I suppose it could be linked by a drain on the immune system... if your body 
is trying to fight one thing, and then you add in those cats, then your 
immune system is working overtime.  Or, if the shots are helping your immune 
system deal with the cats then it's freed up to tackle other things.

One thing that I've found in my dairy exploits is that not all dairy is 
created equally.  If I break down and eat pizza at Pizza Hut (shame on me!), 
my symptoms aren't as bad as that of Domino's Pizza or the other chains. 
I'm not sure what the difference would be - mozzarella cheese on both of 
them.  Most likely a combination of parmesan and other things could throw it 
off.  So, my point on this is that I think some dairy derivatives may be 
"different" somehow thuse causing different reactions even though they say 
"dairy" or "milk" in the ingredients.  I have no idea why.

I aplogize for my Sunday babble!

Jenifer