Like humans, some cats have side effects after animal vaccinations. They may be grumpy, listless and a bit out of sorts for a while. While you don't expect your cat to have any serious problems, you'll keep an eye on them anyway just to make sure they're OK.
You may, however, start to worry if your cat shows unusual physical symptoms in the first few days after getting a shot. For example, if your cat starts to limp, but it hasn't done anything to injure its leg, you may worry that the vaccination is the problem. Why is your cat limping now and is this limp something to worry about?
Vaccination Site Limps
If your vet injected your pet in one of its legs or feet, then it may develop a limp for a short time. This limp may not be obvious for the first few hours or even the day of vaccination; it may develop the day after. Typically, this kind of limp is simply down to soreness and stiffness. The vaccination site will be tender for a while, and your cat's leg may simply be a bit painful to walk on. Its movement can be a bit restricted, hence the limp.
If your cat is limping on the leg or foot where the vaccination was given, then you probably have nothing to worry about. The limp should clear up on its own once the soreness on the injection site subsides.
Vaccination Reaction Limps
Some cats have reactions to vaccinations that mimic the symptoms of the condition they were vaccinated against. This happens as their systems adapt to the medication so that they can create antibodies to prevent future infections.
If your cat has been immunised against Feline Calicivirus (FCV), then limping can be a short-term side effect. Cats that catch FCV often limp, so some cats get a limp after vaccination. Typically, this kind of limp doesn't just happen on one leg but may switch between different legs at different times. Again, this should clear up on its own after a few days.
Cats shouldn't have a long-term limp after a vaccination. If your cat doesn't stop limping after a couple of days, or if it shows other signs of being unwell, then call your vet for advice. While the limp isn't likely to be serious, your vet may want to check your pet over just to make sure.