Plague vaccine is a vaccine used against Yersinia pestis.Killed bacteria have been used since 1890 but are less effective against pneumonic plague so that recently live vaccines of an attenuated type have been developed for this situation.
A plague vaccine is used for an induction of active specific immunity in a susceptible organism to plague by means of administration an antigenic material (a vaccine) via a variety of routes to people at risk of contracting any clinical form of plague. This method is known as plague immunization. There is strong evidence for the efficacy of administration of some plague vaccines in preventing or ameliorating the effects of a variety of clinical forms of infection by Yersinia pestis. Plague immunization also encompasses incurring state of passive specific immunity to plague in a susceptible organism after administration of a plague serum or plague immunoglobulin in people with an immediate risk of developing the disease