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Infectious Diseases

Updated 11 May 2020

Cellphones are 'Trojan Horses' for viruses, study finds

Several studies found that cellphones not only carry bacteria, but they also carry various fungi and viruses.

Cellphones carry all kinds of germs, a new study finds, and researchers say phones should be cleaned regularly to cut the risk for coronavirus transmission.

The advice follows a review of 56 studies that looked at the risk of cellphones being contaminated with bacteria, fungi or viruses. The investigations were conducted across 24 countries between 2006 and 2019, prior to the advent of Covid-19.

The review shows "that mobile phones not only carry bacteria but also viruses, fungi, and protozoa in the thousands", said study author Lotti Tajouri, an associate professor of genomics and molecular biology at Bond University in Queensland, Australia.

On average, the review found that 68% of the mobile phones had been contaminated with a wide range of microorganisms. And some of those contaminants showed resistance to standard antibiotics.

Particularly receptive hosts

The investigators did not conduct any new tests to search for the presence of the Covid-19 virus on phones. However, Tajouri said his team "hypothesise strongly that mobile phones are responsible for the rapid propagation of COVID-19".

Why? First of all, "the virus responsible for Covid-19 can live on glass, plastic, stainless steel for days," Tajouri noted. And cellphones, he added, are "particularly receptive hosts for germs simply because we first never wash them, and we take them everywhere and all the time with us."

That includes where people eat, where they sleep, and where they go to the bathroom, he observed, as well as onboard the planes and trains people use to travel the globe.

And while acknowledging that all everyday objects are contaminated in some way, Tajouri warned that "mobile phones are like international ambulatory five-star luxury hotels" for germs. In fact, he said, "no other type of everyday object can compete".

That point was seconded by Dr Stephen Berger, co-founder of Global Infectious Diseases and Epidemiology Network (GIDEON) in Tel Aviv, Israel.

"Cellular phones are ideal vehicles for the virus of Covid-19," he agreed. "They are repeatedly exposed to material exhaled from our mouth and nose, and spend literally hours in our rather filthy hands. Viruses of this type are known to survive on plastics and stainless steel for two to three hours; on aluminium for two to eight hours; on cardboard and paper for up to 24 hours; and on ceramic or glass for up to five days."

Phones like our 'third hand'

But Tajouri and Berger part ways when it comes to what we should do about it.

Tajouri's advice: "Before you wash your hand, wash your phone," he recommended.

"To be safe, every single one of us needs to first acknowledge that mobile phone is a source of microbial contamination," he said, and to effectively treat phones like "our third hand".

"You could do that by using a soft microfibre cloth with 70% ethanol or use of a non-abrasive disinfectant wipe to wipe off your phone," said Tajouri, though he cautions users to consult phone manufacturers to identify cleaning products that are safe for electronic devices.

By contrast, Berger – who was not involved in the review – suggests keeping your eyes on the real culprit: your hands.

As a practical matter, he said, cellphones are shared about as often as a drinking straw. "And if the phone has been exposed only to your own hands and your own mouth, the potential for viral transmission vanishes," Berger noted.

No need for compulsive cleaning

So, while he "would certainly avoid using the cellphone of a casual acquaintance, even while wearing a mask", Berger said repetitive phone cleaning is unwarranted.

"Bottom line, there is no need to compulsively clean cellphones, or [for that matter] doorknobs, home railings, paper money, eyeglasses, hats, shoes, credit cards, or wristwatches," Berger said. "Whenever these and other objects in our daily life are examined in the laboratory, a veritable 'zoo' of bacteria, parasites, fungi and viruses is discovered. But the common denominator for all of these is the human hand that touches them, and then goes to our mouth or nose."

So it's your hands, said Berger, rather than the phone itself, that "should certainly be thoroughly cleaned. As often as possible."

The review was published online recently in the journal Travel Medicine and Infectious Disease.

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Image credit: Rob Hampson, Unsplash