If I touch that surface or object could I get sick from the virus, SARS-CoV-2 that causes the disease, COVID-19? That's the aim of this podcast to review what we know about airborne and surface transmission. SARS-CoV-2 is a virus, so it's technically not alive...but if the viral RNA ends up on a doorknob or on an extractor fan, then you could unknowingly come into contact with it. This is called fomite transmission. Today's episode reviews what we know about the survival of the virus on inanimate objects. We find that it survives less well on copper surfaces and longer on plastic than on cardboard. It can also be cleaned from the hospital rooms of patients diagnosed with the virus. But, if the room is not cleaned, then the virus can remain on many typical touch surfaces. There is even a link with fecal shedding and the toilet.
Next, I review the data from The Diamond Princess where it was found that the virus could be recovered from. Cabins after 17 days. That's a long time to remain infectious. What can you do? Well, there's a US EPA site that lists all the disinfectants that should work for SARS-CoV-2 against COVID-19 and I review some of the typical ones and their efficacy.
The slide below shows you a summary of what we know about how long the coronavirus can remain stable in the air and on surfaces. This paper covered the aerosol and surface stability of the SARS-CoV-2 virus on typical surfaces like cardboard, stainless steel, and plastic.
Now let's look at some typical decay curves for the time (in hours) on several different types of materials including copper, cardboard, stainless steel and on plastic. The top panel shows the most recent coronavirus (in RED), while the bottom graphs show the earlier SARS-CoV-1 (in BLUE).
When you're reading the x-axis, bear in mind that the tick marks show Hours (hrs). Therefore you can follow along with the decay in viability to the end of the experiment, which was at the 80 hr point - which is over 3 days! That's a long time to maintain viability, don't you think?
Cruise ships have long been known to be ideal places for outbreaks of infectious diseases. This is mainly due to the large numbers of people who are in close proximity to each other, the opportunity for consumption of contaminated food or water and the fact that the median age of cruise passengers is over 45 years old. This means that many persons could also suffer from other medical conditions that could exacerbate the potential for infections.
Of course, I keep being asked what is the best way to clean suspect surfaces. I am referring people to the USA EPA List N. I'm sure some Australian expert sites will emerge on this topic, but this site allows you to look up the active ingredient and see if it's likely to work.
I've also just discovered a new paper that appeared in the Global Biosecurity journal that provides a mini-review of the disinfection measures that work for SARS-CoV-2. Its a great paper and free to read.
The Breaking News section of this podcast discusses how nanofibrils of cellulose have been used to change the way building composite boards are produced. This is a great example of materials science and the search for replacements for formaldehyde. Who knows, these new 'green' manufacturing methods may also confer other benefits like antibacterial/anti-fungal properties due to the inclusion of boric acid.
The last paper, I want to highlight comes out of Hong Kong and looks at seasonal influenza and how RNA could be recovered from the tops of bookshelves and door handles. The levels were low, but the authors postulate that fomite transmission might exacerbate childhood influenza illness and propagation. This is an important topic since childcare centres have been identified as coronavirus hotspots and have appeared in the news in the past weeks. It's also been claimed that potentially up to 80% of children are infected but are asymptomatic according to one report from New York City.
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Dr. Cameron Jones
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Aussie newsagent bans cash over coronavirus fears | A Current Affair. https://youtu.be/qSjKM2qOYNk
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