Allergic Reaction to Vaccines Average Cost

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What are Allergic Reaction to Vaccines?

A vaccine is the modified form of an organism, containing the antigens for a disease, but are not infectious. When the agent is injected, the immune system responds by creating specialized antibodies for that specific infectious organism. The purpose of the vaccine is to stimulate the immune response to make specific cells to keep circulating the body. Therefore, when the feline is exposed to the virus or bacteria, the immune system is prepared to fight it. Sometimes the immune system overreacts, causing an allergic reaction to vaccines in the feline. Symptoms of an allergic reaction can be mild, moderate or severe, and vary depending on the type of vaccination received. 

It is normal for a cat to experience a few mild side effects after receiving her vaccines, such as local swelling or pain at the injection site, but if hives appear, your cat could have an allergic reaction to a vaccine. Your cat’s immune system plays a vital role in protecting the body from infectious ailments to keep her healthy. Making antibodies against parasites, microbes, bacteria and viruses is one of the most important functions of the immune system. Unfortunately, this complex system cannot make specialized cells to fight every disease that invades the body, so vaccines are given to help the immune system prepare. 

Symptoms of Allergic Reaction to Vaccines in Cats

An allergic reaction to vaccines in cats can be mild, moderate or severe and can appear within a few hours to several days after the vaccination was given. Severe reactions are usually associated with killed varieties of vaccines such as feline leukemia virus and rabies. 

Mild Vaccine Reaction

  • Fever
  • Loss of appetite 
  • Swelling, redness or pain at the injection site
  • Temporary lameness 
  • Temporary joint soreness 
  • Sneezing lasting roughly 4-7 days
  • Low activity levels 

Moderate Vaccine Reaction 

  • Urticaria (hives) 
  • Pruritus (itchy skin)
  • Swelling of the neck, eyes and/or lips
  • Redness 
  • Fever

Severe Vaccine Reaction: 

  • Very sudden allergic reaction (less than 24 hours) 
  • Breathing difficulties 
  • Diarrhea
  • Vomiting 
  • Decreased blood pressure 
  • Pale mucous membranes
  • Cold extremities 
  • Cardiac arrest 
  • Shock 
  • Seizures
  • Collapse 
  • Death 

Causes of Allergic Reaction to Vaccines in Cats

An allergic reaction to vaccines in cats is caused by an over-reactive response to the immune system. The antigen within the vaccine is used to stimulate the cat’s immune system to create specialized antibodies against the virus, bacteria or disease. However, the nature of some feline immune systems are hypersensitive and overreact to the introduced antigen. Common feline vaccinations that have been known to cause an allergic reaction in cats include vaccines against: 

  • Feline Panleukopenia
  • Giardiasis
  • Bordetellosis
  • Feline Immunodeficiency Virus
  • Feline Infectious Peritonitis
  • Chlamydiosis
  • Feline Leukemia Virus
  • Rabies
  • Feline Herpesvirus and Feline Calicivirus

Diagnosis of Allergic Reaction to Vaccines in Cats

Allergic reactions can be caused by a variety of elements in your cat’s environment, causing similar symptoms of a vaccine allergic reaction. Therefore, the veterinarian may want to perform a differential diagnostic exam such as an intradermal allergy test to rule out other causes. 

To diagnose an allergic response to vaccines specifically, the veterinarian will review your feline’s current vaccination history, paying close attention to which vaccines were scheduled to be administered. The vaccination history will reveal which vaccines were administered, the date of administration, and location. The doctor can then pair the medical record with your cat’s current condition to diagnose the allergic reaction to a vaccine. 

Treatment of Allergic Reaction to Vaccines in Cats

Mild to moderate cases of an allergic reaction can be symptomatically treated with anti-inflammatory drugs such as a corticosteroid. A feline with a mild or moderate allergic reaction to vaccines should return to normal health within a week. However, moderate allergic reactions can worsen over time and become severe, so the feline will need to be monitored for the duration of the allergic response. 

Cats with a severe allergic reaction to vaccines need to be rushed to the veterinary emergency clinic right away. The doctor will begin administering life support to the feline including intravenous fluids and oxygen. The feline’s airways will be monitored to ensure they do not close at any time. Felines that are stabilized will likely survive anaphylaxis, but will require hospitalization for a couple days after anaphylaxis shock before returning home.

Recovery of Allergic Reaction to Vaccines in Cats

Allergic reaction to vaccines in cats is very rare, but if your feline has a history of vaccine hypersensitivity talk to your veterinarian. The next time the vaccine is needed, the veterinarian may include an antihistamine to prevent an adverse reaction or eliminate the vaccine from your cat’s vaccination schedule altogether. It is important to discuss vaccinations with your veterinarian to fully understand the risks and benefits that come from vaccines. In most cases, the benefits of vaccinating your cat outweigh the risks, which are small by comparison. 

Allergic Reaction to Vaccines Questions and Advice from Veterinary Professionals

3 Months
Fair condition
0 found helpful
Fair condition

I adopted a kitten and got his first shots.. He’s reacted bad, he usually looks for people to carry him and make him sleep like a baby but I know he hasn’t slept and doesn’t want to eat, he’s always laying down and if you pet him, he cries..Is that an allergic reaction or it’s just a side effect?

Dr. Callum Turner, DVM
1184 Recommendations
Some cats (and dogs) have a reaction to vaccines which may cause strange behaviour, vomiting, lethargy, loss of appetite among other side effects; if rabies was part of the vaccination then this affects cats (and dogs) more than other vaccines. If you are noticing a severe reaction and if Arco isn’t eating or drinking, pop back into your Veterinarian to be on the safe side. Regards Dr Callum Turner DVM

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short hair
5 Years
Serious condition
0 found helpful
Serious condition

Hi, my cat had her vaccinations as a kitten then nothing until she was four. I decided to get the vaccinations again, after the booster she ended up on a drip for 24 hours and was very ill. She was also very distressed having to have several blood tests. At the same time she had been given advocate which was out of date (vet advised that this was safe), was it?? I reluctantly got the second vaccine, she was a little ofc colour but seemed ok. It has been a year and it's now time for vaccinations. Should i risk another reaction??? I have read vets follow manufacturer's advice for yearly vaccinations but they only need them every 3 years??? Any advice would be much appreciated. I have two cats who are brother and sister and there was only two in the litter, i wonder if their immune systems are better due to this??

Dr. Callum Turner, DVM
1184 Recommendations
There are mixed opinions on whether or not cats or dogs require annual vaccinations, I recommend following manufacturer’s recommendations since if there are any issues I can always refer to the prescribing information but owners should be informed and be allowed to make their own decisions. Below, there is a link to a page on feline vaccines from Cornell Veterinary School which covers this topic under the heading ‘Does my adult cat need to be vaccinated every year?’. Regards Dr Callum Turner DVM

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