Question

How does the immune system respond to a pathogen that a person has been vaccinated against?

Answer 1

Immunity is a type of resistance that is present naturally or acquired by an individual to develop a pathological condition after having an infective dose of virulent pathogen, its toxin and allergens. A vaccine trained the immune system for responding against the pathogen.

Complete answer:
When a pathogen enters the human body they start to multiply and cause illness, its effect reduces by the immune system by fighting the infections. When the body immune system does not work properly against any infection then vaccination is provided to develop the immunity which sometimes leads to the occurrence of minor symptoms like fever, chills, body ache etc, these symptoms help to develop immunity, with the supply of memory T-lymphocyte and B-lymphocytes, which helps to fight with the infection in future.

Additional Information:
Immunology deals with the study of the immune system and its response and it is discovered by Edward Jenner and who is also known as the father of immunology. Immunity is of mainly two types innate and acquired. Innate immunity is natural which develops by birth and it is always present in the body and helps in protection against infection. Acquired immunity develops resistance to disease during a lifetime which can be short-lived or life long.

Note:
Sometimes the body responds against infection rapidly after vaccination but sometimes it takes time to produce the lymphocyte which leads to the occurrence of disease. Therefore sometimes after vaccination a person also develops a disease which leads to the conclusion that the person who becomes vaccinated doesn't need to be safe.