Study Reveals Ultraviolet Light Exposure Has Antiviral Effects on COVID-19 Variants

New research from Cedars-Sinai investigators, recently published in the peer-reviewed journal Photodiagnosis and Photodynamic Therapy, found that narrow-band ultraviolet A (UVA) exposure has antiviral effects on several major variants of SARS-CoV-2, the virus that causes COVID-19.

“We already knew that, at a specific wavelength and bandwidth, UVA is effective against some RNA viruses, like the common cold and coxsackievirus,” said Ali Rezaie, MD, medical director of the GI Motility Program, director of Bioinformatics at the MAST Program at Cedars-Sinai and corresponding author of the study. “Our study sought to understand whether UVA therapy was also effective against some strains and mutations of other RNA viruses, like SARS-CoV-2.”

Researchers studied three COVID-19 variants: Alpha, Beta and Delta. Live viruses were then extracted from patients and exposed to a single dose of UVA. Researchers examined the effects of UVA on each variant, both extracellularly—by directly exposing the virus to UVA while outside of a cell—and intracellularly—by exposing cells that had been infected with the virus to UVA. They found UVA produced benefits in both scenarios, regardless of the variant being studied.

When an infected cell was exposed to UVA, it was activated into an antiviral state, allowing it to fight back against the virus and suppress the pathway that allows the virus to replicate. Additionally, researchers found the dose level used in their study was tolerated well by cells, and there was no indication that the UVA light was causing harm to the cells themselves.

“More traditional modalities against RNA viruses, including antibodies and vaccines, are typically strain-dependent, meaning as the virus mutates, we are constantly chasing the mutations in order to find effective treatments,” said Gabriela Leite, PhD, lead author of the study and a lead project scientist for the MAST Program at Cedars-Sinai. “However, our research found evidence that UVA could potentially be an effective stand-alone or adjunct therapy regardless of the virus strain for future RNA epidemics.”

Rezaie and Leite said that the next steps are to develop more efficient UVA delivery systems inside the body in preparation of clinical trials.  

“History has taught us that viral epidemics are going to happen. We’re going to see future pandemics,” Rezaie said. “When we do, we need to be ready and have every effective tool available to combat these viruses.”

Other Cedars-Sinai investigators involved in the study include Sepideh Mehravar, Mark Pimentel, Ruchi Mathur, Gil Y. Melmed and Gillian M. Barlow. Additional authors include Volha Teagle.

Funding: This study was funded in part by Aytu biosciences and in part by the John and Geraldine Cusenza Family Foundation.

Read more from Cedars-Sinai Discoveries: What Did COVID-19 Teach Us for the Next Pandemic?