Some animals are more sensitive than others. I adopted a puppy that I wanted to split vaccines - my vet apparently didn't and gave all vac's - even though I said no. His immune system couldn't handle it and caused a demodex flare up.Is it caused by them giving the Rabies and FVRCP Distemper vaccines together? I was thinking of spacing them out next time my cats get them, but it is hard to take them to the vet more than once, they are still quite feral with strangers.