Fourteenth century physicians didn't know what caused the plague, but they knew it was contagious. As a result they wore an early kind of bioprotective suit which included a large beaked head piece. The beak of the head piece, which made them look like large birds, was filled with vinegar, sweet oils and other strong smelling compounds to counteract the stench of the dead and dying plague victims.
Bubonic plague has a vaccine.
It lasts for about 6 months. Currently, plague vaccine is not available in the United States. A new vaccine is being worked on and could be licensed later this year. Travelers to plague infested areas should take prophylaxic antibiotics. The preferred antibiotic for prophylaxis is tetracycline or doxycycline, and for children 8 or less, sulfonamides.