The immune system can rapidly eliminate an infection upon re-exposure by leveraging immunological memory, bypassing initial innate and adaptive response stages.

“So, in our bone marrow, we have this ability to make certain cells that can go out when they are called out chemically, they get called out to sites of infection and create antibodies, and then maintain those antibodies in our system, or have a memory of that particular infection so that if the infection comes back again, we can kill it off immediately. And it doesn't have to pass through these multiple stages of first, the innate response, then the adaptive response, taking some time.”