Table 2. Multilevel negative binomial regression analysis to determine the association between daily incident cases and temperature.
| Mean Temperature (model 1) | |||||
| IRR (95%CI) Unadjusted | IRR (95%CI) Adjusted* | Coefficient | P value | Z | |
| Quartile 1 (-21º to 5.5º) | Reference | Reference | |||
| Quartile 2 (6 º to 10.5 º) | 1.16 (0.91 to 1.48) | 1.18 (0.92 to 1.52) | 0.17 | 0.188 | 1.32 |
| Quartile 3 (11 º to 18.5 º) | 1.01 (0.73 to 1.41) | 1.11 (0.78 to 1.59) | 0.10 | 0.550 | 0.60 |
| Quartile 4 (19 º to 36.5 º) | 0.82 (0.50 to 1.36) | 1.12 (0.67 to 1.88) | 0.11 | 0.663 | 0.44 |
| BCG vaccine | 0.35 (0.18 to 0.66) | 0.46 (0.25 to 0.87) | -0.76 | 0.016 | -2.41 |
| Minimum Temperature (model 2) | |||||
| IRR (95%CI) Unadjusted | IRR (95%CI) Adjusted* | Coefficient | P value | Z | |
| Quartile 1 (-26º to 1º) | Reference | Reference | |||
| Quartile 2 (2º to 6 º) | 0.71 (0.56 to 0.90) | 0.72 (0.57 to 0.93) | -0.32 | 0.011 | -2.56 |
| Quartile 3 (7 º to 13 º) | 0.69 (0.49 to 0.98) | 0.85 (0.59 to 1.24) | -0.15 | 0.405 | -0.83 |
| Quartile 4 (14 º to 34 º) | 0.55 (0.34 to 0.91) | 0.77 (0.46 to 1.29) | -0.25 | 0.329 | -0.98 |
| BCG vaccine | 0.35 (0.18 to 0.66) | 0.50 (0.27 to 0.94) | -0.69 | 0.032 | -2.15 |
| Maximum Temperature (model 3) | |||||
| IRR (95%CI) Unadjusted | IRR (95%CI) Adjusted* | Coefficient | P value | Z | |
| Quartile 1 (-16º to 9º) | Reference | Reference | |||
| Quartile 2 (10º to 16 º) | 1.25 (0.99 to 1.57) | 1.29 (1.02 to 1.63) | 0.25 | 0.034 | 2.12 |
| Quartile 3 (17 º to 25 º) | 1.25 (0.93 to 1.68) | 1.37 (0.99 to 1.87) | 0.31 | 0.051 | 1.95 |
| Quartile 4 (26 º to 44 º) | 0.89 (0.54 to 1.46) | 1.22 (0.73 to 2.04) | 0.19 | 0.448 | 0.76 |
| BCG vaccine | 0.35 (0.18 to 0.66) | 0.45 (0.24 to 0.84) | -0.79 | 0.013 | -2.50 |
Abbreviations: IRR- Incident Rate Ratio (Ratio between two incidence densities (rate in the exposed divided by rate in unexposed); CI- Confidence Interval; BCG- Bacillus Calmette–Guérin
*Adjusted or total number of tests done for COVID-19 in each country