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
The coronavirus that causes COVID-19 might have a stronghold on newspaper headlines, but the truth is, it is pretty vulnerable.
Coronaviruses are “enveloped viruses”, which means they have a delicate coating of lipids (or fats) and protein spikes that surround their genetic material. While this coat may play a role in helping the virus infect cells, it can be easily destroyed by soap or disinfectants, inactivating the virus.
To kill a coronavirus
Not all germ-killers are created equal. If you would like to check if yours is doing its job, the National Environment Agency’s interim list of “Household Products and Active Ingredients for Disinfection of the COVID-19 Virus” is a good first stop. It is based on published scientific studies on active ingredients that work against coronaviruses, and in the necessary concentrations.
In addition to ethyl alcohol (70%) and isopropyl alcohol (50%), the list includes non-alcohol ingredients like povidine-iodine (1% iodine), benzalkonium chloride (0.05%), chloroxylenol (0.12%), and sodium hypochlorite (0.05-0.5%).
But while all of them might work against coronaviruses and can be found in everyday household cleaning products, not all of them are ideal for splashing on your hands. Some of the active ingredients work better, for instance, in surgical settings, or as surface cleaners.
Povidine-iodine (1% iodine) or iodine in iodophors (50ppm) are commonly used pre- and post-surgery. They stain the area that has been cleaned, letting surgeons know which part of the patient’s skin is sterile. They are also known to provide a disinfecting effect that lasts the duration of most surgeries. Chloroxylenol (0.12%), too, is commonly used as a skin disinfectant and wound cleaner in surgical settings.
On the downside, a sanitiser that stains may not be ideal for daily use, and chloroxylenol could irritate the skin and be toxic to pets. Similarly, sodium chlorite (0.23%) and sodium hypochlorite (0.05 – 0.5%), commonly found in household bleaches, are tough on germs, but corrosive on skin.
Deadly for coronaviruses, safe for kids
A common active ingredient in non-alcohol hand sanitisers is benzalkonium chloride (0.05%), or BKC, which kills microorganisms or stops their growth. BKC is also found in wound cleaners, disinfecting wet wipes, lozenges, mouthwashes, and spermicidal creams, as well as spray disinfectants for hard surface sanitisation.
BKC is part of a family of active ingredients called Quaternary Ammonium Compounds, or “quats”, which, in concentrations of at least 0.05%, cause the lipid “skin” of coronaviruses to break and its cell contents to spill out, inactivating the virus, explains infectious disease specialist Dr Leong Hoe Nam.
“Alcohol has been traditionally used, and has become the de facto ingredient (in hand sanitisers) because so many companies use it, but BKC can also kill coronaviruses,” he says, adding that it is important that consumers familiarise themselves with which active ingredients work, and how quickly.
While BKC does take longer to dry than alcohol, quats’ germ-killing power for some types of bacteria can linger on the hands for hours. BKC is also non-toxic to children and pets, and less likely to dry or irritate skin since it is gentler on the skin’s natural oils. It is also non-flammable, making it easier to store and safe for use in spaces like kitchens.
But whatever sanitiser you choose, do know that none of them work well on greasy, dirty hands. Nor can they effectively remove some chemicals and viruses like the norovirus, which is a hardier, non-enveloped virus that causes gastrointestinal issues, or spores from bacterium such as C. difficile.
And while hand sanitisers offer a reasonably quick coronavirus kill, the inactivated virus remains on your hands. That’s why proper hand-washing with soap should always be your first choice for a complete kill-and-clean, says Dr Leong.
“Sanitisers are convenient to use but for viruses, nothing beats washing it down the sink.”