My cat is not eating and lethargic after vaccine. Is it a reaction?

Some poor appetite can be considered normal after vaccinations. Vaccines stimulate the immune system to help protect your pet from common diseases they could be exposed to. Vaccines can sometimes cause minor changes in appetite or behavior. Usually I tell clients some decrease in appetite and decreased activity can be normal for 24 hours but for any issues lasting more than 24 hours they should call me ASAP. Some of the major issues (although rare) associated with vaccine reactions are trouble breathing and anaphylactic shock. If you notice any trouble breathing, severe lethargy or swelling of the face or at the vaccine site you should contact your veterinarian as soon as possible. If the poor appetite is still an issue after 24 hours or If any other issues are going on contact your veterinarian ASAP.

No, this isn't normal behavior. While you can see a decrease in appetite and some lethargy, it's an unusual reaction to have a cat refusing to eat and drink, as well as not want to move. I would try to tempt her to eat by offering her some boiled white meat chicken (no bones) or soaking her food in tuna juice. If she still refuses to eat, then I would have her seen by a vet.

This sounds like a side effect of the vaccine, it's not super common but i'v seen a few cases already and this usually resolves within 48-72 hours. your vet could give her pain killers for a couple days if her condition seems to be really bad.

That is very unusual that he is not better and I think he should have a work up to try to figure out the cause. Your vet can run some bloodwork to rule out potential medical problems. Most cats are usually better within a few days after having a reaction to a vaccine and three weeks seems like a very long time. If your vet can't do a work-up then you should go to a different vet for a second opinion and work-up. So sorry that he is having this problem.

Thank you for submitting your question regarding Lily. Vaccines can result in lethargy. I would discuss this with her veterinarian at her next appointment. She may benefit from some pain medication in case she is uncomfortable after her shots. If she experiences vomiting after her vaccines, this is a sign of a reaction. Her veterinarian will need to know this information as well. Even if she is indoor only, vaccinations are necessary for her. I hope this information helps!

Poor Sansa! It is possible these clinical signs are related to the injections. Steroids can make pets have many side effects and upset stomach is one of them. The antibiotic is typically better tolerated but it can also make pets have a upset stomach as well. It’s also possible this is coincidental. I recommend to call the veterinarian and alert them as to what you were seeing. They may ask to see Sansa to check her for a fever or other evidence of illness. Make sure Sansa eats and drinks today. You may try offering her some palatable canned cat food with some extra water added. If she continues to be a lethargic or not eating or drinking for 24 hours, she should be seen by the veterinarian as dehydration can settle in quickly. I hope she starts feeling better quickly and please feel free to post any additional questions.

I am so sorry that your cat Milo is ill following vaccines. These are classic signs for a vaccine reaction, and therefore I recommend having him seen by your vet right away. If you vet is currently not open, then I would consider taking him to your ER vet to make sure he is stable and ok. He will likely get medications (antihistamine +/- steroids) to help combat the reaction. I do hope that your pet Milo is able to make a full and speedy recovery. I would notify your vet about this as soon as you can so that precautions can be taken next year when he is due for his vaccine boosters to help prevent this from happening again. Best of luck and take care!