Ефективността на Purevax FeLV е проучена при няколко изпитвания в лабораторни условия, като котките са ваксинирани и заразени с FeLV.
In the field, efficacy has been studied in one main study of kittens aged eight weeks or older, in which the effects of Purevax FeLV were compared with those of another vaccine against FeLV.