Correlation of ambient temperature and COVID-19 incidence in Canada

Abstract

The SARS-CoV-2 is a novel coronavirus identified as the cause of COVID-19 and, as the pandemic evolves, many have made parallels to previous epidemics such as SARS-CoV (the cause of an outbreak of severe acute respiratory syndrome [SARS]) in 2003. Many have speculated that, like SARS, the activity of SARS-CoV-2 will subside when the climate becomes warmer. We sought to determine the relationship between ambient temperature and COVID-19 incidence in Canada. We analyzed over 77,700 COVID-19 cases from four Canadian provinces (Alberta, British Columbia, Ontario, and Quebec) from January to May 2020. After adjusting for precipitation, wind gust speed, and province in multiple linear regression models, we found a positive, but not statistically significant, association between cumulative incidence and ambient temperature (14.2 per 100,000 people; 95%CI: -0.60-29.0). We also did not find a statistically significant association between total cases or effective reproductive number of COVID-19 and ambient temperature. Our findings do not support the hypothesis that higher temperatures will reduce transmission of COVID-19 and warns the public not to lose vigilance and to continue practicing safety measures such as hand washing, social distancing, and use of facial masks despite the warming climates.

Keywords: COVID-19; Canada; Reproductive number; SARS-CoV-2; Temperature.

Graphical abstract

Fig. 1

Temperature, COVID-19 Cumulative Incidence, and Effective R. Cumulative incidence rate (left) and effective reproductive number (right) hold no significant association with mean temperature. Models are adjusted for precipitation, gust speed, and province. Solid lines and grey areas refer to the linear trend and 95% confidence interval, respectively, of the correlation between cumulative incidence rate or effective reproductive number and mean temperature.