One universal antiviral to rule them all?

Interesting, and potentially very good. But I can't help but wonder, like at least one other commenter, that this might have unexpected effects if applied at a larger scale. I know some viruses kill bacteria for instance. I don't know, something about universal applicability makes me a little uneasy.

Bacteriophages don't infect things which aren't bacteria.

In fact they're so absurdly specific that while you could bathe in a solution of them and not get sick, they also frequently fail to infect slightly different members of the same species, which is why ultimately they never become antibiotic alternatives: having the right one on hand ranges from difficult to impossible.

Are you saying that this antiviral would not kill bacteriophages? Or are you saying you think the effect would be small because the population in our bodies is small?

There are not bacteriophages in your body, except where bacteria are. And since they don't infect human cells, they're being constantly destroyed already by the primary immune system even if they get there.

Viral infections only successfully persist by replicating faster then the human body destroys them, and by hiding in human cells.

This isn't a system which is some sort of toxic to viruses, it's an immune booster.