Strep throat is not viral, it's bacterial. You can catch it over and over. Even with virii, the ones that are highly mutable are re-catchable, like the cold, for instance.
If we're getting picky over terminology, then the pleural of virus is viruses. And they mutate not mute, so it should be mutatable. And the cold is not a virus, but a condition called Acute viral rhinopharyngitis or acute coryza. The virus causing the common cold is a serotype of rhinovirus (about 100 known serotypes), a type of picornavirus.
Although I commented on the use of screen protectors above as circumventing the beneficial value of the oleophobic coating, the protector should allow the use of alcohol wipes, that are very effective in decontaminating surfaces. Although sterilization implies that the item would be absolutely free on microbes after treatment, it is unlikely without harsher or longwinded treatments. But for the purposes of very effectively reducing the level of microbes (many viruses and bacteria, and other types) alcohol wipes are cheap, convenient and beneficial.
So, spoil the look of your iphone by using a screen protector, but thereby make it "sterilizable" with the use of alcohol wipes. Phones, like many items, become contaminated through droplets breathed and spluttered out and from fingers. So I recommend cleaning them (and importantly, computer keyboards) on a daily basis, especially if used within a clinical or other area where pathogens might be found at a higher than ambient level.
I have been a professional microbiologist for almost 30 years and an iPhone user for about 6 months. Watch out for the ordinary every day doctors though as they know very little about microbiology (though they know how to treat infections) as shown by the ongoing issues with hospital acquired infections! LOL!
