Post-doctoral fellow John Gibson, a member of Professor Ramin Farnood’s group, is the lead author of a recently published paper on the effect of UV radiation on the Delta and Omicron variants of SARS-CoV-2 by the American Chemical Society in their bi-weekly Environmental Science & Technology journal. The paper, titled Exploring the Differences in the Response of Delta and Omicron to Ultraviolet Radiation, provides insight into how these variants, which have dominated the later stages of the COVID-19 pandemic, respond differently than the ancestral strain of SARS-CoV-2 to varying levels of UV radiation when applied as a disinfection technique. The work was conducted in collaboration with Scott Gray-Owen’s team at the Temerty Faculty of Medicine, Natasha Christie at the Emerging & Pandemic Infections Consortium, and Samira Mubaraka at Sunnybrook Research Institute.
At the Combined Containment Level 3 Unit at U of T’s Temerty Faculty of Medicine, SARS-CoV-2 samples were contained in a specially constructed airtight containment vessel to prevent the escape of aerosolized droplets during specimen mixing. Through a quartz window in the vessel, the samples were exposed to culminated UV radiation from a custom-built apparatus provided by Trojan Technologies of London, ON, Canada. Since inactive or noninfective copies of the virus would still have a detectable genome that would register on a qPCR test, the remaining concentration of SARS-CoV-2 was instead measured using techniques that assessed the virus’ ability to infect cells.
The results of this work revealed that a 17% higher UV dose is required to achieve disinfection of the Delta and Omicron variants when compared to the ancestral strain of SARS-CoV-2. This is likely due to a deletion of UV-sensitive pyrimidine bases in the newer variants’ RNA sequences that have left the virus slightly less susceptible to damage from UV radiation. This work has a range of applications, including increasing disinfection success in hospitals and other high-risk environments where COVID-19 disinfection is a priority.
The full paper is available to read here: