Volume 30, Number 5—May 2024
Research
SARS-CoV-2 Transmission in Alberta, British Columbia, and Ontario, Canada, January 2020–January 2022
Aubrey D. Kehoe1, Arshpreet Kaur Mallhi1, Charles R. Barton2, Hunter M. Martin2, Christopher M. Turner2, Xinyi Hua, Kin On Kwok, Gerardo Chowell, and Isaac Chun-Hai Fung
Table 1
Estimates for median Rt and percentage change in Rt after implementation of policies and the emergence of COVID-19 variant in 3 provinces of Canada (Ontario, British Columbia, and Alberta) during January 23, 2020–January 27, 2022*
| Policy/variant | Median Rt (95% credible interval) | % Change (95% credible interval) |
|---|---|---|
| Ontario | ||
| Policy label/emergent variant† | ||
| Before A | 1.641 (1.523–1.764) | Not applicable |
| A→B | 1.275 (1.249–1.301) | −22.426 (−28.083 to −16.190) |
| B→C | 0.968 (0.958–0.979) | −24.008 (−25.597 to −22.302) |
| C→D | 1.075 (1.069–1.081) | 10.964 (9.753–12.243) |
| D→E | 1.066 (1.058–1.074) | −0.828 (−1.733–0.131) |
| E→F | 1.023 (1.019–1.028) | −4.021 (−4.854 to −3.145) |
| F→G | 0.867 (0.862–0.872) | −15.232 (−15.841 to −14.556) |
| G→H | 1.150 (1.130–1.170) | 32.629 (30.223–35.067) |
| H→I | 1.027 (1.019–1.035) | −10.789 (−12.515 to −9.077) |
| After I |
1.040 (1.036–1.043) |
1.296 (0.440–2.094) |
| British Columbia | ||
| Policy label/emergent variant† | ||
| Before A | 1.641 (1.505–1.784) | Not applicable |
| A→B | 0.945 (0.889–1.004) | −42.558 (−48.205 to −35.902) |
| B→C | 1.069 (1.043–1.096) | 13.263 (5.929–21.413) |
| C→D | 1.042 (1.032–1.052) | −2.577 (−5.004–0.087) |
| D→E | 1.007 (0.989–1.026) | −3.333 (−5.309 to −1.139) |
| E→F | 1.036 (1.028–1.044) | 2.802 (0.796–4.972) |
| F→G | 0.862 (0.852–0.873) | −16.787 (−17.974 to −15.455) |
| G→H | 1.240 (1.218–1.262) | 43.849 (40.706–46.835) |
| H→I | 0.984 (0.976–0.992) | −20.725 (−22.297 to −19.154) |
| After I |
1.075 (1.069–1.082) |
9.364 (8.235–10.445) |
| Alberta | ||
| Policy label/emergent variant† | ||
| Before A | 1.815 (1.614–2.031) | Not applicable |
| A→B | 1.187 (1.130–1.245) | −34.710 (−42.227 to −25.800) |
| B→C | 1.021 (1.004–1.038) | −13.898 (−17.841 to −9.344) |
| C→D | 1.056 (1.049–1.063) | 3.467 (1.733–5.358) |
| D→E | 0.945 (0.932–0.958) | −10.522 (−11.882 to −9.013) |
| E→F | 1.049 (1.040–1.057) | 10.925 (9.174–12.810) |
| F→G | 0.906 (0.898–0.913) | −13.657 (−14.622 to −12.595) |
| G→H | 1.270 (1.246–1.294) | 40.273 (37.563–42.923) |
| H→I | 0.989 (0.982–0.995) | −22.172 (−23.655 to −20.689) |
| After I | 1.101 (1.095–1.106) | 11.385 (10.452–12.280) |
*Calculations performed by using the instantaneous reproduction number method as implemented in the R package EpiEstim (The R Foundation for Statistical Computing, https://www.r-project.org). The analysis used a γ-distributed serial interval (mean 4.60 days; SD 5.55 days; α = 0.05). Rt, time-varying reproduction number. †The labels are defined in the text and in the captions of Figures 1–3.
1These first authors contributed equally to this article.
2These second authors contributed equally to this article.
Page created: February 29, 2024
Page updated: April 25, 2024
Page reviewed: April 25, 2024
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.