plague vaccine, an active immunizing agent prepared with killed plague bacilli. ▪ INDICATIONS: It is prescribed for immunization against plague after probable exposure or as protection for travelers in endemic areas, such as Southeast Asia. ▪ CONTRAINDICATIONS: Immunosuppression or acute infection prohibits its use. ▪ ADVERSE EFFECTS: Among the most serious adverse effects are allergic reactions, inflammation at the site of injection, headache, and malaise.