Question

why is a vaccine effective?

Answer 1

Vaccine is the most effective way to control the spread of any infections disease..It is because of vaccines that dangerous diseases like smallpox have been eradicated from this world.

How does a vaccine work?

A vaccine is generally a preparation of killed or accentuated (weakened) bacteria or virus.It can also be any other antigenic substance taken from the pathogen.It is administered to a healthy person. When a vaccine is given to a person, it elicits an immune response. This leads to production of antibodies and also some of the plasma cells are stored as memory cells.This is called primary response. Whenever the person is exposed to the same pathogen (the vaccine of which is provided),the memory cells identifies the pathogen and a secondary immune response which is more effective than primary response, kills the pathogen and saves the person from the disease.