To their credit they are also called “deactivated” viruses. The idea is to expose people to the protein coats, so they can build up immunity to those, but have the “Replicate a whole bunch of ME!!!!” DNA or RNA instructions destroyed. But if some of them aren’t destroyed, then you get the flu. Even if they are destroyed, the immune response to the proteins might make you somewhat sick. But if the DNA parts they aren’t destroyed, and you do get sick, that doesn’t make them “alive” - at least by my definition. They still don’t eat, they don’t poop, they don’t metabolize, they don’t reproduce, and their number never increases unless and until they manage to infect some other living thing, which then is subverted into churning out copies of them, instead of doing whatever they were supposed to be doing. A virus is like a sheet of paper that says “URGENT! Copy me, and give the copies to your co-workers to also copy!” that is by the copy machine. If someone just follows instructions they are given, they will set aside what they are doing and will just churn out and distribute those copies, because that’s what they were “instructed” (by the virus) to do. Come to think of it it’s like the “If you send this email to five of your friends, you will get lucky but if you don’t, bad luck will befall you.” Such emails actually require cognitive action on the part of the recipient, as opposed to regular email viruses that act only within the operating system (and indeed which often attempt to conceal themselves from the user). Without the minds of the users, the “send this email to five of your friends” viruses wouldn’t propagate.
If they don’t reproduce where do they come from , and why can’t we eradicate all of them?