WHAT'S NEW - COVID-19 Hygiene

COVID-19 Hygiene

By Sean Derrig

We’ve been receiving a number of enquiries recently about all manner of products and services intended to keep COVID-19 at bay. We are always happy to evaluate these on behalf of clients and we’re finding that while there are some good, honest products out there that do the job, there are some which really don’t withstand too much scrutiny . 

Our Top Tips are:

1. The virus – if on hands or surfaces – isn’t difficult to kill. See below for a summary of our recent post on choosing the right products for this.

2. You can’t disinfect dirt – if hands or surfaces aren’t physically clean disinfectants won’t be as effective.

3.If it sounds too good to be true it probably is. 


On that last point we’ve looked at a number of systems that promise supposedly miraculous results but quite a few appear to work by re-writing the known laws of chemistry, biology and physics. Choosing cleaning / disinfection chemicals or hand hygiene products is quite painless if you follow the guide below - but if you’re considering investing in expensive kit that sounds amazing please get in touch and our technical team will happily take a look. 

We aren’t in the business of pushing particular products – but will if we find a game-changer – what we want to do is unpack any science-y claims and separate the snake oil and spin from the legitimate science so you can make better-informed decisions. Remember that the principles of infection prevention control have been around for over 170 years in healthcare and our technical team are well-versed in these so there’s no need for you to reinvent the wheel. A summary of the products post is below; anything else please get in contact for support. It’s what we’re here for. 

Hand Hygiene - Washing

Because the virus is so susceptible to soap and water, hand washing (as opposed to hand rubs / gels / foams) is always the gold standard. Take your time, lather the soap up well and don’t forget the most commonly neglected areas: the tips of the fingers, palm of the hand, and the thumb. And always dry your hands properly; wet hands are far more efficient at spreading germs. There is a standard for bactericidal soaps – EN1499 – but plain soap is perfectly adequate.

Disposable paper has long been the preferred option of infection control specialists (including ours) but there is conflicting advice about warm air dryers and COVID. Manufacturers insist there’s no proof of any risk but what we do know is the air will definitely not be warm enough for long enough to kill the virus - and previous research has shown dryers are quite good at blasting germs around. While there is no hard evidence of a hand dryer being involved in someone having caught COVID-19 an abundance of caution suggests switching to paper if possible. 

Hand Hygiene – Gels and Foams

Hygienic hand rubs are not quite as effective as soap and water but if soap and water are unavailable you need to look for a minimum 60% alcohol in a hygienic hand rub. Non- alcohol rubs / foams are available too; it’s a myth that ‘only alcohol kills it’. Look for the magic number EN1500 on the label – this means it’s just as good as alcohol at killing germs.

Surface Hygiene

The Government advice is to thoroughly clean first with a general-purpose detergent, then disinfect with a solution of at least 1,000 parts per million active chlorine. This is advice is based on how they do it in the NHS, is well-meant but not really very practical. How do you know if the bleach solution (that’s where the chlorine comes from) has over 1,000ppm? Is a two-stage clean really practical? Do you mind everywhere smelling like a swimming pool?

Help is at hand. There are some very common EN standards for disinfectants and there are single-stage cleaning products that both clean and kill germs in a single action. Obviously if a surface is filthy you need to clean it first - you can’t disinfect dirt – but for most cleaning a single stage is fine. Look for the magic numbers EN1276 or EN13697 or EN14476on a cleaning product. Make sure you follow the manufacturer’s instructions re any dilution or dwell times. 

How to Clean Equipment

Take care using water-based chemicals on kit. Can you spray it on cloth / paper first? You might wish to consider an alcohol like isopropanol which will kill the virus but flashes off quickly and leaves no residue. But don’t use an alcohol hand gel – these usually contain various other ingredients such as aloe to stop skin drying out and will leave kit rather sticky. 

Fogging

This sounds like a plausible way to disinfect large areas and indeed it can be. But make sure you assess the need properly. The ‘fog’ is still water droplets – the machine doesn’t magically turn a dilute chemical into something else. ‘Dry’ fogging just means the droplets are smaller. It’s still water. If you’re thinking about fogging – say – a gallery or somewhere else full of sensitive equipment you might want to think twice and use a reputable supplier who understands this. 

Also don’t forget the virus falls to the ground or other surfaces in respiratory droplets under gravity. Fogging is a way to disinfect surfaces efficiently, you don’t need to disinfect the air. 

Ultraviolet Light

UV kills germs. But it needs to be a certain type and intensity of UV (the proper term for the UV dose is the fluence – a term you’ll never need but we’ve included it for fun). Point is the type of UV that will definitely kill germs is also the type that will definitely cause serious eye damage and destroy skin. There are also practical questions such as what about areas in shadow? We have seen clients using a proper UV cabinet designed for dental instruments as an extra step to disinfect earpieces and mics or makeup brushes after they’ve been cleaned with a wipe but the sort of UV ‘wands’ you might see out there are basically novelty items that add very little to a disinfection process. 

Heat

Heat kills germs too. And different types of germ are more or less susceptible to different temperatures and exposure time. Quite a lot of work has been done on the vulnerability of the coronaviruses to heat including the 2003 SARS so we’re not in the dark about this. There are heat cabinets available for thermally disinfecting costume and most of these seem to go up to 60°C. A costume in a cabinet needs time to heat through because air is a poor conductor of heat - that‘s why you can put your hand in a hot oven briefly but you get a burn instantly you touch the metal. We recommend at least two hours at 60°C to make sure garments get up to the correct temperature throughout.

Steam

Yes, steam kills germs too. But not any old steam. In hospitals and labs there are steam ovens called autoclaves and these run at very specific temperatures. They use superheated steam at a minimum of 121°C and 15psi to guarantee disinfection. This is not the same as wafting a steam wand at something. Yes, the coronavirus is not particularly hardy but unless it’s in an autoclave we suggest steam really shouldn’t be a mainstay of your disinfection strategy. 

How Long Is A Surface Protected?

This is a really difficult question and there are some very stretchy ‘residuality’ claims for a number of products out there. How long the virus remains viable does depend on the type of surface but is hugely influenced by temperature, humidity, light and other factors. It’s complicated. Also some studies are looking for the presence of viral genetic material which is not the same as viable virus. And even if a study is testing for viable virus (as opposed to RNA in a PCR test), that doesn’t mean there’s enough to actually infect someone. If you follow the common sense hygiene advice above the viability of the virus on a surface doesn’t really matter; you’ll kill the virus easily and needn’t worry about how long it takes to die of boredom.