Vaccine Side Effects in Dogs and Cats: a real risk or nothing to fear?

Vaccinating your dog or cat is one of the cornerstones of preventative health. It stops them suffering from diseases that can be fatal. Vaccine side effects are one of the hot topics at the moment in both human and pet health.

What are the real risks of vaccination?

vaccine side effects in puppies

This question was sent in by an owner whose dog had got his vaccination a day previously and he was then shaking, he wasn't very well and they’re wondering if that’s normal and if that’s something that can be expected.

What are vaccines?

Well, let's start off with thinking about what vaccines actually do. They're essentially a way of tricking the body into thinking that it is suffering from an infection, so that it can then eliminate a true infection at the very early stages, when it's just starting, before it can then start to affect the rest of the body. A vaccine does this by the administration of either a dead virus or bacteria, or a live version that has actually been modified so that it can't fully replicate, or it can't cause the full blown disease that an unmodified (naturally occurring) bacteria or virus would do.

Vaccine side effects

As a result, we’ll often actually see mild side effects, which are just signs that the body is essentially fighting a mild infection. I know personally that after I have a tetanus vaccine, my arm really aches for a couple of days and I feel pretty rough for the next 24 - 48 hours. And that's pretty similar to what we can expect with our pets in some cases.

Common side effects

So fever, lethargy, inappetence, weakness, stiffness or even tenderness and sometimes local swelling at the area of an injection and vaccination is not all that uncommon and that can absolutely manifest as shaking or trembling in some dogs. These side effects are more common in younger animals in my experience, and most dogs actually don't get any kind of problem or they'll just be a little bit quiet for a day.

If a dog does experience these side effects or a cat experiences these side effects, they typically resolve after about 24 to 48 hours. They don't need any specific treatment, just a bit of TLC at home and they're soon right as rain. We've got to remember they’re protected from a potentially fatal disease, so we've got to get our priorities right from that point of view.

serious side effects

That's not to say that side effects or serious side effects are completely non-existent. There are risks of very rare but more serious side effects and that can be an anaphylactic reaction that can result in breathing difficulties, collapse and ultimately death. We can get vomiting and diarrhea, we can get generalized swelling of the face and neck, and we can also get something called injection site sarcomas, typically in cats. These are rare, but are tumors that develop at the site of repeated injections. So they're not necessarily vaccine related. I think it was first thought that they were vaccine related, but they are injection site sarcomas. So it can be injections for other reasons and they cause these really nasty aggressive tumors.

So those are the serious side effects, but we don't want to over-stress them, because they are very uncommon.

Side effect treatment

For more mild side effects, a vet might give some anti-inflammatory medication at the time of vaccine if you know that your pet has had one of these side effects in the past. Obviously, if they've had more serious side effects, if they'd been very unwell, if they've had a suspect anaphylactic reaction, if they’re vomiting, have diarrhea, if they've collapsed, then we really need to be careful with giving follow-up vaccines. So there are different types of vaccination but we also need to weigh up the benefits against the risks to an individual.

So if it's felt that there are going to be serious health risks as a result of vaccination then we need to question if it’s really essential in that individual.

Another tool we have is titer testing, something I have covered in detail in my post about titer testing vs vaccination.

The above is a transcript taken from “The Dr Alex Answers Show”.

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