Table 3. Multilevel negative binomial regression analysis to determine the association between daily mortality counts and temperature.

Mean Temperature (model 4)
Temperature quartile	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)	1.18 (0.87 to 1.59)	1.15 (0.84 to 1.58)	0.14	0.373	0.89
Quartile 3 (11 º to 18.5 º)	0.97 (0.65 to 1.45)	1.12 (0.71 to 1.77)	0.11	0.612	0.51
Quartile 4 (19 º to 36.5 º)	0.87 (0.47 to 1.62)	1.99 (0.61 to 2.34)	0.18	0.594	0.53
BCG vaccine	0.37 (0.17 to 0.79)	0.43 (0.19 to 1.00)	-0.83	0.050	-1.96
Minimum Temperature (model 5)
Temperature quartile	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)	0.62 (0.46 to 0.84)	0.62 (0.45 to 0.85)	-0.47	0.003	-2.95
Quartile 3 (7 º to 13 º)	0.66 (0.43 to 1.00)	0.75 (0.47 to 1.21)	-0.27	0.248	-1.15
Quartile 4 (14 º to 34 º)	0.75 (0.40 to 1.37)	0.96 (0.50 to 1.86)	-0.035	0.916	-0.11
BCG vaccine	0.37 (0.17 to 0.79)	0.47 (0.20 to 1.09)	-0.76	0.078	-1.77
Maximum Temperature (model 6)
Temperature quartile	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)	1.34(1.01 to 1.76)	1.37 (1.02 to 1.83)	0.31	0.038	2.08
Quartile 3 (17 º to 25 º)	1.24(0.86 to 1.79)	1.40 (0.94 to 2.10)	0.34	0.095	1.67
Quartile 4 (26 º to 44 º)	1.11 (0.60 to 2.06)	1.46 (0.75 to 2.84)	0.38	0.259	1.13
BCG vaccine	0.37 (0.17 to 0.79)	0.42 (0.18 to 0.95)	-0.87	0.037	-2.09

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