HCoV-43 Is UV-LED Sensitive

Ultraviolet light-emitting diodes (UV-LED) holds a potential to disinfect surfaces with COVID-19, as the human coronavirus (HCOv-OC43) has been found to be sensitive to ultraviolet (UV) light.

COVID-19 has been found to spread not only through respiratory droplets but also through nasal-, oral-, and eye-mucus-contaminated surfaces. Airborne transmission has been suggested, but complete evidence is not yet available. SARS-CoV2 can survive in aerosols for at least 3 hours and up to 72 hours on hard plastic surfaces.

UV radiation is commonly used to inactivate viruses and other pathogenic organisms. UV inactivation can occur by several different mechanisms, including damage to nucleic acids, proteins, or internal production of oxygen radicals. The mechanism of inactivation depends on the UV wavelength. UV inactivation is a manageable form of disinfection, as the UV-LED lights are small, portable, and often battery operated or solar powered.

This study utilized the PearlBeam UV-LED system from AquiSense Technologies to study the effect of UV light on HCOv-OC43. HCoV-OC43 was utilized as a surrogate for SARS-CoV-2; the viruses share similar structures but have several differences that could affect viral protein interactions and functions. HCoV-OC43 has been found to have serological cross-reactivity with SARS-CoV2 N protein but not to the sera of patients with SARS-CoV-2. Ultimately, the researchers believe that SARS-CoV-2 and HCoV-OC43 are similar enough to be reasonable surrogates.

When exposed to UV LED, HCoV-OC43 was inactivated by multiple wavelengths with 267 and 279 nm being the most effective. Longer wavelengths required higher doses to achieve inactivation. Increasing the wavelength to about 300 nm decreased the disinfection effectivity and required a 10-fold higher dose compared with the 280 to 290 nm wavelength to achieve disinfection.

“[O]ur future work will confirm these results by testing the impact of LEDs and their combinations on SARS-CoV-2,” the researchers concluded.

—Audrey Amos, PharmD

Reference:

Gerchman Y, Mamane H, Friedman N, et al. UV-LED disinfection of coronavirus: wavelength effect. J Photochem Photobiol B. 2020;212:112044. doi:10.1016/j.jphotobiol.2020.112044