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.