Factors influencing SARS-CoV-2 weekly growth rates and positivity-corrected growth-rates, across Canada, Mar. 15, 2020, to Mar. 6, 2021
| Variable | National level* n = 51 | Provincial level* n = 279 | ||
|---|---|---|---|---|
| Unadjusted† | Adjusted‡ | Unadjusted† | Adjusted‡ | |
| Weekly growth rate | ||||
| Coeffiicients, GRR (95% CI) | ||||
| Mean out-of-home mobility in previous 3-week period, per 10% increase | 1.19 (1.13–1.24) | 1.25 (1.20–1.29) | 1.16 (1.12–1.20) | 1.20 (1.16–1.24) |
| Temperature, per 5°C increase | 0.83 (0.75–0.93) | 0.88 (0.86–0.91) | ||
| Model characteristics | ||||
| Residual autocorrelation | 0.14 | 0.15 | 0.20 | 0.09 |
| Model complexity (degrees of freedom) | 7.8 | 7.5 | 23.9 | 15.6 |
| Goodness-of-fit, R2 (%) | 81.8 | 81.6 | 33.3 | 38.2 |
| Model fit criterion (AIC) | −28.8 | −28.9 | 242.1 | 204.1 |
| Positivity-corrected weekly growth rate | ||||
| Coeffiicients, GRR (95% CI) | ||||
| Mean out-of-home mobility in previous 3-week period, per 10% increase | 1.27 (1.10–1.47) | 1.35 (1.17–1.55) | 1.13 (1.08–1.19) | 1.29 (1.21–1.38) |
| Temperature, per 5°C increase | 0.73 (0.56–0.94) | 0.89 (0.84–0.94) | ||
| Model characteristics | ||||
| Residual autocorrelation | 0.04 | 0.03 | 0.15 | 0.10 |
| Model complexity (degrees of freedom) | 7.8 | 8.2 | 3.0 | 15.0 |
| Goodness-of-fit, R2 (%) | 54.4 | 56.2 | 9.7 | 15.6 |
| Model fit criterion (AIC) | 34.6 | 33.3 | 509.0 | 490.5 |
Note: AIC = Akaike’s Information Criterion (lower is better), CI = confidence interval, GRR = growth rate ratio, SARS-CoV-2 = severe acute respiratory syndrome coronavirus 2.
↵* Positivity-corrected weekly growth models are missing 2 weeks for test positivity at the national level (n = 49) and missing 10 weeks at the provincial level (n = 269).
↵† The unadjusted model included out-of-home mobility in the previous 3 weeks and a penalized spline for the week.
↵‡ The adjusted model included out-of-home mobility in the previous 3 weeks, a penalized spline for the week and mean temperature in the previous 3 weeks.