Hand sanitiser can kill coronavirus, but its overall effectiveness very much depends on the type you use.
Homes, businesses and schools across the UK are potentially using hand sanitisers that can take up to two minutes to kill the virus, as opposed to the standard 20-30 seconds – and could be less effective, too, a Sky News investigation found.
There are two key types of hand sanitisers: those with alcohol in them, and those without. And experts agree you want to be opting for the former, as alcohol has historically been pretty effective at killing coronaviruses.
The coronavirus has a lipid envelope which protects its structure. When you use an alcohol-based hand sanitiser, the alcohol affects this structure and, in doing so, deactivates the virus. When a person rubs it into their hands, it’s essentially reducing the virus to a safe level so you won’t be spreading it around elsewhere.
Alcohol-free hand gels, on the other hand, are thought to be less effective at reducing the germs on your hands – and they can take some time to kick in.
Professor Sally Bloomfield, honorary professor at the London School of Hygiene and Tropical Medicine, explains these hand gels are considered effective providing you’ve had them on your skin for two minutes. In contrast, alcohol hand rubs have been found to work in 20-30 seconds.
“You do not want to have to stand outside the supermarket for two minutes [while it kicks in],” she tells HuffPost UK. The testing process of such hand gels has also been called into question. “Maybe these sanitisers which are non-alcoholic are effective, but at the moment we have not been given sufficient data to make that judgement,” she continues.
“If somebody asked me to recommend a hand sanitiser, I would say: you should use an alcohol-based hand sanitiser which contains at least 60% or more of ethyl alcohol.”
Dr Manal Mohammed, an expert in medical microbiology at the University of Westminster, writing for The Conversation, explains why alcohol-free hand rubs don’t work as well: “Alcohol-free hand sanitisers contain something called quarternary ammonium compounds (usually benzalkonium chloride) instead of alcohol. These can reduce microbes but are less effective than alcohol.”
Studies back up Prof Bloomfield’s recommendation to use a hand sanitiser containing 60% or more alcohol – and this is also in line with guidance from Public Health England (PHE) and the World Health Organisation (WHO).
In the US, the Centers for Disease Control and Prevention (CDC) also advises against alcohol-free rubs. Hand sanitisers with less than 60-95% alcohol may not work equally well for different types of germs, it says, and may merely reduce the growth of germs rather than kill them outright.
It’s worth remebering that you should only use hand sanitiser if soap and water are not available. This is firstly because soap and water are more effective at combatting the virus, but also because while hand gel does contain emollients to protect the skin from the alcohol, overuse will dry your skin out.
But, if you’re caught on the hoof, an alcohol-based hand gel will work fine.
Just make sure you rub it in for 20 seconds. “We know from a collection of publications that if you use 60% or more alcohol hand rubs or sanitisers, then that is effective in terms of reducing the coronavirus to a safe level,” Prof Bloomfield says.
The WHO recommends people store alcohol-based hand sanitisers out of reach of kids. This is because they can be poisonous if ingested. Kids can still use them though – the WHO recommends teaching children how to apply sanitiser safely and to generally monitor their use.
This article originally appeared on HuffPost UK and has been updated.