Vaccines: Mechanism of Protection
This video presents the same text shown beside it, spoken and on screen. It adds nothing the text does not say.
State
A vaccine builds immunity by exposing the immune system to a live-attenuated, killed, or subunit form of a virus, without causing full disease.
Show
A killed-virus vaccine cannot cause infection, while a live-attenuated one replicates poorly, both training the immune system to recognize the virus.
Watch for
A live-attenuated vaccine carries a small risk of reverting to a disease-causing form, unlike a killed-virus vaccine.