New research has shed light on how natural variations in UV radiation influences the spread of COVID-19. Researchers from Harvard University, Jonathon Proctor, together with co-authors Peter Huybers, also at Harvard University, Tamma Carleton and Kyle Meng from the University of California Santa Barbara and Jules Cornetet at France's École Normale Supérieure Paris-Saclay have published their findings in the Proceedings of the National Academy of Sciences. The researchers found that the spread of COVID-19 tended to be lower in the weeks following higher UV exposure. Recent laboratory studies demonstrated that UV inactivates SARS-CoV-2 on surfaces.
"Understanding the potential seasonality of COVID-19 transmission could help inform our response to the pandemic in the coming months," said Jonathan Proctor, a postdoctoral fellow at the Harvard Data Science Initiative and the Harvard Center for the Environment. "These findings suggest that the incidence of COVID-19 may have a seasonal pattern, spreading faster in the winter when it's darker than in the summer."
"We basically ask whether daily fluctuations in environmental conditions experienced by a population affect new COVID-19 cases up to two weeks later," Meng explained.
While this research shows that COVID-19 exhibits a seasonal pattern due to changes in UV, the full seasonality of COVID-19 influences from other environmental factors such as temperature and humidity.
"We are confident of the UV effect, but this is only one piece of the full seasonality picture," Carleton said.