Table 4. Association between number of flushing events per week and dengue outbreak occurrence over 20 lag weeks.
When five or more flushing events occurred in a week, compared with 0 flushing events, the risk of a dengue outbreak occurring in the subsequent weeks was significantly reduced up to six weeks after the flushing events occurred.
| Weeks after flushing events | 1 Day Flushed OR (95%CI) |
2 Day Flushed OR (95%CI) |
3 Day Flushed OR (95%CI) |
4 Day Flushed OR (95%CI) |
5 Day Flushed OR (95%CI) |
6 Day Flushed OR (95%CI) |
7 Day Flushed OR (95%CI) |
|---|---|---|---|---|---|---|---|
| 1 Week | 1.13 (0.88–1.44) | 1.16 (0.77–1.74) | 1.04 (0.67–1.62) | 0.84 (0.54–1.30) | 0.62 (0.38–1.02) | 0.44 (0.22–0.87) | 0.30 (0.11–0.79) |
| 2 Weeks | 1.13 (0.93–1.37) | 1.17 (0.85–1.60) | 1.07 (0.76–1.51) | 0.89 (0.64–1.25) | 0.69 (0.47–1.02) | 0.51 (0.29–0.88) | 0.37 (0.17–0.80) |
| 3 Weeks | 1.13 (0.97–1.30) | 1.18 (0.93–1.49) | 1.11 (0.86–1.43) | 0.95 (0.74–1.22) | 0.76 (0.57–1.03) | 0.59 (0.38–0.90) | 0.44 (0.24–0.82) |
| 4 Weeks | 1.13 (1.00–1.27) | 1.19 (0.98–1.44) | 1.14 (0.93–1.39) | 1.01 (0.83–1.22) | 0.84 (0.67–1.05) | 0.67 (0.48–0.94) | 0.53 (0.32–0.86) |
| 5 Weeks | 1.13 (1.01–1.26) | 1.20 (1.01–1.42) | 1.17 (0.97–1.40) | 1.06 (0.89–1.25) | 0.91 (0.75–1.10) | 0.76 (0.57–1.01) | 0.62 (0.40–0.94) |
| 6 Weeks | 1.13 (1.01–1.26) | 1.21 (1.01–1.44) | 1.19 (0.99–1.44) | 1.11 (0.93–1.31) | 0.98 (0.81–1.18) | 0.84 (0.64–1.10) | 0.70 (0.47–1.05) |
| 7 Weeks | 1.13 (1.00–1.27) | 1.22 (1.01–1.47) | 1.22 (1.00–1.49) | 1.15 (0.96–1.39) | 1.04 (0.86–1.27) | 0.91 (0.69–1.20) | 0.79 (0.53–1.19) |
| 8 Weeks | 1.13 (1.00–1.28) | 1.23 (1.00–1.50) | 1.24 (1.00–1.54) | 1.19 (0.98–1.46) | 1.10 (0.89–1.35) | 0.99 (0.74–1.31) | 0.87 (0.57–1.32) |
| 9 Weeks | 1.14 (1.00–1.29) | 1.24 (1.00–1.52) | 1.26 (1.01–1.58) | 1.23 (1.00–1.51) | 1.15 (0.93–1.43) | 1.05 (0.78–1.41) | 0.95 (0.62–1.45) |
| 10 Weeks | 1.14 (1.00–1.29) | 1.25 (1.01–1.53) | 1.29 (1.03–1.61) | 1.26 (1.02–1.56) | 1.20 (0.96–1.49) | 1.11 (0.82–1.49) | 1.01 (0.66–1.54) |
| 11 Weeks | 1.14 (1.01–1.29) | 1.26 (1.03–1.54) | 1.30 (1.05–1.63) | 1.29 (1.05–1.59) | 1.24 (1.00–1.53) | 1.16 (0.87–1.54) | 1.07 (0.71–1.61) |
| 12 Weeks | 1.15 (1.02–1.29) | 1.26 (1.04–1.54) | 1.32 (1.07–1.63) | 1.32 (1.08–1.61) | 1.27 (1.03–1.57) | 1.20 (0.91–1.58) | 1.11 (0.75–1.65) |
| 13 Weeks | 1.15 (1.03–1.29) | 1.27 (1.06–1.53) | 1.34 (1.09–1.64) | 1.34 (1.10–1.63) | 1.30 (1.06–1.59) | 1.23 (0.94–1.60) | 1.15 (0.80–1.66) |
| 14 Weeks | 1.15 (1.03–1.29) | 1.28 (1.07–1.54) | 1.35 (1.11–1.65) | 1.36 (1.12–1.65) | 1.32 (1.08–1.60) | 1.25 (0.98–1.61) | 1.17 (0.83–1.66) |
| 15 Weeks | 1.16 (1.04–1.30) | 1.29 (1.07–1.56) | 1.36 (1.11–1.68) | 1.37 (1.13–1.67) | 1.34 (1.10–1.63) | 1.27 (0.99–1.62) | 1.19 (0.85–1.66) |
| 16 Weeks | 1.16 (1.03–1.31) | 1.30 (1.07–1.59) | 1.38 (1.10–1.73) | 1.39 (1.12–1.72) | 1.35 (1.09–1.66) | 1.28 (1.00–1.64) | 1.20 (0.85–1.69) |
| 17 Weeks | 1.17 (1.02–1.34) | 1.31 (1.04–1.65) | 1.39 (1.07–1.80) | 1.40 (1.10–1.79) | 1.36 (1.08–1.71) | 1.29 (0.98–1.69) | 1.20 (0.83–1.74) |
| 18 Weeks | 1.17 (1.00–1.38) | 1.32 (1.01–1.73) | 1.40 (1.04–1.89) | 1.41 (1.06–1.87) | 1.36 (1.05–1.78) | 1.29 (0.94–1.75) | 1.20 (0.79–1.83) |
| 19 Weeks | 1.18 (0.98–1.43) | 1.33 (0.97–1.83) | 1.41 (0.99–2.01) | 1.42 (1.02–1.97) | 1.37 (1.01–1.86) | 1.29 (0.90–1.84) | 1.19 (0.73–1.96) |
| 20 Weeks | 1.19 (0.95–1.48) | 1.34 (0.93–1.94) | 1.42 (0.95–2.14) | 1.43 (0.97–2.09) | 1.37 (0.96–1.96) | 1.29 (0.85–1.95) | 1.19 (0.67–2.12) |
Bold values highlight statistically significant (p < 0.05) results
Abbreviations: OR, odds ratio; CI, confidence interval