I think "disease" would be a decent description. "Virus" carries way too many implications about things like communicability and origination that clearly don't apply.

I'd say it's more like cancer: lots of stuff influences it, and you can make yourself a lot safer, but it's ultimately fairly random and anybody can fall victim to it. You can't catch it from other people, you can't get vaccinated against it, surviving it doesn't give you any immunity for the next time, better surgical and other medical techniques are making it more survivable.... One big difference, of course, is the age factor.