001 | ||
| ED−F | 1/15-2/10 | 69 | 53 | 243 | 172 | 1.41 | n.s. | ||
| 3 | Sacramento | AC+F | 1/30 - 2/22 | 105 | 133 | 1,078 | 859 | 1.25 | 0.0001 |
| AC−F | 2/2 - 2/29 | 144 | 84 | 17,079 | 15,824 | 1.08 | 0.0001 | ||
| Tests | 2/3 - 2/15 | 79 | 69 | 317 | 228 | 1.39 | 0.002 | ||
| ED−F | 2/6 - 3/4 | 87 | 51 | 1,491 | 1,256 | 1.19 | 0.0001 | ||
| ED+F | 2/11 - 2/23 | 63 | 22 | 211 | 145 | 1.46 | 0.03 | ||
| FluA | 2/12 -2/22 | 19 | 18 | 27 | 11 | 1.63 | n.s | ||
| Rx | 2/19 - 3/10 | 26 | 28 | 71 | 41 | 1.73 | n.s. | ||
| 4 | Bay Area | FluA | 3/1 - 3/28 | 168 | 61 | 193 | 131 | 1.48 | 0.003 |
| Tests | 3/7 - 4/3 | 111 | 35 | 721 | 570 | 1.27 | 0.0001 | ||
| AC−F | 3/17 - 4/13 | 129 | 39 | 11,036 | 10,239 | 1.08 | 0.0001 | ||
| ED−F | 3/4 - 3/9 | 35 | 5 | 64 | 41 | 1.58 | n.s. | ||
| ED+F | 3/17 - 3/18 | 5 | 2 | 6 | 0.7 | 9.24 | n.s. | ||
| Rx | 3/17 - 4/9 | 11 | 7 | 26 | 10 | 2.68 | n.s. | ||
| AC+F | 3/22 - 3/25 | 35 | 24 | 43 | 19 | 2.29 | n.s. | ||
| Not credible | Bay Area | ED−F | 4/17 - 5/14 | 42 | 35 | 413 | 294 | 1.40 | 0.0001 |
| Discharges | 5/1 - 5/15 | 20 | 16 | 39 | 15 | 2.69 | 0.01 | ||
| ED+F | 4/14 - 5/5 | 33 | 24 | 63 | 35 | 1.81 | n.s. | ||
| Admissions | 5/1 - 5/15 | 19 | 15 | 44 | 18 | 2.39 | n.s. |