Why Hand Sanitisers do More Harm Than Good

3 February 2021. Updated 4 February 2021.

by Dr Irina Metzler, FRHistS 

Hand sanitisers, or hand satanizers as I prefer to dyslexise, are as ubiquitous a part of the pandemic as the masks. Unlike the masks, which will cause mainly individual problems (if you wear a mask, you’re restricting your own breathing, not someone else’s), hand sanitiser use at the level we’ve been seeing for the past 10 months is going to become one helluva headache in the none too distant future. That’s because apart from destroying your own, personal microbiome we’ve got a bigger picture to consider.

Antimicrobial resistance across the board had been getting worse already before the pandemic hit. Already in 2018 it was noted that alcohol-based hand sanitisers in particular were turning bacteria into the next level of ‘superbug’, namely VRE (vancomycin resistant enterococci), one of the leading causes of infections in hospitals.

“We have to be careful about this new trend towards heavy reliance on alcohol-based hand sanitizers. Soap and water should be our number-one protection” – both in hospitals and for personal use. The next question is whether the bacteria will continue to evolve and tolerate higher and higher doses of alcohol – or even stop responding entirely. “Is it possible for these organisms to develop complete resistance to alcohol?” These questions were also raised by researchers years before the advent of SARS-CoV-2 and the ubiquitous little bottles of hand gels.

We’re heading the same direction as with the over-use and misuse of antibiotics, as was reported in the respected journal Nature, which has caused antibiotic-resistant bacteria, the notorious MRSAs, making inflammation in infections not just worse but getting impossible to treat. So not surprisingly the more responsible scientists picked up on this problem early on in the pandemic. Back in April 2020 the consequences of hand sanitiser misuse were already flagged up.

But as with the misuse of antibiotics, the excessive use of cleaning products and hand sanitisers can lead to antimicrobial resistance in bacteria. There’s concern that the sudden overuse in cleaning products and hand sanitisers during the pandemic could lead to an increase in the number of antimicrobial-resistant bacterial species we encounter. This would put a greater strain on our already struggling healthcare systems, potentially leading to more deaths. What’s more, the problem could continue long after the current pandemic is over.

The millions of people using hand sanitisers several times a day (at least, some almost by the minute it seems) are inflating the possibility for microbial resistance. Never mind the particularly cautious types who wash down their entire shopping with antibacterial products, and are exponentially worsening such resistance.

Our attempts to protect ourselves from COVID-19 may also be creating an environment where even more antimicrobial resistant microorganisms can emerge. Given that antimicrobial resistance already causes more than 700,000 deaths a year worldwide, it’s important we act with caution to prevent further impact.

None of this made headline news, but quietly was backed up by another scientist a few months later, in August 2020.

Not only are we increasing the risk of these problems across the globe by overusing hand gels, we may also not be doing anything against the spread of Covid-19]. It seems pointless spending billions on antibiotics, if the resistance to them comes from poor use of chemical disinfectants and hand sanitisers.

That’s just the effect on hands. What about afterwards, once you’re done with it? Where does the spent hand sanitiser end up? Whether washed off surfaces like supermarket trolleys by rain, or off hands when washing with normal soap at home, it all ends up in wastewater. Again, like the concerns over resistant ‘bugs’, the problems of antibacterial sanitising products have been known for years before the Big P arrived. Here’s the view from as early as 2014 on, worth quoting in full for context, since one must assume that few readers know of the importance of bacteria for sewage treatment:

Triclosan is an indiscriminate killer, wiping out bacteria even in places where microbial communities are hard at work keeping us healthy, like sewage treatment plants. Sewage treatment plants often incorporate anaerobic digesters to reduce the volume of waste they have to deal with. Bacteria adapted to an oxygen-free environment break down organic waste, including sewage, to produce small molecules like ammonia, carbon dioxide, and methane (which can be burned as a fuel). … It’s a win-win system, but it won’t work without bacteria—which makes the ubiquity of antibacterial products troubling. Triclosan is one of the most common antibacterial agents, popping up both where you might expect it—in hand sanitizer and anti-acne face wash—and where some you might not—lip gloss, toothpaste, dish soap, gym clothes, even pencils. A lot of that triclosan ends up down the drain and eventually makes its way to a sewage treatment plant. There, it can really mess with the plant’s bacterial tenants, according new data published in Environmental Science and Technology. Beth Mole, writing for Science News, explains ‘in wastewater treatment plants, the omnipresent antimicrobial can sabotage some sludge-processing microbes and promote drug resistance in others.’ The solids that are left over are often spread on fields as fertilizer—antibiotic-resistant bacteria and all.

So again, something that was already getting to be a problem before the arrival of the SARS-CoV-2 pandemic and before millions of people were smothering their hands umpteen times a day in hand sanitisers. In May 2020 one sewage treatment plant in the US noted the detrimental effect of improved hygiene on the one hand for wastewater treatment on the other hand. “The constant scrubbing, hand-washing and sanitizing that is protecting people from the novel coronavirus may also be inhibiting the dirty work of bugs in Liberty Lake. The city’s wastewater treatment plant has noticed thinner bacteria colonies that aid sewage treatment. The phenomenon coincides with government orders to stay home and clean surfaces thoroughly”.

In June 2020 scientists started to look at the applications and implications of chemicals in hand sanitisers and disinfectants, and observed not just that there were associated personal health hazards to people who sanitise their hands frequently, but also the environmental effects:

Hand sanitizers usually end-up being deposited in high concentrations of the constituting chemical residues (contaminants) in the environmental soil and water bodies. High concentration of these chemicals released in the environment could trigger multi-drug resistance. Antimicrobial resistance is obviously a major public health concern globally. The World Health Organization (WHO) reported that about 700,000 people died due to antimicrobial-resistant infections every year. It is further predicted that the death due to antimicrobial-resistant infections could reach 10 million annually by 2050 if no concrete action is taken now.

The authors of this report concluded that there were significant personal health risks to individuals (such as dehydrated skin, irritation, poisoning and cancer among others) from the repeated usage of hand sanitisers, on top of the environmental impacts. 

So instead of throwing the proverbial baby out with the bathwater, consider good old fashioned conventional soap – otherwise we will have another ticking time bomb far worse than the Big P.

Dr Irina Metzler FRHistS is a medical historian and former lecturer at the University of Swansea, as well as a former Wellcome Trust University Award Fellow

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