StroVac® vaccination (formerly Karenovac®) is a method for the prevention and treatment of recurrent bacterial urinary tract infections. Indications for the use of StroVac vaccine include recurrent (repeating) bacterial urinary tract infections. StroVac contains killed types of bacteria that most commonly cause urinary tract infections. The basic immunization with StroVac is administered three times at intervals of approximately 2 weeks. It provides protection for about twelve months. The so-called Booster-StroVac is used to renew the immune response approximately one year later (revaccination).