Does a vaccine work on someone who is already sick? Why?

No, because the immune system is already battling with the virus or disease

Im guessing a vaccine does work on someone who is already sick from the disease. For example, if someone who had corona virus took a vaccine that everyone’s getting now and I believe it does work to cure the patient from the sickness. It depends on what the vaccine does to you though.

It may have some of the same features that it’s mother does but, it may have some of the same features that it’s father has as well.

Ur very welcome for