For more information on the various active ingredients in common cleaning agents, please visit:
- Allhealth Solutions, the distributor of the liquid concentrate present in the sanitiser solution
- National Environment Agency Interim List of Household Products and Active Ingredients for Disinfection of the COVID-19 Virus
- European Centre for Disease Prevention and Control interim guidance for environmental cleaning in non-healthcare facilities exposed to SARS-CoV-2
Over the last few months, fear has spread around the globe as quickly as the SARS-COV-2, the coronavirus that causes COVID-19. It has sparked panic-buying of hand sanitisers and anti-bacterial wipes for a quick hygiene fix. Yet, few understand what it is that gives these products the ability to disable germs like coronaviruses.
The strength of sanitisers lies in having the right active ingredients, in the right concentration. According to guidelines from Singapore’s National Environment Agency as well as the European Centre for Disease Prevention and Control, disinfectants with at least 0.05% benzalkonium chloride or 70% ethyl alcohol are effective against coronaviruses. Both target the virus in a similar way.
Coronaviruses have an “envelope”, or a membrane of lipids, or fats, in addition to the protein spikes that give them the “corona” in their names. That protective layer helps the virus survive and spread. Fortunately, that lipid skin is also vulnerable – if it is broken or dissolved, the virus becomes inactive, much like a popped balloon.
Good old soap and water is the best combination to do this effectively. The next best option is to use a hand sanitiser with the active ingredients mentioned.
Alcohol-based hand sanitisers are commonly found in hospital settings, because at concentrations of over 60%, alcohol effectively kills a wide range of microorganisms, including bacteria and some viruses. According to local infectious diseases specialist Dr Leong Hoe Nam, this makes them a quick and effective way to protect frontline healthcare workers who meet many patients every day, thus helping to minimise the transmission of microorganisms to patients.,.
For day-to-day use, however, hand sanitisers with other active ingredients, like benzalkonium chloride, or BKC as it is more commonly known, are effective as well, he says.
BKC belongs to a family of active ingredients called Quaternary Ammonium Compounds, or “quats”, which, like alcohol, ruptures the outer membrane of the coronavirus, causing the cell contents to spill out. BKC is used in everything from lozenges and mouthwashes, to spermicidal creams and surface cleaners. Concentrations differ according to the product – in hand sanitisers, 0.05% can render coronaviruses inactive.
When applied to skin and surfaces, sanitisers require time to work. Alcohol takes 15 to 20 seconds, while BKC can take longer. But because alcohol works by drying or desiccation – the same reason it dries skin out – it’s easier to sense when it is done, as opposed to counting down, says Dr Leong. You should also wait till a non-alcohol sanitiser dries before touching your face.
Non-alcohol sanitisers have their own advantages. BKC-based sanitisers, for example, are non-toxic, so they are particularly suitable for little hands that might find their way into little mouths, or if you are worried it might be ingested by your pets. It can also be less drying to the skin – alcohol can strip the skin of sebums and essential oils, necessitating the use of lotions or creams to rehydrate your skin.
Some studies have shown that benzalkonium chloride can have a longer-lasting effect. It is also non-flammable, making it safe to store and use anywhere.
Both types of sanitisers, however, do come with limitations. Some viruses like norovirus are not easily killed by either, and they do not work when your hands are too greasy or grimy. And as Dr Leong points out, nothing is cheaper and more effective at killing a wide range of viruses than the combination of soap and water.
However, both alcohol and non-alcohol sanitisers can help keep coronaviruses well at bay if soap and water are not readily available. Just make sure you have one with the right active ingredients, and you’re in good hands.