Vaccinations are a safe and essential part of keeping your cat healthy. Like any medical treatment, however, they can occasionally cause mild side effects. These reactions are usually short-lived and resolve on their own—but it’s good to know what to expect.
Common, Mild Side Effects
Most cats experience little to no reaction. If they do, the most common side effects include:
- Mild fever
- Temporary tiredness or reduced appetite
- A small, firm lump at the injection site
- Slight soreness or sensitivity at the injection area
These effects typically appear within a few hours and resolve within 24–48 hours without treatment.
Less Common Reactions
In rare cases, a cat may experience:
- Vomiting or diarrhoea
- Swelling of the face or paws
- Hives or itching
- Difficulty breathing
- Collapse
These are signs of an allergic reaction and require immediate veterinary attention. While serious reactions are extremely rare, we always recommend monitoring your cat closely after any vaccination.