Sunlight neutralizes COVID-19 8 times faster than expected

Researchers at UC Santa Barbara, Oregon State University, University of Manchester and ETH Zurich call for further examination of the ability of sunlight to neutralize SARS-CoV-2 after finding that the most recent study on the subject was not up to par.

The team compared data from a July 2020 study that reported rapid inactivation of SARS-CoV-2 in the sun in a lab, with a theory of coronavirus inactivation by solar radiation that was published a month ago earlier.

They noticed that the virus was inactivated up to eight times faster in experiments than the most recent theoretical model predicted. “The theory assumes that inactivation works by having UV-B hit the virus’s RNA, damaging it,” Paolo Luzzatto-Fegiz, professor of mechanical engineering and senior author of UC Santa Barbara said in a statement.

However, the research team felt that inactivation of RNA by UV-B “may not be everything.” Scientists have speculated that it could be another mechanism involved besides the inactivation of RNA by UV-B rays such as UV-A, the least energetic component of sunlight.

“People think UV-A doesn’t have much of an effect, but it might interact with some of the molecules in the environment,” Luzzatto-Fezig explained. These molecules could in turn interact with the virus, speeding up inactivation.

“So scientists don’t yet know what’s going on,” said Luzzatto-Fegiz; “Our analysis underscores the need for additional experiments to separately test the effects of specific wavelengths of light and medium composition.”

If UV-A is found to be able to inactivate the coronavirus, this could prove to be very fruitful as there are now many types of inexpensive LED bulbs that are even more powerful than natural sunlight. UV-A could also be used to amplify the effect of air filtration systems at relatively low risk to human health.