How does vaccine work?

Vaccines work by stimulating the immune system to produce an immune response against a specific pathogen, such as a virus or bacteria. When a vaccine is administered, it contains either weakened or inactivated forms of the pathogen, or proteins from the pathogen that trigger an immune response.

The immune system recognizes these foreign substances as a threat and produces antibodies to attack them. These antibodies remain in the body and provide immunity against future infections by the same pathogen. This means that if the person is exposed to the actual pathogen in the future, their immune system will be able to recognize and fight it off more effectively, preventing illness or reducing the severity of symptoms.