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Navigating Side Effects From Your Cat’s Core Vaccinations

Making sure your cat receives their core vaccinations is vital to help them fend off potentially-fatal diseases. However, since vaccinations stimulate your cat’s immune system, this may trigger an allergic response that presents as side effects. Although side effects are rare, learning what to look out for will help you know how to react if they do appear, and puts you in the best position to keep your cat safe and healthy.

Vaccinations your cat should receive

Your cat’s vaccinations are split into two categories, core and non-core. Core covers the minimum required vaccinations to protect your cat from serious illnesses and non-core are optional for extra protection. In Australia, cat owners are advised to vaccinate their cats for contagious, and potentially life-threatening, diseases such as rhinotracheitis (herpesvirus), calicivirus and feline enteritis (parvovirus). One vaccine, F3, protects your cat against all three diseases. If your cat is an indoor cat that doesn’t come into contact with other animals, you may wish to discuss with your vet which vaccinations are advised.

Why do side effects happen?

Vaccination side effects are rare and, if they do occur, should only be mild. However, some side effects can occur because the vaccination stimulates your cat’s immune system. If side effects do occur, they should appear soon after your cat has been vaccinated, but if their symptoms do not clear up after 24-48 hours, or they get worse, call your vet.

Possible side effects to look out for

Common vaccination side effects include:

• tenderness or sensitivity where they’ve been injected

• loss of fur at the injection site

• fever

• fatigue

• loss of appetite.

Very rarely, more serious reactions can occur, such as:

• incoordination

• difficulty breathing

• vomiting and diarrhoea

• severe anaphylaxis, with symptoms including hives, collapsing, vomiting, or prolonged fever.

Your vet may want to check your cat shortly after their injections to make sure no side effects are showing.

How to look after your cat post-vaccination

Like humans, cats react in different ways when receiving vaccines, some behaving as they normally would and others becoming more clingy. This is why it’s perfectly normal for cats to want to be left alone or to lose their appetite within the first 24 hours after their vaccinations. To ensure your cat is kept comfortable, you can:

• keep them warm and quiet, with their favourite blanket or comforting items

• ensure they have access to clean, fresh water and food

• make sure the injection side isn’t irritated and avoid patting it

• check on them regularly to make sure they aren’t showing side effects

What to do if you spot any side effects

Serious side effects will often occur soon after your cat has had their vaccinations, so be sure to keep an eye on them for the 24 hours following their injections. Most reactions and side effects will clear up within a day. If you spot any side effects, even mild reactions, make a note of them and be sure to let your vet know. Side effects can often become more serious with subsequent injections, so it’s important your vet is aware of how your cat has reacted to their vaccines.

When to see your vet

If your cat is experiencing mild side effects after their vaccinations, and they haven’t recovered after two days, it’s time to make an appointment with your vet. In the event your cat is showing signs of serious side effects, contact your vet immediately as this is an emergency. Knowing what potential reactions to expect should help you feel confident about taking your cat for their core vaccinations, so you’ll be ready to handle any side effects that may occur. You can find more information about vaccinations and caring for your cat on our petcare blog.

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