Translate This Blog

Friday, May 8, 2009

Vaccinating Sick Pets

Here's a common scenario that many vets face. A pet comes in for an illness. Sometimes it may be for something relatively minor like a skin or ear infection. But more likely it will be a potentially serious problem such as profuse vomiting, not eating, being extremely lethargic, and so on. Chances are good that this problem has been going on for a while, and it seems that these cases happen in pets that rarely get veterinary care. So there we are with a pet that might have a very serious illness when the next question comes up.

"Hey, doc. While we're here could you give him his shots?"

Sometimes I can't completely understand some people. Their pet is sick and I'm talking about having to do a battery of tests to determine if it may be life-threatening. Yet they seem more concerned about the fact that they haven't brought this pet to a vet for vaccinations in a few years. These people seem to find the lapsed vaccines a greater concern than the illness that just happened to motivate them to come through our doors. So let's have a little lesson in immunology.

The immune system in a living creature is a truly remarkable and complex thing. When an animal or person becomes sick there is a cascade of events and chemicals within the body as the organism tries to correct or heal the illness. Antibodies may be produced, inflammatory mediators are released, white blood cells are released from the bone marrow, blood vessels become leaky, and many other things can happen. All of this is a normal response whether it's due to an injury or infectious disease. However, this normal response can lead to adverse effects on the body depending on the severity of the response. The immune system is also not limitless. There are only so many white blood cells that can be produced at one time. There are only so many resources the body has. And there is only so much a body can take at one time.

This is where vaccines come into the picture. When we give immunizations, we are stimulating the immune system to have many of the above effects. However, if the immune system is already "busy" trying to fight off another problem, it may not respond properly to the vaccine. This might mean that the body doesn't develop proper immunity and the shot ends up being worthless. Or, the stress of this secondary response on the immune system may make it harder to fight off the primary infection.

Put simply, we don't vaccinate seriously ill pets or people. It's simply not a good idea. A minor, local illness (such as an ear infection or small wound) isn't a big deal and we can still immunize. But vets aren't going to do this if there is a serious or wide-spread problem.

So the next time you take your pet to the vet for an illness, please don't ask them to vaccinate him or her until the problem is corrected. And make sure to visit your vet regularly so that you don't get behind on vaccines and physical exams to put you in this situation.


  1. Until entering into a molecular bio/ immunology based lab in grad school, I didn't realize it was a bad idea either.

    I think most people who do not regular vaccinate their pet are simply concerned about the office visit fees associated with coming back for a second visit. Not that they aren't worried about their pet, or they wouldn't have asked about the inoculations period, but more they aren't going to do it if you require the second trip.

    A good vet would do as you mentioned and not take the people's money and put the animals immune system under undue stress while they are seriously ill... Bad vets don't bat an eye and shoot the pet up anyway.

    This is of course, in my completely un-professional opinion. Great topic, and I wish more people were aware!

  2. I agree that the people don't think about what can happen or realize the problems. That's part of the reason for my blog, so that more people will be educated about it. But unfortunately it seems that most of the people that end up in this situation haven't kept up on their pets' vaccinations. I try to think the best of people, but in this business you have to fight becoming a bit cynical.

  3. I get so tired of that. People only bring their dog in whent it's sick and then want vaccines while they are there. Obviously they didn't care that much about the vaccines before-they just want to not spend an extra exam fee if they don't have to. I usually tell we can give the vaccines if everything is going well on a recheck-helps get them back in for the recheck sometimes.

  4. That's something that people with small children that they take for shots every 3 months would know, but I bet parents of much older children or people without children wouldn't necessarily know that. Especially if they aren't in the medical field.

    It's funny, In March I took my daughter in for her 4 year old well-child check-up, and they wanted to give her five shots! I told them they could give her three. (They gave me the option.) This week I got a call from the preschool she will be starting in the Fall. She has to have the rest of her shots by next week if I want her to be able to go. I called the doctor's office and asked them if I was going to have to do another co-pay. I guess I can relate with the pet owner that wants to kill two birds with one stone (it does get expensive), but I wouldn't want to do it to the detriment of my loved-one's health. Now my poor daughter has the terror of becoming a human pin-cushion again, but I still think it was better to space out her shots.

    Was that terribly off-base? Did anything that I just said relate to this conversation in any meaningful way? Anyway, that was a good and informative post.

  5. No, you're not off base, Mary, and what you say makes sense. The reason for my post was that I realize many people don't understand why we can't vaccinate sick pets and I wanted to explain it. But your analogy fits.

    Personally, I have no problem with giving or receiving five vaccines at once. It doesn't significantly increase the risk of having a reaction, and I'd rather just get it all done in one fell swoop.

  6. HI Dr. Bern, this thread is so old... not sure if you've covered this in another post, but do you consider ringworm to be an immune system stressor that would warrant waiting on FVRCP? I run a nonprofit kitten rescue, and it's a RARE occasion a rescued kitten doesn't come in with *SOMETHING* wrong with them. It's usually Coccidia, URI, Ringworm or some sort of wound. I wouldn't vaccinate on intake with the first two issues for sure, but I'm wondering your opinon on vaccinating with active ringworm? Thanks! Can't wait to read your blog - I <3 pet people.

    1. Actually, I haven't talked about this elsewhere. There is certainly a school of thought that ringworm is more likely to happen in a pet with a compromised immune system. However, I've seen it in apparently completely healthy pets. If ringworm was the only disorder and the pet was otherwise in good condition I would personally still vaccinate. If there were other disorders, I would possibly postpone it, depending on what else was going on. It's also important to distinguish between local and systemic illness. A minor laceration, ear infection, or intestinal parasites wouldn't stop me from vaccinating. A full-blown respiratory infection would. In your particular case, you're absolutely right that it's unusual for you to have a 100% healthy kitten. If you were my client, I'd look at the kitten's overall health and temperature. If there was a fever or the pet seemed systemically ill, I'd wait to vaccinate until the illness resolved. If it was something like roundworms, coccidia, ear mites, etc., I would go ahead and vaccinate. But I wouldn't be opposed to a vet who didn't want to vaccinate during an active ringworm infection or similar problems, as they do have a valid point.

  7. It wasn't apparent at the time, but when my dog was vaccinated for CIV (bivalent vaccine), she had picked up kennel cough 6 days earlier. It was a a mild case; she had some intermittent hacking 4 days after the shot. While the hacking got more frequent the next day, she did it only once the following day. Would this have been serious enough to affect the CIV vaccination?

    1. Unlikely. If it was mild I would have likely vaccinated a patient of mine like this.


Thank you for making a comment on my blog! Please be aware that due to spammers putting links in their comments I moderate every comment. ANY COMMENTS WITH AN EXTERNAL LINK NOT RELATED TO THE TOPIC WILL LIKELY BE DELETED AND MARKED AS SPAM. If you are someone who is posting links to increase the traffic to another website, save me and you the time and hassle and simply don't comment. To everyone else.....comment away! I really do enjoy hearing from readers!