Exploring the Differences in the Response of SARS-CoV-2 Delta and Omicron to Ultraviolet Radiation

Abstract

One method that can help slow the spread of coronaviruses is disinfection with UV light. The Delta and Omicron variants of the COVID-19 virus (SARS-CoV-2) have come to dominate the later stages of the pandemic due to their higher rates of transmission. In this work, it is shown that a 17% higher UV 254 dose is required for the disinfection of Delta and Omicron variants when compared to the ancestral strain of SARS-CoV-2. The UV 254 disinfection rate constants for SARS-CoV-2 and the Delta and Omicron variants were found to be 1.4 ± 0.3, 1.1 ± 0.2, and 1.1 ± 0.2 cm 2 /mJ, respectively. The rate constants of Delta and Omicron were statistically different from the ancestral strain of SARS-CoV-2 at the 95% confidence level based on at least three replicate experiments. It is suggested that the reason for this difference is the absence of repeating uracil (U) bases in the genome of the two variants. The UV 254 sensitivity of repeating pyrimidine bases is well-established. There are 2.6 and 3.7% fewer uracil triplets (UUU) in the Delta and Omicron variants, respectively, when compared to SARS-CoV-2. This difference in UV 254 sensitivity is relevant to a range of UV disinfection applications including upper-room disinfection, air handling equipment, aircraft sanitization, and others.

Wastewater-Based Epidemiology for Viral Surveillance from an Endemic Perspective: Evidence and Challenges

“…However, the seasonal trend tended to disappear in 2022, suggesting the emergence of new variants potentially more resistant to environmental conditions (e.g., high temperatures, UV rays). Such an observation is supported by the work of Gibson and colleagues [50], who observed that a 17% higher dose of UV254 is required for the disinfection of Delta and Omicron variants compared to the ancestral strain of SARS-CoV-2. In fact, in our study, the SARS-CoV-2 concentration did not vary much across seasons during 2022, showing a constant trend more similar to endemic situations, thus suggesting a possible transition of SARS-CoV-2 from an epidemic to an endemic situation, at least in the region under study.…”

Estimation of the UV susceptibility of aerosolized SARS-CoV-2 to 254 nm irradiation using CFD-based room disinfection simulations

“…As mentioned before, differences in relative humidity, aerosol size distribution and composition may influence the UV dose received by individual viruses and their inactivation process 28 , 60 , 61 . Furthermore, studies on multiple variants of SARS-CoV-2 have indicated differences in UV sensitivities between variants 62 – 64 .…”