How do vaccines work to protect the body?

Vaccines function by introducing antigens into the body, which stimulates the immune system to recognize and fight specific pathogens. These antigens can be in the form of inactivated or weakened pathogens, or pieces of the pathogen, such as proteins. When the immune system encounters these antigens, it produces a response, including the creation of antibodies that specifically target the introduced antigens. This process effectively trains the immune system to recognize and deal with future infections more efficiently, leading to immunity without causing the disease.

This method of immunization prepares the body for future exposures, so if the individual is later exposed to the actual pathogen, their immune system can respond more rapidly and effectively, thus preventing the disease from developing. The understanding of how vaccines train the immune system forms the cornerstone of immunization practices used to control various contagious diseases.