Canadian study: Climate and latitude have no effect on coronavirus

A Canadian study looked at 144 geopolitical areas (states and provinces in Australia, the US and Canada, as well as various countries around the world) and a total of more than 375.600 confirmed cases of COVID-19. China, Italy, Iran and South Korea were excluded because the virus was in decline in the case of China or in the midst of a pandemic at the time of the analysis in others.

To estimate the growth of the pandemic, the researchers compared the number of cases on March 27 to the cases on March 20, 2020. They then determined the influence on the coronavirus of climate, latitude, temperature, humidity, school closures, mass gathering restrictions, and social distancing measured during the exhibition period from 7 to 13 March.

The results seem to leave little room for interpretation: little or no association between latitude or temperature with the epidemic growth of COVID-19. Only a weak association between humidity and reduced virus transmission. The results, especially those showing the lack of influence of the warmer climate on the progression of the pandemic, surprised the authors.

“We had conducted a preliminary study according to which both latitude and climate could play a role on the coronavirus”, says Dr. Peter Juni. “But when we repeated the study under much more rigorous conditions, we got the opposite result.”

The researchers found that public health measures, including school closures, social distancing and restrictions on large gatherings, were effective.

“Our findings are of immediate relevance as many countries, and some Canadian provinces and territories, are considering relaxing or removing some of these public health interventions,” says Jüni.

“Summer won't make it go away,”

This is what Prof.ssa says Dionne Gesink, co-author and epidemiologist of the Dalla Lana School of Public Health. “It's important for people to know this. On the other hand, the more public health interventions have taken place in an area, the greater the impact on slowing epidemic growth. These containment measures are really important because they are the only thing that works right now to slow the epidemic.”

The authors note several study limitations, such as differences in testing practices, inability to estimate actual COVID-19 rates, and compliance with social distancing.

When deciding how to lift restrictions, governments and public health authorities should carefully weigh the impact of these measures against potential mental and economic health harms and benefits.