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Cat sick post-vaccine: fever, vomiting, tired, won't eat. What now?

Updated on September 23rd, 2025

Pet's info: Cat | Maine Coon | Female | unspayed | 6 months and 19 days old

Hello I took my cat to the vet yesterday for a vaccineand the vet said she might have a fever and vomit so prescribed a Medicine and when I got home I gave to her and after a little while she threw up, she looked so tired and won't move and then after a few hours I gave her some tuna and she threw it up so I didn't give her any other food then she couldn't sleep well at night, and today I gave her some water and some food she drank a bit but she refused to eat and she has a slight fever, help :/

2 Answers

Most Helpful Answer

Answered By Daniel Fonza, DVM

Veterinarian

Published on October 20th, 2017

Hi there and thank you for using Pet Coach to address your concern. My suggestion would be to have the veterinarian who administer the vaccination recheck Suzie. Sometimes vaccination reactions can cause the symptoms you are seeing so it would be advisable to have her looked at so the reaction does not progress. Your vet can then administer medications to help treat a possible reaction such as benadryl and a steroid injection. I hope this helps and I hope Suzie gets better! Please let me know if you have any other questions or concerns. I am also available for consult if needed.

1Pet Parents found this answer helpful

Related Answers from Veterinarians

Answered By Laura Johnson VMD
Veterinarian
Published on November 6th, 2017
Hi, thanks for using Petco Pet Education Center, formerly Petcoach! Poor Bandit!

I don't think the fact that the vaccines were given at the same spot is why Bandit is sick. She definitely could be suffering from a vaccine reaction, which has nothing to do with where the vaccines were given.

Since Bandit has been sick for 10 days I think it is very important to have her seen by your Vet. Cats can not go a long time with a poor appetite or they can become sicker (fatty liver). She may have a fever which is why she is lethargic and not eating well. If the Vet thinks she is having a vaccine reactions steroids are usually given as an infections and possible sent home as well. If the Vet feels something else is going on then they may do blood work or X-rays.

I hope this helps and I wish Bandit a speedy recovery!
1Pet Parents found this answer helpful

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