Why doesn’t a person get sick twice with some diseases?

A natural reaction to any disease for a person is the production of antibodies, special compounds, whose task is to neutralize viruses and infected cells. After recovery, antibodies from the body do not disappear anywhere and still live in it for some time, which is why, if a person is completely cured of a cold, then the chance of getting sick with it again, after a short period of time, is practically zero. For some diseases, antibodies last a very long time (such as chickenpox), so they remain in the human body for life, preventing the possibility of re-infection.