Toronto: While higher heat and humidity may slow the spread of COVID-19 there is a flip side to this theory. Longer hours of sunlight are associated with a higher incidence of the disease, according to a study. The research has been published in the journal ‘Geographical Analysis’. It indicates that sunny days can tempt more people out even if this means a higher risk of infection. The findings by researchers led by McMaster University in Canada provide a lot of information. It reignites the widespread scientific debate over how seasonal changes, specifically warmer weather, might shape the spread of COVID-19.
Research has shown that pathogens such as influenza and SARS thrive in lower temperatures and humidity. However, little is known about ‘SARS-CoV-2’, the virus that causes COVID-19, the researchers said.
“There is a lot of pressure to reopen economy. Many people want to know if it will be safer to do so in the summer months,” the researchers said. “Restrictions in movement have begun to ease around the world. It will hinge on how SARS-CoV2 will be affected by a change in season,” said Antonio Paez. He is a professor at McMaster, and lead author of the study.
Paez and colleagues investigated climate factors in the spread of COVID-19 in several provinces in Spain. It is one of the countries hardest hit by the pandemic, with more than 270,000 cases.
They combined and analysed data on reported cases of the disease and meteorological information over a period of 30 days. The period was just before a state-of-emergency was declared in Spain.
At higher levels of heat and humidity, researchers found that for every percentage increase, there was a 3 per cent decline in the incidence of COVID-19. It was possibly because warmer temperatures curtail the viability of the virus. The opposite was true for hours of sunshine: more sun meant greater spread, they said.
The researchers speculate the increase may be related to human behaviour, since compliance with lockdown measures breaks down in sunnier days.