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Why did my pet get a fever from their second vaccine, not the first?

Updated on September 23rd, 2025

Pet's info: Cat | Himalayan | Female | unspayed | 2 months and 24 days old | 6.6 lbs

Hi, I have a very strange question! First time she had her shot, the other young vet told me he had this expensive vaccine that will not coz her to have fever & she didn't. But Now this second one caused her the fever. Was that shot a fraud?

1 Answer

Most Helpful Answer

Megan, DVM, CVA

Answered By Megan, DVM, CVA

Veterinarian

Published on December 3rd, 2017

Not necessarily. Some animals will have a reaction to the vaccine after being previously exposed to it. So since she already had the first vaccine, her body had a reaction to the second one. When she gets her third one, I would give her some Benadryl about 10-20 minutes beforehand. See the article for more info on Benadryl. I hope this helps!

https://www.petcoach.co/canigive/cat/benadryl/
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