Viruses grow just like bacteria at an exponential rate. But where they differ is that bacteria do not need hosts to replicate while viruses do. This means that viruses need to invade the cells and manipulate them in such a way that they get them to reproduce the virus. This process takes a comparatively long time and once the cell releases the viruses, it spreads a whole bunch of them at once. This can perhaps cause the evolution of viral particles to be bit more "burst" like where you have a big growth in a short time span.
But I doubt that really explains it. Usually when you start feeling sick, such as getting the typical chills and body aches, you're feeling your body's reaction to the virus more so than the virus itself. How fast and how hard the body reacts to the infection is dependent on the kind of virus, so it not illnesses will present themselves as sudden.
Polar87 t1_iquxx5z wrote
Reply to Why do symptoms of viral illness come on so suddenly days after exposure? by CoveredinCatHairs
Viruses grow just like bacteria at an exponential rate. But where they differ is that bacteria do not need hosts to replicate while viruses do. This means that viruses need to invade the cells and manipulate them in such a way that they get them to reproduce the virus. This process takes a comparatively long time and once the cell releases the viruses, it spreads a whole bunch of them at once. This can perhaps cause the evolution of viral particles to be bit more "burst" like where you have a big growth in a short time span.
https://www.nature.com/articles/s41598-021-02148-8
But I doubt that really explains it. Usually when you start feeling sick, such as getting the typical chills and body aches, you're feeling your body's reaction to the virus more so than the virus itself. How fast and how hard the body reacts to the infection is dependent on the kind of virus, so it not illnesses will present themselves as sudden.