Question

What is vaccine? How is vaccination beneficial for the immune system?

Answer 1

A vaccine is a preparation that improves immunity to a particular disease. It is a biologically prepared product which contains typical agents resembling a microorganism that causes diseases, made from weakened or dead forms of the microbes, one of its surface proteins or its toxins.
Vaccination is the injection of a dead or weakened organism that forms immunity against that organism in the body.