I just received my vet reminder that my kitten needs his FVCRP booster. He's already had a uri from the shelter (and given it to my other cat). Since the FVCRP is supposed to prevent uris, do I need to immunize him from something he already has? When my other cat completed his series (which proved to be somewhat ineffective since he developed a uri), he was very lethargic and not feeling so great so I would like to bypass the shots for my kitten if at all possible.