Duration of immunity in cats after vaccination or naturally acquired infection

The necessity for cats to be vaccinated annually against common pathogens h as been questioned because sarcomas have infrequently been reported at the injection site. However, with few exceptions, the duration of immunity indu ced by vaccination or infection is uncertain, and there may therefore be a risk associated with a decision not to revaccinate. This article reviews th e information available about the duration of immunity induced by vaccinati on or infection in cats, and reveals many shortcomings that make blanket re commendations impossible. Each vaccine must be considered individually.