Vaccines can mimic infections in several ways: - Live-attenuated vaccines use a weakened form of the virus or bacteria that can still replicate but does not cause illness. - Inactivated vaccines contain the virus or bacteria that has been killed so it cannot replicate at all. - Subunit, recombinant, and conjugate vaccines use specific pieces of the pathogen—like its protein, sugar, or capsid (a casing around the germ). - mRNA vaccines use a piece of the pathogen’s genetic material to instruct cells to produce a protein that triggers an immune response. - Vector vaccines use a different virus as a delivery system to carry the genetic material of the pathogen into cells.
