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UV Radiation Kills Virus That Causes COVID-19 in Lab, Study Finds

AHA Publisher — Thu, 18 Mar 2021 07:00:07 +0000

Ohio State University via Newswise – COLUMBUS, Ohio – A specific wavelength of ultraviolet radiation killed more than 99.99% of SARS-CoV-2, the virus that causes COVID-19, in laboratory tests, a new study has found. The results could offer an encouraging option for inactivating the virus that causes COVID-19 from surfaces or, potentially, from the air. It is the first study to demonstrate that specific doses of UV222, a relatively short wavelength of ultraviolet radiation, may be a feasible and safe approach to disinfecting COVID-19. The study appears on a preprint server and has not yet undergone a formal peer review by other scientists. “The special thing is that this wavelength is effectively absorbed by the SARS-CoV-2 genome and the proteins of the virus,” said Natalie Hull, lead author of the study and assistant professor of civil, environmental and geodetic engineering at The Ohio State University. “And because of that, it was likely able to damage the proteins that perpetuate the virus infection cycle. And we think that’s why this is so effective.” The findings mean that UV222 could be a safe way to disinfect spaces contaminated by COVID-19, the researchers said. “This is the first time anyone has done something with the real virus, and as best we can tell, this is a wavelength that’s safe for humans,” said Richard Robinson, co-author of the study and associate professor of microbial infection and immunity at Ohio State. “And so theoretically, this could be a way of decontaminating that would be safer for people, and would also kill the virus.” There are caveats to the study. The findings, while encouraging, are “a starting point,” Hull said. The researchers tested the effectiveness of UV to destroy SARS-CoV-2 in a liquid solution, which is usually a more difficult medium to disinfect than air. But the study did not test UV222’s ability to kill the virus in the air or on non-liquid surfaces, and any real-world solution to fighting the virus in spaces where people live, work or play must be effective in those spaces. An open room would include other factors not tested in this study, including varying temperatures, humidity and air flow, Hull said. She said the UV light destroys the proteins and nucleic acids that make up the virus, essentially disabling it. Destroying the proteins and nucleic acids makes it impossible for the virus to replicate and complete the cycles necessary to infect people. “It’s basically like scrambling a protein with heat,” Hull said. “You’re applying energy and it breaks the bonds to change the structure. And these cell processes responsible for replicating the genome and making more virus components or binding to the host cell don’t happen in the same way, so it halts the infection cycle.” The researchers knew that ultraviolet radiation could inactivate coronaviruses, a broad category of viruses that includes SARS-CoV-2. (The common cold, for example, is also a coronavirus; UV radiation has been shown to destroy it as well.) But most commercially available UV lamps emit rays that are long enough to penetrate skin, making them a potential cancer risk. And little information is known about how much UV radiation is necessary to kill SARS-CoV-2. UV222 is a shorter wavelength of ultraviolet radiation than the rays that reach people from the sun, and previous studies have shown that UV222 is not likely to cause skin cancer and other health problems associated with UV radiation. (The “222” refers to the size of the wavelength — 222 nanometers. These wavelengths from the sun are mostly consumed by Earth’s atmosphere before they reach us.) The study was performed on samples of the COVID-19-causing virus that were cultivated and reproduced in a special laboratory on Ohio State’s campus designed to manage biologically dangerous pathogens and viruses. The research team obtained the samples from the Biodefense and Emerging Infections Research Resources Repository, an arm of the National Institute of Allergy and Infectious Diseases. Researchers directed UV222 at samples of the virus held in a liquid suspension, then tested to see how much of the virus was destroyed and how long the UV radiation took to destroy it. They tested times ranging from 15 seconds to 15 minutes. Robinson, who has studied tuberculosis and other lung pathogens and who is associate director of Ohio State’s Biosafety Level 3 lab where the tests were conducted, said he was overwhelmed by what they saw: A near-total destruction of the virus, after only a few minutes. “When we started these experiments last summer, it was at the time when nothing was working to stop COVID,” Robinson said. “And this was so rewarding, because immunologists were still unsure what to do and here was this thing where we could just zap the virus and see this immediate effect.” Hull and Robinson intend to continue testing UV222 in real-world conditions, and Hull said she is optimistic. “We found the virus is really wimpy when confronted with UV222,” she said. “And our findings are a conservative estimate – liquid is this nice place where the virus is much happier than in a room full of air. We don’t know for sure, but I think it’s reasonable to think it might work in the air, too. We need to do the experiments to find out for sure.” This work was supported in part by the National Institutes of Health.

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Study Suggests Natural UV Radiation Protects Against Coronavirus

AHA Publisher — Fri, 10 Jul 2020 07:00:55 +0000

Dr. Liji Thomas, MD via News-Medical Net – A new study by scientists at the University of Edinburgh and published on the preprint server medRxiv* in July 2020 suggests an interesting link between ultraviolet A radiation and deaths due to COVID-19. While this is an observational study, which means that direct inferences cannot be drawn from this finding, it does, however, suggest better strategies for reducing the death rate due to COVID-19. The COVID-19 pandemic is still spreading throughout many countries, and scientists are exploring its risk factors as part of the effort to contain the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Among the variables being considered are seasonal variations, temperature and humidity conditions, and ultraviolet irradiation. These are known to play a role in several infectious diseases already, such as influenza. Ultraviolet, Sunlight and COVID-19 Since the current pandemic has not yet completed one cycle of seasons, all these factors cannot be thoroughly evaluated. However, the level of ultraviolet (UV) irradiation in the atmosphere can be studied in relation to COVID-19 death rates. Previous research by the same team showed that sunlight can reduce blood pressure via nitric acid production, independent of vitamin D levels. Population-wide studies show that increased UV levels are related to lower blood pressure and decreased heart attack rates. This could also cause diabetes and metabolic syndrome incidence rates to fall. The Study: UV and COVID-19 in 3 Countries Since COVID-19 disease appears to have greater severity among people with these conditions, the current study explores the association between ambient UV and COVID-19 deaths in three countries, namely, the USA, England, and Italy. It looks at over 11,000 counties and areas in these countries in three independent data sets, using only those counties where the UV level was below the threshold known to induce significant vitamin D3 biosynthesis in the skin. This threshold corresponds to a monthly mean vitamin D effective UV (UVvitd) of under 165 KJ/m2. This period is termed the UV vitamin D winter and covered the months from January to April 30, 2020. The daily UV irradiance was derived from satellite data, after accounting for atmospheric absorption by water vapor and ozone. The researchers found that the daily mean UVA levels hovered between 450 to 1,000 KJ/m2 across these countries. After adjusting for demographic, socioeconomic, susceptibility, and long-term environmental variables, the researchers arrived at a multivariate analysis outcome. These include the percentage of older people, ethnic composition, low income and poverty indicators, air pollution indicators such as PM2.5, which reflects fine particulate matter in the air, and the susceptibility to infection. The latter was calculated from various factors such as the population density coupled with the percentage of positive tests and exposure in various ways, as by public transport. UVA Reduces COVID-19 Mortality The model shows that UVA levels are inversely related to COVID-19 mortality. The mortality risk ratio (MRR) is 0.73, which reflects a 27% reduction in risk with an increase of 100KJ/m2 in UVA irradiation in the USA. In England and Italy, it is 0.51 and 0.81 respectively, which means a reduction in deaths by 49% and 19% respectively. Overall, therefore, the MRR was 0.68. This effect is independent of both cold temperatures and of whether the UVA ambient levels crossed the threshold for vitamin D synthesis. An interesting finding is that the higher UVA levels produced more significant reductions in mortality risk in countries with a lower average UVA level, namely, England, compared to the USA or Italy, which have higher average ambient UVA. Mechanisms of Action The researchers suggest that UVA may act via several mechanisms. For one, the irradiation may inactivate the virus in airborne droplets and fomites, reducing the rates of spread and the size of the inoculating dose in those coming into contact with infectious material. This would lead to less severe infection. Secondly, UVA induces the release of nitric oxide from the skin, which then enters the bloodstream, causing blood vessels to dilate and reducing the blood pressure. This, in turn, promotes cardiovascular and metabolic health. This produces a reduction in the risk of death from COVID-19 since heart disease, vascular conditions, and metabolic syndrome are high-risk factors. Thirdly, UVA may reduce the replication of the virus. In SARS-CoV, it acts by s-nitrosating the spike protein, which means it cannot bind with its receptor, the angiotensin-converting enzyme (ACE) 2. Both SARS-CoV and SARS-CoV-2 have homologous spike proteins, and hence this action could be present in the latter as well. Fourthly, endothelial damage, and impaired endothelial nitric oxide synthase activity could be the underlying reason for extensive organ damage in severe COVID-19. UVA could reduce this as well, by promoting the photochemical reaction that produces more nitric oxide. Future Research and Conclusion The study concludes, “Our analysis, replicated in 3 independent national datasets, suggests ambient UVA exposure is associated with lower COVID-19 specific mortality.” The next step would be to confirm that this is a causal association. If so, this could be an easy way to reduce the mortality from the pandemic by advising optimal sun exposure. Moreover, the independent mechanisms could be replicated therapeutically, especially those involving circulating nitric oxide. *Important Notice medRxiv publishes preliminary scientific reports that are not peer-reviewed and, therefore, should not be regarded as conclusive, guide clinical practice/health-related behavior, or treated as established information. To read the original article click here.

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