Virus World
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Virus World
Virus World provides a daily blog of the latest news in the Virology field and the COVID-19 pandemic. News on new antiviral drugs, vaccines, diagnostic tests, viral outbreaks, novel viruses and milestone discoveries are curated by expert virologists. Highlighted news include trending and most cited scientific articles in these fields with links to the original publications. Stay up-to-date with the most exciting discoveries in the virus world and the last therapies for COVID-19 without spending hours browsing news and scientific publications. Additional comments by experts on the topics are available in Linkedin (https://www.linkedin.com/in/juanlama/detail/recent-activity/)
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SARS-CoV-2 Omicron Variant is More Stable than the Ancestral Strain on Various Surfaces | bioRxiv

SARS-CoV-2 Omicron Variant is More Stable than the Ancestral Strain on Various Surfaces | bioRxiv | Virus World | Scoop.it

The Omicron BA.1 SARS-CoV-2 variant of concern spreads quickly around the world and outcompetes other circulating strains. We examined the stability of this SARS-CoV-2 variant on various surfaces and revealed that the Omicron variant is more stable than its ancestral strain on smooth and porous surfaces. The newly emerged Omicron SARS-CoV-2 variant of concern (VOC) is highly transmissible in humans. It outcompetes other previously known variants and dominates in different geographical locations in recent months (1). Its spike protein has more than 30 mutations compared to the ancestral strain (2). A recent structural study indicates its spike protein is more stable than the ancestral strain (3). This prompts us to hypothesize that Omicron VOC is also more stable on different surfaces. We previously showed that the ancestral SARS-CoV-2 can still be infectious for several days and hours at room temperature on smooth and porous surfaces, respectively (4). Here, we report that Omicron VOC is more stable than the ancestral strain on these surfaces.

 

Previously described ancestral SARS-CoV-2 (PANGO lineage A) and Omicron VOC (PANGO lineage BA.1) were used in this study (56). Their stability on different surfaces were tested using our previously described protocol by us (47). In brief, a 5 μl droplet of each virus (10^7 TCID50/ml) was applied on different surfaces with a dimension of 1×1 cm2. The treated surfaces were incubated at room temperature (21-22°C) for different time points as indicated and were then immersed in viral transport medium for 30 min to recover residual infectious virus. The recovered virus was titrated by TCID50 assays using Vero-E6 as described (47).

When compared to the ancestral SARS-CoV-2, the Omicron BA.1 variant was shown to be more stable on all studied surfaces (Table). At 2 days post-incubation, the infectious viral titres of ancestral SARS-CoV-2 recovered from stainless steel, polypropylene sheet and glass reduced by 99.91%, >99.86% and 99.9%, respectively. No infectious ancestral SARS-CoV-2, except in one out of three treated glass samples, could be recovered on day 4 post-incubation. In contrast, the Omicron variant could still be recovered from these treated surfaces on day 7 post-incubation....

 

Preprint available in bioRxiv (March 10, 2022):

https://doi.org/10.1101/2022.03.09.483703

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Covid Virus ‘Survives for 28 Days’ in Lab Conditions

Covid Virus ‘Survives for 28 Days’ in Lab Conditions | Virus World | Scoop.it

Researchers find SARS-Cov-2 survives for longer than thought - but only under certain conditions. The findings from Australia's national science agency suggest SARS-Cov-2 can survive for far longer than thought. However, the experiment was conducted in the dark. UV light has already been shown to kill the virus Some experts have also thrown doubt on the actual threat posed by surface transmission in real life. The coronavirus is mostly transmitted when people cough, sneeze or talk. But there is also evidence that it can also be spread by particles hanging in the air. It is also possible someone could get Covid-19 by touching infected surfaces such as metal or plastic, according to the US Centers for Disease Control. This is believed to be much less common, however.

 

Previous laboratory tests have found that SARS-Cov-2 can survive for two to three days on bank notes and glass, and up to six days on plastic and stainless steel, although results vary. However, the research from Australian agency CSIRO found the virus was "extremely robust," surviving for 28 days on smooth surfaces such as glass found on mobile phone screens and both plastic and paper banknotes, when kept at 20C (68F), which is about room temperature, and in the dark. In comparison, the flu virus can survive in the same circumstances for 17 days. The study, published in Virology Journal, also found SARS-Cov-2 survived for less time at hotter temperatures than cooler temperatures; it stopped being infectious within 24 hours at 40C on some surfaces. It also stayed longer on smooth, non-porous surfaces than on porous materials such as cloth, which was found not to carry any infectious virus past 14 days. 

 

Prof Ron Eccles, former director Common Cold Centre at Cardiff University, criticised the study and said the suggestion that the virus could survive for 28 days was causing "unnecessary fear in the public". "Viruses are spread on surfaces from mucus in coughs and sneezes and dirty fingers and this study did not use fresh human mucus as a vehicle to spread the virus," he said. "Fresh mucus is a hostile environment for viruses as it contains lots of white cells that produce enzymes to destroy viruses and can also contain antibodies and other chemicals to neutralise viruses.  "In my opinion infectious viruses will only persist for hours in mucus on surfaces rather than days." In a paper published by the Lancet in July, Emanuel Goldman, professor of microbiology at Rutgers University, said "the chance of transmission through inanimate surfaces is very small". He said studies that suggested a significant risk had been designed with "little resemblance to real-life scenarios" Last week Monica Gandhi, a professor of medicine at the University of California, said the coronavirus did not spread via surfaces. ...

 

Study published in Virology Journal (Oct. 7, 2020):

https://doi.org/10.1186/s12985-020-01418-7

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Survival of SARS-CoV-2 and Influenza Virus on the Human Skin

Survival of SARS-CoV-2 and Influenza Virus on the Human Skin | Virus World | Scoop.it

The stability of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on human skin remains unknown, considering the hazards of viral exposure to humans. We generated a model that allows the safe reproduction of clinical studies on the application of pathogens to human skin and elucidated the stability of SARS-CoV-2 on the human skin. We evaluated the stability of SARS-CoV-2 and influenza A virus (IAV), mixed with culture medium or upper respiratory mucus, on human skin surfaces and the dermal disinfection effectiveness of 80% (w/w) ethanol against SARS-CoV-2 and IAV.

 

SARS-CoV-2 and IAV were inactivated more rapidly on skin surfaces than on other surfaces (stainless steel/glass/plastic); the survival time was significantly longer for SARS-CoV-2 than for IAV [9.04 h (95% confidence interval: 7.96–10.2 h) vs. 1.82 h (1.65–2.00 h)]. IAV on other surfaces was inactivated faster in mucus versus medium conditions, while SARS-CoV-2 showed similar stability in the mucus and medium; the survival time was significantly longer for SARS-CoV-2 than for IAV [11.09 h (10.22–12.00 h) vs. 1.69 h (1.57–1.81 h)]. Moreover, both SARS-CoV-2 and IAV in the mucus/medium on human skin were completely inactivated within 15 s by ethanol treatment. SARS-CoV-2 and IAV were inactivated more rapidly on skin surfaces than on other surfaces (stainless steel/glass/plastic); the survival time was significantly longer for SARS-CoV-2 than for IAV [9.04 h (95% confidence interval: 7.96–10.2 h) vs. 1.82 h (1.65–2.00 h)]. IAV on other surfaces was inactivated faster in mucus versus medium conditions, while SARS-CoV-2 showed similar stability in the mucus and medium; the survival time was significantly longer for SARS-CoV-2 than for IAV [11.09 h (10.22–12.00 h) vs. 1.69 h (1.57–1.81 h)]. Moreover, both SARS-CoV-2 and IAV in the mucus/medium on human skin were completely inactivated within 15 s by ethanol treatment.

 

Published in Clinical Infectious Diseases  (Oct. 3, 2020):

https://doi.org/10.1093/cid/ciaa1517

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