Sales of UV light sanitising devices have soared during the coronavirus outbreak, but risk lulling users into an expensive and false sense of security, Rhiannon Williams reports.
While the coronavirus outbreak may have turned us into a nation of hand-washers, when was the last time you cleaned your phone?
While we’ve known for years that phones (and smartphones in particular) are essentially bacteria Petri-dishes thanks to an oft-quoted 2012 University of Arizona study’s disgusting revelation that phones can carry 10 times more bacteria than most toilet seats, it’s taken a global pandemic for us to start giving them a good scrubbing.
Knowing so little about the virus has made it even harder to curb its spread. A report from researchers at Australia’s national science agency published earlier this month alleges that Covid-19 can remain infectious on phone screens and banknotes for up to 28 days, compared to the influenza virus’ 17 days survival stretch. Previous studies had suggested it could only survive between two and three days on glass and up to six days on plastic and stainless steel, leading the team to claim their findings demonstrate that (despite taking place in extremely controlled conditions that don’t represent the real world) SARS-CoV-2 “can remain infectious for significantly longer time periods than generally considered possible”.
The findings are likely to reinvigorate interest in the phone sanitising products that clean handsets using ultraviolet (UV) light, a previously niche industry that’s been reaping the benefits of our new-found investment in hygiene. Of the three types of UV radiation: UVA, UVB and UVC, it’s the latter, with its short wavelength and high energy, that is harmful to microorganisms and breaks apart germ DNA, making it a valuable virus, bacteria and pathogen-killing tool. PhoneSoap, a US company that makes sturdy cases containing UV-C lightbulbs that promises to sanitise the handset while it charges, reported 1,000 per cent revenue growth compared to the previous year in March alone, while popular phone case make Casetify said it had brought forward its own sanitising case to meet consumer demand.
UV light ‘not a silver bullet’
But while UVC light is scientifically proven to kill SARS-CoV-2, according to a September study from Hiroshima University, that doesn’t necessarily mean UV sanitising cases are the silver bullet to keeping your phone germ-free.
A 2017 study from Massachusetts Institute of Technology (MIT) found that UV light was the most effective way to sanitise 100 per cent of bacteria on a smartphone, beating a 70 per cent ethanol spray, a disinfectant spray, germicidal wipes and baby wipes. However, not all UV boxes are created equal. The study’s most effective method was the US-made Flashbox-mini disinfection chamber, which costs approximately $1,300, followed by a £99 PhoneSoap case, which successfully disinfected the phone but failed to entirely kill off some residual bacteria on its case.
Some unscrupulous manufacturers might take advantage of the current climate of fear around hygiene and declare that their light boxes deliver more effective results than they actually do, warns Tautvydas Karitonas, research and development manager at infection prevention and control group Inivos. “Regardless of the method we choose to disinfect the phone’s surface, it’s important to be conscious of the claims being made by the wipe, disinfectant or UV box manufacturer and whether the evidence to back it up exists,” he tells i. “While surface disinfectants are regulated and their makers need to meet specific standards and provide reports to show they’re effective, unfortunately, it’s not the same for UV light cases.”
False sense of security
A cursory search of Amazon for ‘UV phone sanitiser’ returns more than 7,000 products, some costing as little as £7, with many promising a comprehensive sterilisation rate of up to 99 per cent but failing to deliver any proof of testing. “When you’re using UV radiation in a hospital setting to disinfect, there are specific regulations about the power of the lamps and the length of time of the exposure because they’re pretty dangerous,” explains Dr Lena Ciric, an environmental microbiologist at University College London. “It’s difficult to know whether the bulbs in these boxes are of the standard they’d need to be to achieve something similar on a phone. Now the pandemic has made us so much more aware of cleanliness and hygiene, it’s even easier to prey on people’s fears and anxieties.”
Even if a UVC phone sanitising case comes supported with technical data, it can still lead its owner into a false sense of security, thinking they’re better protected than they actually are, cautions Jamie Woodhall, technical and innovation manager at Initial Washroom Hygiene. “The exposure required to be effective to any beneficial extent is unlikely to be found in the majority of available units, unless they can back this up with proper testing. Even if it does work, as soon as the phone comes out of the box it’s at risk of recontamination again – you’re back to square one,” he says. “There’s no real substitute for repeated cleaning and good hand hygiene practices to make sure that both the surface you’re touching and your hands are clean.”
‘No substitute’ for repeated cleaning
The most practical way to clean a device is to use a good quality anti-viral wipe or an anti-viral spray applied with a paper towel on the phone and leaving it to dry, he insists, adding that repeating the process throughout the day is key. “If you’re putting your phone into a sanitising case just once a day, there’s a real risk it’s not going to be effective,” he adds.
Realistically, how often a phone needs cleaning will depend on what you’ve been doing, Dr Ciric points out, saying that unless someone in your home is ill, cleaning your phone multiple times a day when you haven’t left the house is largely unnecessary. “We wallow in our home bugs all day every day,” she says. “It’s more when we’ve been out and about and our phones have come into contact with a surface lots of people have touched, or we’ve touched something lots of other people will have. So, wipe down your phone when you come home, with cleaning products that we know work.
Ultimately, people are led to believe that a gadget will be better at killing germs than the household cleaners we already own, when, in actuality, they’re just as good, Dr Ciric concludes. “If a product is particularly cheap, chances are it’s not going to do anything other than waste your money,” she says. “More than anything, why spend upwards of £80 on a UV light box when you can just use a wipe?”
How to clean a smartphone
The majority of mobile phones can be wiped down with cleaning wipes or disinfectant-covered kitchen roll without damaging the screen, though they should not be immersed in cleaning products.
Apple updated its advice on how to clean iPhones during the summer. Having previously always advised against using cleaning products on its product for fear of ruining screens, it now says 70 per cent isopropyl alcohol wipes are fine to use. Once wiped down, the handset should be left along for five minutes to allow the disinfecting solution to work properly.
“Using a 70 per cent isopropyl alcohol wipe or Clorox Disinfecting Wipes, you may gently wipe the hard, nonporous surfaces of your Apple product, such as the display, keyboard, or other exterior surfaces,” its website advises.
‘Don’t use bleach. Avoid getting moisture in any opening, and don’t submerge your Apple product in any cleaning agents.”