Question

Explain the principle on which 'vaccine' works.

Answer 1

1. In the main response, the immune system produces antibodies tailored to the antigen contained in the vaccine.
2. Additionally, memory cells are generated, which are specialised immune cells that retain recognition of the pathogen's antigen.
3. When an individual is exposed to the same pathogen again, memory cells detect the antigen and trigger a strong immune response, known as the secondary reaction.
4. The secondary reaction is more quick and effective than the original response, resulting in long-lasting protection against the infection.