A trend has developed over the past year or so, pre-dating the COVID-19 pandemic, of smartphone cases and screen protectors adding “antimicrobial coatings” to their burgeoning lists of features.

New cases from big names like Gear4, Tech21, Speck and OtterBox have added the coatings in the hopes of winning the race for people’s purchases. 

Drop protection and scratch-buffering apparently aren’t quite enough to get people excited about new case drops year after year - fair enough. In fact, there’s no downside to an antimicrobial coating, just its main benefit: it can help to inhibit the growth of microbes on your phone case or screen. 

That said, the aforementioned pandemic has thrown questions of hygiene into sharp relief in recent weeks, and we were interested to investigate just what you can actually expect from an antimicrobial case, when it comes to that scarier category of lingering nasty - the virus.

Antimicrobial is far from antiviral

Without beating around the bush, the answer is simple: very little. We talked to an NHS doctor, as well as a microbiologist, and both were clear to spell out that, though those of us without science degrees might not appreciate it, there are differences between products with antimicrobial and antiviral properties. 

As Chris Micklem, a researcher at the University of Cambridge, told us, “it’s important to understand the differences between bacteria, fungi and viruses, and to realise that what may work for one of these things doesn’t necessarily work for the others.”

As Micklem explains, “while there are materials that have been shown to decrease the longevity of certain virus particles on their surface, it is not yet clear whether commonly advertised antimicrobial coating technologies, as sold in their current form, will have this antiviral effect”. 

Of course, COVID-19 is a disease caused by a virus, SARS-CoV-2, and while it might feel obvious, it’s important that people realise an antimicrobial coating isn’t going to do much to combat it. That's largely because a virus isn't a microbe - they're entirely different categories of entity.

To combat a virus, then, as so many health services around the world are reiterating, people should be concentrating on handwashing and social distancing, not relying on potentially ageing coatings on phone cases.

What does a doctor make of it?

Speaking anonymously, a doctor on the frontline of the UK’s NHS reiterated this. When we asked them to review marketing materials detailing antimicrobial coatings on phone cases, they responded: “The claims appear to relate to bacterial colonisation and would therefore be inadequate to protect against COVID. Measures recommended by Public Health England remain the most sensible, and the public should be skeptical of less scrupulous marketing in these uncertain times.” 

To be clear, none of the cases we’ve encountered have claimed that their coatings would do anything to combat a virus. However, it’s also true that customers’ own understanding of terms like “antimicrobial” and “antibacterial” might lead to some ambiguity on this front. 

In fact, one of the world’s foremost manufacturers of antimicrobial coatings has been quick to make sure that people understand this, too. Microban has issued a statement to clarify that its “built-in antimicrobial technologies are effective against a plethora of product damaging microbes, but are not currently proven to have any antiviral properties when built into products.”

Microban’s technology is actually used by Speck cases, to make it clear that its coatings are representative of the ones in question, and the fact that it's been receiving questions on this front demonstrates that some people have been unsure.

That should make it crystal clear, then, that while these cases might represent steps up in terms of cleanliness and grime management, you shouldn’t be under any illusions about their power to help stave off a virus.