I've noticed that after close contact with those who get frequent shots and boosters I acquire phlegm in the back of my throat for a few days following. I'm pretty sure they are shedding, and if I take antibiotics the phlegm goes away. I've never had COVID, and no one close to me has ever tested positive. Is there a window when shedders are more contagious, or is it continuous because they are boosting on a regular time frame? I can't find much online profiling the shedding process and what to expect.