Here's something I've been puzzling over for a time.

When the parents of our two cats had a URI about a year and a half ago,
after we gave them their innoculation series, it...well, it just  went
away. Granted, though, that they were at this point five or six months of
age.

Now here's what's up - something we heard from our vet back in November
was that this is generally not a good idea, especially with weeks-old
kittens, for fear of an adverse reaction - she didn't infer as to what
that could be though.

At any rate, largely out of curiousity, if one innoculates a cat amidst a
URI, what risks are they taking with the cat?