Revaccination after vaccine reaction in kitten

I am fostering a litter of 9 week kittens. Supposedly they were all vaccinated at animal control at 6 weeks. One of the kittens had a significant vaccine reaction after his booster shot at 9 weeks. Within 15 minutes he was vomiting repeatedly (about 10 times in 30 minutes!), itching, and having significant lethargy. Fortunately after some fluids and rest he recovered quite well. He is now back to his frisky, adorable self.

If he were an older kitty, I would be very hesitant ever vaccinating him again. However, since he is a kitten with virtually no immunity, would it be worth completing his vaccination series or is this too risky after this type of reaction?

I would keep the kitten isolated from all new cats until 14 weeks of age, then administer a single vaccine, with an antihistamine on board, and keep the kitten at the vet for supervision for the rest of the day. If the kitten had no or very little reaction, then booster 3 weeks later, and give rabies 3 weeks after that. This would guarrantee that the kitten was old enough to get immunity with a single vaccination if necessary. I would then do titers for the rest of the kittens life.

Well, with human vaccies sometimes you have a reaction because they're using an egg base; so instead the doctor uses a different version without any egg in it. If the kitten was allergic to something in the vaccine, then maybe the vet could find a different version of the vaccine that he wouldn't be allergic to... if it was an allergic reaction, anyhow.

Baby Girl was quite tired after her own first set of vaccinations and ate very little the first day afterwards; but the second series didn't slow her down at all. Apparently after she'd built up an initial immunity, it was easier for her to tolerate the second set.

Blossom just spent last night at the vet's due to a reaction to her 1st annual vaccination. She was given a steroid/anti-inflamatory to bring down her temp. In future she is not to get the leukemia componant of the vaccination & have an anti-inflamatory before the next vac. next year. When she was having her baby shots she had a reaction to the 2nd vac.

My youngest had a similar issue with shots. She was real listless for a day or two (but not near as sick) and same thing after round two -- we never went for anything more as we were too afraid for her. She was sick and weak when we rescued her in the first place.

I would be quite hesitant to re-vaccinate this little one, but if you choose to do so, be quite sure the vaccine is accompanied by an antihistamine.

Thank you all for the input. Unfortunately, I do not know of which component of the vaccine (Fel-O-Vax IV) he was allergic too. I don't think this is comparable to the egg allergy in humans and that there is an egg-free form for kitties.

I have vaccinated many, many kitties before and I know that poor appetite, lethargy, fevers, etc are common. I have experienced several sick, sore kitties in the past after a vaccine. However, I have never vaccinated one with such am immediate and severe allergic type reaction. If we vaccinate at all, it certainly seems reasonable to do with antihistamine on board, steroids near by, only one vaccine (or component of a vaccine), and with the presense of a vet for the day. Thanks again!