Attenuated vaccine

An attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable (or 'live'). Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by 'killing' the virus (inactivated vaccine). An attenuated vaccine is a vaccine created by reducing the virulence of a pathogen, but still keeping it viable (or 'live'). Attenuation takes an infectious agent and alters it so that it becomes harmless or less virulent. These vaccines contrast to those produced by 'killing' the virus (inactivated vaccine).