Immunological memory of adaptive immunity ensures that vaccination effectively prevents disease
When the adaptive immune system is exposed to a new threat, the specifics of the antigen are memorized so we are prevented from getting the disease again
The concept of immune memory is due to the body’s ability to make antibodies against different pathogens
A vaccination against a virus can be made using either active, but weakened or attenuated virus, or using specific parts of the virus that are not active
Both attenuated whole virus and virus particles cannot actually cause an active infection, they mimic the presence of an active virus in order to cause an immune response, even though there are no real threats present
By getting a vaccination, one is exposing the body to the antigen required to produce antibodies specific to that virus, and acquire a memory of the virus, without experiencing illness