A multi-country study from Canada shows that temperature and latitude do not appear to be associated with the spread of the novel coronavirus (COVID-19), but school closures and other public health measures are having a positive impact.
Dr. Peter Jüni, University of Toronto, said, "Our study uses global data on the COVID-19 epidemic to provide important new evidence that these public health interventions have reduced the growth of the epidemic."
The Canadian study surveyed 144 geopolitical states and provinces in Australia, the United States and Canada, as well as countries around the world, with over 375,600 confirmed cases of COVID-19.
To estimate the growth of the epidemic, researchers compared the number of cases on March 27 and March 20, 2020, and determined the effects of latitude, temperature, humidity, school closures, mass assembly restrictions, and social distance measured during the March 7 to 13 outbreak.
To the researchers' surprise, they found little or no correlation between latitude or temperature and the prevalence of COVID-19 growth, and a weak association between humidity and reduced transmission.
The researchers said that we had done a preliminary study that suggested that both latitude and temperature might play a role. But when we repeated this study under more stringent conditions, we got the opposite result. But public health measures, including school closures, social distances and restrictions on large gatherings, are effective.
The researchers note that the study is of direct relevance because many countries are considering relaxing or eliminating some public health interventions, but summer does not slow the spread of the virus. More importantly, the more public health interventions there are, the greater the impact on slowing the growth of the epidemic. These public health interventions are important because they are currently the only measures that can slow the spread of the epidemic.
Previously, a study at the University of Maryland, USA, showed that temperature and latitude may be directly related to the spread and seasonality of novel coronaviruses, i.e., outbreaks caused by novel coronaviruses are mainly distributed along a narrow east-west direction, roughly along the 30°-50° north latitude corridor, with temperatures of 5-11°C and humidity of 47%-70%.
