It would be a vaccination if its terms didn't explicitly depend upon the "virus" itself. The GPL actually imposes limitations on licensed software that wouldn't exist in a system without copyright at all. I would prefer a "true vaccination" rather than a counter-virus, and as such I wrote a license of my own meant to serve that purpose. I now use it for pretty much everything.

It, too, is a "hereditary" use and distribution license. It is not strictly speaking an "open source" license because it applies to more than software: it's intended to apply to any copyrightable work. I've finally "found" a license that I really feel good about applying to things I've authored.

Anyhow, my point is that defining something as "viral" based on the characteristics of copyright does then apply to the GPL as well, precisely because of the way the GPL inherits some of its characteristics from copyright. It takes a license, like the one I created, that creates a sort of "protected public domain", to really innoculate against the viral properties of copyright.