No, vaccinating a pet while ill is not recommended. And yet I hear tell of this practice constantly. As in, “Yeah, my pet just went to the vet and she was treated for X, Y and Z. Oh, and, by the way, I also made sure she got her shots at the same time.”

Even some of my own clients, who’d I’d never make out for two-for-one types, often ask me to vaccinate their pets, “as long as they’re here.”

So that got me to thinking…do people not understand the concept of vaccines?

That’s why I thought it’d be a good idea to pen a post on the topic.

Here’s the skinny: Vaccines are administered with the expectation that the animal’s immune system will mount a safe and effective defense against the small amount of offending material injected. The resulting, controlled cellular response should—if everything goes well—protect the animal from future invasions by attacking microbes.

That’s the concept.

Now, consider a pet with an open, infected wound, a UTI (urinary tract infection), a URI (upper respiratory infection) or gastroenteritis (nonspecific vomiting and diarrhea). Should they be offered an immunological challenge at this specific moment?

I think not. Not for their own safety. And not when you consider the diminished potential for effective vaccination if the attempt is made while the animal’s immune system is otherwise occupied.

And yet it happens constantly in veterinary practices all over the US every day.

Why? Because…

1)    The vet thinks you or your pet is a safe bet for never showing up again. In these cases, vets may take the public health point of view, knowing that a vaccine may still be somewhat effective in many of these sickly pets. Why not vaccinate a trapped stray cat against rabies despite that pesky infection? (Indeed, I’ve been known to do it.)

2)    Your vet doesn’t know any better, thinks it’s a tiny risk, or hopes the vaccine may do the job despite the illness (and provides him/her extra income, to boot).

Vaccination is not something we should take lightly. (Unfortunately, some vets do, as do some human medical providers). Because every time we inject a specific quantity of biologically active material into an animal we run the risk of side effects.

Why would we ever risk doing so if the animal is sick (and tractable enough to be brought back in a couple weeks for a re-examination and vaccination)?

I dunno…but part of me thinks most pet owners are smart enough to understand the concept of a vaccine. Pet owners should be given the information necessary to comprehend the potential uselessness and unnecessary risk of a vaccine in the face of concurrent illness.

Got an itchy pet? Getting a steroid injection? Good luck with that rabies shot.