Following COVID and having watched far too many zombie movies, I started thinking about an optimal design for a biological weapon. Symptoms wise I believe a modified version of rabies sounds interesting. Mission specific modifications could be made adjusting parameters like aggression, lethality vs permanent neural damage and so on.
However, given the set of symptoms a lot or effort will be put into preventing the pandemic which I want to create. Thus the viruses nature should not be immediately obvious. I first considered giving it a long incubation period, and allowing it to get infective as early as possible. While this might be effective, I considered a more vicious option.
A virus that is deployed in a rather harmless form, with just enough symptoms to ease it's spread and that changes it's nature a few months after the deployment in every infected individual nearly simultaneously. Specifically I wonder about the possibility of a molecular timer that starts at t1 and as it replicates stays at t1 - tpassed until it triggers the viruses change.
I am aware of telomeres, which do effectively have such a timer. However I wonder if something like my weapon could plausibly be build. Are there other know ways to do this in molecular biology?