[VinnyMS (OP)]

i think viruses have embedded proprieties, like number of infected creatures. if the limit is reached the virus expires. this means we can defeat it in a lab by infecting mice 1 by 1 by 10000. every time a mice is infected by covid-19 its infected by a new version of the covid-19, could be every 3 to 10 mice instead of every 1 mice. when the virus expires we copy its state and we create a vaccine

[evan_au]

There is research ongoing to make gene drives safer by including a "counter" in the engineered gene.
- It's complicated to design, and ensure the counter doesn't get "lost" as cells divide
Listen for the "generation clock" from 30 minutes : http://longnow.org/seminars/02017/oct/30/engineering-gene-safety/
Listen for risks of the control being lost, from 60 minutes.

But a virus genome has little room for a superfluous "clock" gene, and with copying errors, the clock is likely to get broken after a few mutations hitting this gene (ie within a couple of months).
- And a fatal gene is very likely to be selected against

So I think that a "generation clock" gene is unlikely to occur in a natural virus or bacterium  (ignoring the telomeres in larger organisms).

There is a well-known technique for using an "attenuated live virus" vaccine.
- But these vaccines are dangerous to use in immune-compromised people, babies or the elderly (and the elderly are especially at risk from COVID-19)
- I think most people would prefer a vaccine which presents proteins from the virus coat to provoke an immune response, rather than using a live virus
See: https://en.wikipedia.org/wiki/Attenuated_vaccine
-

[Bored chemist]

i think viruses have embedded proprieties, like number of infected creatures.

I don't see how you expect a virus to be able to count.

It's hard to define the lifespan of something which isn't alive.
In principle, deep frozen, the virus would last practically forever.

[alancalverd]

It has been counting bats for thousands of years. There are more viruses than bats, and more bats than humans, so COVID will win any war of attrition. The only way to prevent it infecting more humans is to prevent human-human transmission (and stop eating bats). No new technology required, just a lot of common sense and a realisation that people are more important than politicians.