Rabies Vaccine Side Effects for Cats

Most feline rabies vaccine side effects are relatively minor, but some may be serious and even life threatening. Learn the most common side effects of the feline rabies vaccination, along with the more serious side effects, so you'll know what to watch out for after your cat has her rabies vaccination.

Common Rabies Vaccine Side Effects

Common rabies vaccine side effects are usually minor in their intensity, and the effects should wear off after a few days. They are caused by your cat's immune system responding to the vaccination and beginning to build an immunity. Here are some common side effects that may have an impact on your cat's life for a day or so after she receives the vaccination:

• Appetite loss
• Diarrhea
• Lethargy
• Low-grade fever
• Pain or swelling at the injection site
• Sneezing
• Vomiting

Serious Rabies Vaccine Side Effects

In some cases, your cat may develop more serious side effects than the minor ones listed above. More serious side effects can include:

• Anaphylactic Shock: Some cats have an allergic reaction to the vaccine. Symptoms to watch for include breathing problems, cold extremities, coma, diarrhea, facial swelling, seizures and vomiting. Immediate veterinary care is required to treat anaphylactic shock, which can be fatal if not treated promptly.
• Organ Damage: A protein in the rabies vaccine can sometimes damage a cat's liver, kidneys and nervous system. Organ damage can develop up to 45 days after a cat receives the vaccine. Watch out for loss of motor skills, seizures and tissue damage at the vaccination site.
• Vaccine-Associated Fibrosarcomas: About 1 percent of cats can develop cancerous tumors at the vaccination site. These tumors can develop anywhere from a few weeks after vaccination to years afterward. Fibrosarcomas do not usually spread, but they invade affected tissue deeply and can recur after surgical removal. Aggressive surgery and follow-up care by a veterinary oncologist is often required to resolve this condition.
• Vaccine-Induced Rabies: In extremely rare cases, cats have contracted rabies from live-virus vaccines. The cats began to show symptoms within 14 days of receiving the vaccination, and the symptoms included dementia, muscle stiffness and eventual paralysis. No cure exists for rabies.

If Your Cat Has a Serious Reaction

If you suspect your cat is having a serious reaction to her rabies vaccination, she needs to be seen either by your veterinarian or at an animal emergency hospital for urgent care. Unfortunately, not all serious reactions to rabies vaccination can be successfully treated, but supportive care can help your cat feel more comfortable.

Protect Your Cat against Vaccine Reactions

To protect your pet from developing a serious rabies vaccine side effect, ask your veterinarian to use only inactivated vaccines. Although they are not as long-lasting as live vaccines, inactivated vaccines cannot cause your cat to develop even a mild case of rabies, because the virus used is dead.

Another way to protect your cat against vaccine reactions is to ask your veterinarian whether an annual rabies vaccination is required by your local health department. Some jurisdictions accept a two- or three-year vaccination schedule, and your cat's risk of reaction is lessened if she doesn't have to have a vaccination every year.