Hi, I’m Dr. Karyn! Read my introduction to learn more about me and meet my five funny cats: Clutch, Cyril, Alex, Zelda, and Zazzles.
You might assume that as a vet, I have a pretty strong stance on vaccinations, but like you, I want to make sure the choices I make are based on facts and science, and are right for my cats, and my situation .
In veterinary practice, our recommendations need to be consistent with the manufacturer’s guidelines; it’s simply not practical to have many different options for many different situations. With that in mind, there are three messages I want all cat owners to take home:
- Vaccination absolutely saves lives.
- YOU have the final say on how often and what vaccinations your cats receive (except for rabies).
- Your decisions about vaccination should be based on FACT, not FEAR.
I am often asked “Are vaccinations safe?” and the honest answer is that introducing a foreign agent into the body to elicit an immune response is not 100% safe, but it is safer than leaving your pet exposed to the risks of developing deadly virus. So you might want to know:
Do I vaccinate my cats? Yes.
Am I strictly following the manufacturer’s guidelines? Not completely.
Do I know that I am in danger by deviating from those rules? Yes, but I base my decision on the risk factors for my particular situation.
If you want to know what influences my decisions about vaccinating my cats, we’ll have to get some of the nitty-gritty out of the way. Trust me, you’ll walk away feeling more confident about making the right choices for your cats with a little knowledge under your belt.
How Vaccination Works – In short
The practice of exposing humans, and later, animals, to a small dose of an infectious agent to trigger an immune response dates back to at least the mid-15th century, possibly even earlier. then. When Smallpox was busy wiping out hundreds of millions of people around the world, a process called variolation appeared, in which a small amount of fluid from a smallpox lesion was injected into a healthy person. It was a risky procedure because the chances of developing a severe case of smallpox were very high, but it began to prove that a small dose of the virus could create enough of an immune response to make the patient immune.
But until a man named Dr Edward Jenner (in fact, you can’t go anywhere without hearing about a Jenner these days!) discovered that the same immune response could be achieved by using cowpox – a related but safer poxvirus.
How does this work?
When a virus enters the body, it triggers the immune system to release pathogen-fighting cells such as neutrophils, monocytes, and lymphocytes (T cells and B cells). After a while, the body begins to produce lymphocytes that are more specifically adapted to fight viral particles, resulting in a faster, stronger attack.
If the virus is successfully killed, the bone marrow continues to produce cells that can target the specific virus, called memory B and T cells. These memory cells can last for months, years, or a lifetime, depending on the virus and the individual.
The problem with relying on our natural immune response to a virus is that it’s a game of chance. We develop natural immunity only if we survive, and we can have long-term or permanent health consequences from infection.
This is where vaccination comes in.
A vaccine uses an inactive version of the virus to ‘trick’ the immune system into making an immune reaction and creating memory cells, without causing an actual infection. This often results in the patient feeling unwell or showing some mild symptoms of the virus, but this is just a sign of the immune system’s response.
Here’s where it gets more technical.
To trigger an adequate response to the inactivated virus, most vaccines contain what is called an adjuvant. This adjuvant is what actually stimulates the immune system, making sure it gets to the stage of making memory cells, and it’s the body’s response to this adjuvant that usually creates most of the side effects. But, the stronger the body responds, the more likely it is to create a good supply of memory cells, so that the next time the body encounters a virus, it can fight it quickly and efficiently.
The Biggest Issue With Cat Vaccinations
Like people, cats often suffer from various side effects of vaccination, including dizziness, fever, or swelling. It may not be pleasant for a day or two, but it is an expected reaction. True adverse reactions to the vaccine, where the injection triggers a severe allergic or systemic reaction, are extremely rare.
The worst possible side effect to vaccinations in cats is called injection site sarcoma – a type of malignant tumor that can develop where the vaccination was given. This ugly tumor requires aggressive treatment, including surgery to remove the mass.
Cat vaccines are traditionally given in the scruff, as there is a lot of loose skin, so it is easier to inject, as well as more comfortable and less stressful for the cat. But if an injection site sarcoma grows in this location, it is difficult, if not impossible, to completely remove the tumor because it often extends to the spine.
To combat this, it is recommended that cats be vaccinated on one leg, as this will allow amputation if necessary to completely remove the cancer. But, below our feet, there is less loose skin, and the injection is more painful and stressful, so it can be a case of weighing the risks and benefits, as well as finding other options. ways to reduce the chance of this effect.
Studies have found that the Feline Leukemia Virus Vaccine appears to have an increased risk of causing sarcoma, possibly due to the fact that the virus itself attacks the bone marrow and immune system.
One way to reduce the risk is to give leukemia vaccines every 3 years, instead of annually.
One company has created a non-adjuvanted vaccine, in the hope that it will result in less severe side effects, but this vaccine does not provide as long-term protection as the adjuvant-containing ones, so it must be given annually.
Risk/Benefit Analysis
This is where your decision making comes in. You need to be aware, and honest, about the type of risks your cats face, and talk to your vet about how to make sure they stay protected.
Cats in breeding colonies, housing conditions, or living outdoors with an increased risk of contact with other cats, should be vaccinated against leukemia virus according to the manufacturer’s recommendation.
For indoor cats, once they’ve received a complete basic vaccination course, and I generally recommend that they have their kitten course, plus one after a year, you might want to think about whether they need or not to proceed with this particular vaccination. While viruses such as cat flu can be transmitted through the air and on surfaces, the leukemia virus requires direct contact with the cat.
If you decide to go the route of not vaccinating against the leukemia virus, it’s important that you make sure any new cat entering your home has had a complete course of vaccinations, or been tested for the virus before coming into contact with your cat.
My cats are 100% indoor, and have not been vaccinated against the leukemia virus – they are at no risk of exposure. However, I vaccinate them against cat flu viruses every three years.
You might be wondering, Why is the use of the leukemia vaccine dangerous?
When a cat is infected with feline leukemia, there is a window of time where, if the virus is successfully cleared, the cat will live and develop natural immunity – Yay!
BUT, we don’t know how long that immunity lasts, AND if the virus isn’t cleared within that window of time, the cat will develop feline leukemia, a debilitating disease that often leads to suffering and death.
Some statistics:
- About 3% of cats in the United States and Canada are infected with feline leukemia.
- Feline leukemia is fatal in 80-90% of cases.
- The incidence of injection site sarcoma is between 1 in 1000 and 1 in 30,000 (0.1 to 0.003%).
Are vaccines safe?
Of course they are not completely safe – we are manipulating the immune system with an artificially modified version of a virus. Is that safe for you? But it’s a hell of a lot safer than taking our chances of surviving the actual virus.
The truth is, if we put something into the body to get a reaction, side effects are inevitable. If a drug or vaccine claims to have no side effects, it probably has no therapeutic effects either.
I hate that we live in a world where big pharmaceutical companies make money off of disease, and I think we are right to do research and ask questions.
BUT, the fact that big pharma makes money from vaccination, does not mean that vaccination is bad.
Is it really a shame that there are people who make billions from every viral outbreak? Absolutely! But that doesn’t mean we stop protecting our pets.
Natural immunity can work, but it only works if your cat survives.
