Researchers at the University of Santa Barbara, Oregon State University, the University of Manchester and the ETH Zurich call for a more detailed view of the ability of sunlight to neutralize SARS-CoV-2 after finding that l ‘most recent study on the issue was not up to par.
The team compared data from a July 2020 study that reported rapid solar inactivation of SARS-CoV-2 in sunlight in a laboratory, with a theory of coronavirus inactivation by solar radiation that it was published just a month earlier.
They observed that the virus inactivated up to eight times faster in experiments than the most recently predicted theoretical model. “The theory assumes that inactivation works by causing UV-B to hit the virus’s RNA and damage it,” Paolo Luzzatto-Fegiz, a professor of mechanical engineering and lead author at the University of Santa Barbara, said in a statement. .
However, the research team considered that UV-B RNA inactivation “may not be the whole story.” Scientists speculated that there could be another mechanism at play apart from inactivation of RNA by UV-B rays such as UV-A, the least energetic component of sunlight.
“People think UV-A rays don’t have much of an effect, but they could be interacting with some of the molecules in the environment,” Luzzatto-Fezig explained. In turn, these molecules could interact with the virus, accelerating inactivation.
“So scientists still don’t know what’s going on,” Luzzatto-Fegiz said; “Our analysis points to the need for additional experiments to test separately the effects of specific light wavelengths and average composition.”
If UV-A is able to inactivate the coronavirus, this could be very fruitful as there are now many types of low cost LED bulbs that are even stronger than natural sunlight. UV-A rays could also be used to amplify the effect of air filtration systems with a relatively low risk to human health.