Handling Potential Side Effects From Your Cat’s Non-Core Vaccinations

cats non core vaccine

Photo by Helena Lopes


Handling Potential Side Effects From Your Cat’s Non-Core Vaccinations

Vaccinations are one of the best ways to protect your cat from infections and viruses. Here in Australia, these are broken down into “core” and “non-core” vaccines. Core vaccinations are those considered essential for all cats, while non-core vaccines are optional and usually recommended based on a cat’s individual risk level, which can be impacted by where you live, whether your cat comes into regular contact with other animals and their overall health. If you opt for your cat to receive any non-core vaccines, it’s important to be aware of the vaccine side-effects they might experience and how to handle them if they do occur.

Why do side effects happen?

When your cat receives a vaccination, their immune system is stimulated to fight the infection. However, this can result in side effects. Normally, side effects are mild and show up quickly, lasting for around one to two days after your cat has had their injections.

Possible side effects to look out for

Non-core vaccinations are usually only given to cats that go outdoors or are especially at risk. The non-core vaccinations protect against Chlamydia, Feline Leukaemia, and Feline Immunodeficiency. Common side effects your cat may develop include:

• sensitivity at the injection site

• fever

• loss of appetite

• fatigue

Your cat could also develop more serious side effects, such as:

• weakness

• difficulty breathing

• vomiting

• diarrhoea


Cats can also develop uncommon side effects, such as:

• temporary limping

• sarcomas or tumours

Sarcomas at the injection site are fairly rare. Early detection can often result in the tumour being successfully removed, so it’s important to monitor your cat and make sure they recover from their vaccinations successfully.

If your cat’s side effects last for more than two days, make an appointment with your vet immediately.


Side effects from the Chlamydia vaccination

The Chlamydia bacteria can cause cats to suffer feline chlamydiosis, resulting in symptoms resembling conjunctivitis and an upper respiratory infection. Infections are generally spread through direct or close contact with infected cats.

Potential side effects of the vaccine may include:

• lethargy

• tenderness or hair loss at the injection site

• slight fever


Side effects from the Feline Leukaemia Virus vaccination

Feline Leukaemia attacks your cat’s immune system, making them more susceptible to other severe infections. It’s usually spread by sharing food and water bowls, mating, fighting, or mutual grooming with infected cats. Vaccination is considered only partially effective and is only administered to outdoor cats in high-risk areas, when the benefits of vaccinating outweigh the risks.

Potential vaccine side effects may include:

• tenderness or hair loss at the injection site

• lethargy

• slight fever

• injection site sarcomas

Side effects from the FIV vaccination

Feline Immunodeficiency Virus (FIV/Feline Immunodeficiency) is a blood-borne viral infection that affects your cat’s immune system. It’s usually spread by bite wounds or from an infected mother cat to her kittens. Around 15-30% of cats test positive for FIV in Australia each year.

Potential vaccine side effects may include:

• tenderness or hair loss at the injection site

• lethargy

• slight fever


What to do if you spot any side effects

Most cats will only experience mild vaccine side effects, if any, but in rare cases more serious side effects can occur. If your cat does experience serious side effects, the symptoms will usually happen almost immediately after the vaccination is administered. For this reason, it’s a good idea to stay at the vets for around 20 minutes after your cat has had their vaccinations, so you can monitor them for any reactions before going home.

Most side effects occur within 24 hours of the vaccination, so keep an eye on your cat and make sure they get plenty of rest. Any mild side effects will usually clear up within a few days, but they’re still worth raising with your vet, as these side effects can become more severe with subsequent vaccinations.


When to see your vet

If your cat’s mild side effects haven’t cleared up within two days, make an appointment with your vet. Or if your cat displays any serious side effects, you should contact your vet immediately, as this is a serious emergency.

Vaccinating your cat is vital to protect them and, with some careful planning, you’ll be ready to spot any side effects if they occur. The benefits of vaccinations do outweigh the risks, but it’s important to be prepared. You can find more information about vaccinations and caring for your cat on our petcare blog.


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