A new study points out that sunlight is capable of inactivating the coronavirus much faster than previously thought, although the research is still in a premature phase.
There are still no overly convincing theories about whether sunlight is capable of deactivating the coronavirus, something that was initially said not to be, but that more recent theories seem to ensure that certain solar rays could be the best deactivator and, therefore, be used by doctors and health companies to end the virus prematurely.
Now the mechanical engineer from UC Santa Barbara, Paolo Luzzatto-Fegiz and its partners have noticed that the SARS-CoV-2 virus is inactivated up to eight times faster in experiments than previously stated with theoretical models. They explain that “the theory assumes that inactivation works by causing UVB rays to hit the RNA of the virus and damage it,” but it appears that more than that is going on.
And it is that part of the ultraviolet light of the spectrum is absorbed by certain nucleic acid bases in DNA and RNA, although it does not work exactly with all types of ultraviolet light that exist. The longer ultraviolet waves called UVA do not have enough energy to cause problems, but we must stop especially in the calls mid-range UVB waves that are primarily responsible for killing microbes.
Some human coronaviruses, such as SARS, can last for days on surfaces. But one expert says the new coronavirus is more likely to last “from hours to a day or so.”
Shortwave UVC radiation has been shown to be effective against viruses such as SARS-CoV-2. But these UV rays do not usually come into contact with the Earth’s surface thanks to the ozone layer, so nature, directly, cannot help us to end the pandemic. They claim that UVC is great for hospitals, but not for other environments as it could end up producing harmful ozone.
In July 2020 a study tested the effects of ultraviolet light on SARS-CoV-2 in simulated saliva and the virus was inactivated when exposed to simulated sunlight for between 10 and 20 minutes. This study found that the SARS-CoV-2 virus was three times more sensitive to UV rays in sunlight than influenza A, and 90 percent of the coronavirus particles were inactivated after just half an hour of exposure to sunlight in summer.
To this must be added that an independent team carried out a series of environmental calculations that concluded that the RNA molecules of the virus are being photochemically damaged directly by light rays. “The experimentally observed inactivation in simulated saliva is more than eight times faster than would have been expected from theory,” says Luzzatto-Feigiz.
Apple has updated the technical support page where it explains how to disinfect an iPhone or an iPad, to combat the coronavirus.
In any case, there are many doubts about this theory and the researchers are suspecting that it is possible that instead of affecting the RNA of the virus, these long-wave UVA rays may be interacting with molecules in the test medium (simulated saliva) in a way which is capable of accelerating the inactivation of the virus.
In short, they could end up taking advantage of UVA rays to fight SARS-CoV-2, so that medical teams could bet on various types of sunlight to inactivate the virus faster.