99.9% fatal to germs; 100% fatal to microphones!
Technorama members are asking (and being asked) many technology questions related to the COVID-19 pandemic, like:
- Can COVID-19 be passed on through a pop-shield, or by touching a console?
- What do you need to know to stay safe in a radio studio, and should you spray everything in sight with disinfectant?
- What is the risk if your shift follows a presenter who knew someone who had met a nurse who had contact with a mate who was in the same room as a COVID-19-positive human?
We’ve covered these and many related topics in the Technorama Q&A Facebook group in this thread and others. But if you’re not on Facebook, or if you missed the discussion, then read on and stay for the ride.
Full disclosure: John Maizels, the author of this piece, is a senior technologist and broadcaster who has done the usual rounds of getting sick and well again. He is President of Technorama, and has cleaned many studios. He also reads a lot and asks many questions. However he isn’t a medical practitioner, and is not a virologist. He is completely fascinated by the science, and is trying to help his colleagues wade through information and disinformation.
The information that follows addresses some technology issues and is presented in the interests of your health and well-being as a broadcaster. The text might contain errors, so feel free to fact-check our fact-checking. Note that the background science has been researched to the best of the author’s ability, and the recommendations are based on good practice from the engineering point of view. E&OE. Views expressed here are not necessarily those of Technorama. This article contains a number of weblinks, including references to Wikipedia articles. These links are included for reference and to be helpful, but the author makes no warranties about the accuracy of information in the links (which could change at any time).
Now that we’ve dealt with caveats, on with the meat.
Executive summary – the management one-pager
This is what’s going on:
- the SARS-CoV-2 Coronavirus is believed to be passed from host to host via droplets of water.
- a virus exists and hangs around best in a cooler, drier environment. Equipment surfaces can be ideal.
- the virus cannot multiply outside the body
- inside the body, a virus multiplies by invading host cells and replicating, and it does that until the process is interrupted by antibodies, or until the host cell (or the host) dies. Anything that kills the virus while it’s active in a host cell also kills the host cell – that’s one of the challenges of virology
- the virus action can be disrupted easily: soap, detergents, and human antibodies mess up the lipid layer that coats the virus and then it can’t bind with a cell
- a radio studio, and in particular a foam pop shield, isn’t necessarily a germ factory, but it could be
- there are many treatments which will kill a virus outside the body, but many of those treatments aren’t friendly to equipment
- more specifically there are treatments which will kill bugs in a pop-shield, but some of those treatments are unhelpful to the microphone and some may also harm you
- sterilisation substances which identify as “antiseptic” are your best bet generally for germ elimination
- detergents and soaps very specifically render coronavirus unharmful
- washing, in soapy water, anything that might contact a coronavirus is a good thing.
- Start with hands, because hands are easy to wash. Wash properly and often.
You do need to know this: what is a virus and how does it work?
COVID-19 is scary because it’s new, we have no natural or herd immunity, and it lurks in dark corners. Most people don’t really understand what a virus is (or they wouldn’t ask for an antibiotic to treat it), which adds to the likelihood that it won’t be treated correctly.
A virus is not a living organism, and it can’t replicate outside a host cell no matter how much food is around. So what is it? In general, a virus consists of an RNA strand, wrapped in protein. Some viruses, such as the SARS virus, also have an outer layer of lipid, an organic molecule which is oily or waxy. In the case of the SARS virus, the lipid layer binds with a host cell and allows the virus to invade the cell. There are other features of the SARS-CoV-2 virus which help it to get to the bottom of the lungs, which is not good for us.
Despite the simplicity of its makeup, a virus works cleverly and elegantly. Once it’s inside the host cell, it tricks the cell into creating many, many replicas of the viral matter, and the viral matter then buds out of the cell. The cell dies, and the expanded amount of virus matter moves on to try to bind with more cells. Unchecked, the virus takes over all the cells nearby.
The SARS-CoV-2 virus attacks the inside of the lungs, which is why the disease is characterised by coughing, shortness of breath, and general disruption of the process which gets oxygen into the bloodstream. The lungs start to fill full of garbage, and become much less effective.
The body’s natural defence for viral attack is an antibody, a protein which can stick to the surface of a virus. Antibodies are very specific, and each antibody can only attack one type of antigen (a virus or bacterium). In the case of the SARS virus, the antibody interferes with the lipid layer of the virus, rendering it unable to attack a cell. However because the SARS-CoV-2 virus is new (“novel”) humans have no existing immunity, and the body has to start from scratch when it’s infected. That’s not good.
You can read more about the viral cycle here – all viruses work more or less like that description.
Outside a cell, the virus sits inert, unable to do anything except wait for an opportunity to transfer into a host. A virus is pretty much just protein and nucleic acid. It has no will, and no drive; its behaviour is opportunistic. If you break the cycle, you eliminate the virus and you stay safe.
Transmission of the coronavirus family (the “vector”) is through droplets of moisture, which must be inhaled, or otherwise passed via a damp passage into the body.
Getting out is easy: all the stuff collecting in the lungs causes the body to trigger coughing as the way of getting rid of it. When you cough, droplets of water (containing the virus) come out of your mouth at speed, and that’s a major vector for spreading the disease. Getting a virus into the next body is a bit more tricky, but your mouth, nose and eyes provide a suitable passage.
That’s where the cycle must be broken and that’s why PR campaigns are focused on how you can prevent the virus from getting into the body in the first place.
What kills the coronavirus outside the body?
Basically any antiseptic will do the trick. An antiseptic is a germ-killing substance, such as a pure alcohol, that can be applied to the skin, and is non-toxic. Very important, that.
But what about…
Two other substances are often confused with antiseptics.
1. an antibiotic is a substance that slows or kills bacteria. Antibiotics have no effect on a virus because a virus isn’t actually alive.
2. a disinfectant is a substance that kills germs and parasites. Disinfectants can cover a lot of ground, and kill a lot of nasty bugs, but they can also kill you.
And here’s a warning: anything will kill you if you have enough of it. Drinking too much water can be fatal, and overexposure to the treatment is a potential problem with antiseptics, antibiotics, and disinfectants. What’s important here is that disinfectants are more likely (than than antiseptics or antibiotics) to be dangerous or even deadly to humans if the concentration of the disinfectant is high enough. Even in lower concentrations a disinfectant can cause annoying symptoms, especially if it’s breathed in or if you have an allergy to one of the active ingredients.
The reminder: antibiotics do nothing for a virus. They will help fight a secondary bacterial infection if you actually have one, but over-use of antibiotics when there’s no need (“Doctor, you must give me something”) is reducing their effectiveness. That’s a different story for another day. Just don’t use antibiotics unless there’s a need.
And now the million dollar question: how dangerous is a broadcast studio?
Normally not very dangerous at all, unless you’re the sort of person who routinely spills coffee into consoles, pokes pens into power points, or annoys the Chief Engineer. But a less-than-spotless studio can harbour bugs.
The SARS virus might live on a surface for a while. It might only be a day or two, but previous studies have found human coronaviruses could theoretically last on a surface at room temperature for up to nine days – especially if humidity, temperature and cleanliness are low. Viruses survive on hard shiny surfaces longer than on soft ones. It is possible for the virus to be transferred from hard or soft surfaces back into the body if you touch the surface and then touch your mouth, nose or eyes. Gloves won’t help because the surface of the glove itself can be a carrier. And studios are places where people typically are in close proximity to each other, which just increases the chances of passing on the bug.
A pop shield (and, indeed, any type of microphone windshield) might be a pass-on vector or it might not. The likelihood of picking up any virus from a foam shield depends on how damp the shield remains, how close you work to the mic, whether you are contacting it with your mouth or hands, whether you’ve created a way for viral matter to jump into your body, and whether the shield contains a virus in the first place (and in sufficient concentration to trigger an infection).
The best protection is cleanliness.
What works to sterilise a studio?
Consoles, hardware and furniture can be wiped with a disinfectant or an antiseptic. Which treatment you use depends on the thing you’re trying to clean, and the nature of the substance. In general, disinfectants contain all kinds of stuff that isn’t friendly to hardware. On the other hand antiseptics tend to be relatively benign to hardware and people. Start with antiseptics if you have any control over what’s used.
Isopropyl alcohol is a good antiseptic, especially when it is pure (beware of stuff labelled “rubbing alcohol”, which might contain other stuff friendly to skin but not equipment, and is probably only 70% alcohol).
Those packet alcohol wipes used for sterilising skin prior to an injection contain isopropyl alcohol and are a good – if expensive – way to clean and sterilise equipment (consoles, CD players, in-ear-monitors, metals and most plastics).
Methylated spirits is ethanol alcohol that is denatured, which means it contains stuff that makes it unpalatable, and indeed unsafe, to drink. Meths is OK on most equipment, but it’s not as pure as isopropyl alcohol and might leave a residue.
And pop shields?
That process works because soap, like a detergent, is a surfactant, and a surfactant interferes with the lipid layer of the SARS virus. Without the lipid layer, the virus can’t invade a cell.
Aha, you say. So THAT’s why the constant advice is “wash your hands”. Yes it is. Soap and detergent is a great weapon in the fight against COVID-19. Washing your hands is excellent.
Washing a pop shield in soapy water is mechanically acceptable, and won’t harm the pop shield, but it will do nasty things to the virus. Plus the pop shield might come out smelling nice and clean.
What about Glen 20 and other spray disinfectants?
The author personally knows of cases where a strongish disinfectant has been sprayed around a studio and into a pop shield.
There are two reasons that spraying disinfectant everywhere is not a good idea. Disinfectants can do nasty things to plastics and foams. Read the label. If it says “don’t inhale” (and the label for Glen 20 says that) then maybe you’ve been given good advice: don’t inhale. So don’t spray where you’ll inhale. And, in general, it takes a lower concentration of disinfectant to annoy your body than a similar amount of alcohol.
If you must use spray on a pop shield, then maybe try “Sterisol”, or a similar substance that is intended for putting on items that you might then put in or near your mouth. You could also try spray-bottle isopropyl alcohol.
Whatever you use, the pop-shield does not need to be soaked in spray for the sterilisation to work. And the foam should be very dry before the next presenter (or you) attempts to use it, so that you’re not inhaling stuff that won’t help your lungs.
Finally, and this isn’t as obvious to some people as you might think: get the microphone out of the way before any treatment. Wiping a microphone down with an alcohol wipe is likely to be safe, but don’t spray a microphone, and don’t spray a pop shield that’s still on a microphone. Your “kills 99.9% of germs” spray product may well kill 100% of microphones, and nobody will love you for that.
Yes – UV radiation kills viruses. Whether that’s useful information in your situation is beyond this article, but it’s included for completeness, and no information is available to suggest that UV irradiation is going to be better than exposure to soap.
A really good approach: lots of pop shields and soap.
If you want to promote best hygiene in a studio, issue every presenter with their own pop shield. Pop shields aren’t expensive, around AUD$20 for a good one, and that’s way cheaper than getting sick. It should be the presenter’s responsibility to wash – and dry – the pop shield between sessions.
Any pop shield is better than no pop shield, especially if the aim is to provide your presenters with a personal barrier. But some cheapo pop shields don’t actually do much to anti-pop, are made of foam which will disintegrate after longer term exposure to air, and react very badly to antiseptics and disinfectants.
A good choice of pop shield is the Rode WS2. This foam shield fits the Rode Procaster, Podcaster and Broadcaster mikes. It will most likely fit an Electrovoice RE20, the Sennheiser MD-421, and any number of classic 1″ condenser mikes (such as the Rode NT1/NT2, Neumann U87, Audio Technica AT2020, and AKG C414). Rode also make a smaller pop shield, the WS3, which fits the Rode M3 and might also fit the AKG C1000 and similar medium barrel mikes. We haven’t tested the shields on all those mics, so your mileage may vary.
Where do you get pop shields at the right price?
A list of suppliers will be added in the next 24 hours. Technorama spoke to Rode late last week, and under normal circumstances we might have been seeking a direct discount deal for members. However the COVID-19 pandemic is just too big for us to take that on.
And there’s another reason for you to make your own purchase: this is the right time for you to approach your local dealer and get your supply from an existing retail or professional outlet. Every outlet needs business right now, and buying locally is the right thing to do. And feel free to say “Technorama sent us”.
Who sells pop shields?
This incomplete list was assembled from contacts in the industry; it can’t possibly be complete, but it’s a start. Information provided here is in no particular order, and no recommendation should be inferred – we are simply providing some contact points as a service to members and readers.
If you have a favourite pop shield dealer who should be on this list (and has stock and/or can supply product in quantity) please drop a line to john AT technorama org au (you know the deal with addresses) and he will update the list.
Is any pop shield better than any other? Marginally, but it’s way beyond our capacity right now to test or recommend. Brand-name pop shields are likely to last better, and will most likely be made of a foam that is both more robust and actually does the job it’s supposed to do: stop pops. Not every piece of foam works or sounds the same, and you will find cheap pop shields which muffle the audio and still don’t stop popping.
We do know that Rode has a fine product, it tests well, the company is Australian and worthy of support, and the market price per unit is around $20 or lower. Those are all good recommendation points.
|Brisbane Sound Group||Brisbane|
|Store DJ/Mannys Music||Sydney, Melbourne, Brisbane, Perth|
|DJ City||Sydney, Melbourne, Brisbane|
|Lemac||Sydney, Brisbane, Melbourne|
Article last update: 12:30 2020-03-17