A live virus vaccine contains a live, weakened (attenuated) virus that aids in the production of an immune response without causing you to experience symptoms of the disease it is supposed to prevent. Your immune system is "taught" by the weakened virus to identify the disease-causing pathogen and launch a pathogen-specific attack. Many of these vaccines have lifetime immunity after just one or two doses.
Trisha Penuli
Journal of Preventive Medicine received 226 citations as per google scholar report