can vaccines cause anemia?

by Paula
(St Pete, Florida)

Our cat was sneezing and had a runny nose. She did not appear to be sick other than that. I took her to the vet and he said she was fine but due for FVRCP, which they gave that day. Two weeks later she was back to vet due to vomiting, loose stool, not eating well, lethargic. Blood tests revealed she was anemic. Could those shots cause anemia?


I’m replying a little later than normal because we expanded our July 4th to include the weekend.

FVRCP stands for Feline Viral Rhinotracheitis (herpes), Calici, Panleukopenia (feline distemper). This is a combination vaccine for 3 problems. Herpes and Calici are upper respiratory viruses that can cause watery, swollen eyes, nasal congestion, sneezing and even oral ulcerations. Although the illness can range from very mild to severe there is a low mortality rate…much like a human cold can effect different people with varying intensities but most of the time isn’t deadly. However, the Panleukopenia (feline distemper) is a highly contagious virus that infects the intestines and it causes bloody diarrhea and vomiting. This has a very high mortality rate.

The FVRCP is known to cause kidney inflammation and a good case is being made that it causes chronic kidney disease. This is currently being documented. Data is being compiled to back up that finding by several research universities specializing in feline disorders. Annual vaccinations have been discouraged for around 15 years and they were changed to every 3 years.

But even every 3 years has risks that a cat owner must consider. When you realize that a single FVRCP vaccine, at the appropriate time (which is estimated to be somewhere between 4-6 months), results in life-long immunity to panleukopenia (the serious part of the trio) it pretty much eliminates the urgency to keep repeating this vaccine. The Herpes and Calici parts only reduce the severity of those infections and don’t eliminate them entirely. Since death is very rare from those two parts of the vaccine a cat owner has decisions to make.

The AAFP guidelines will vary from what some pet owners and vets choose to do. Those guidelines change periodically after there is enough data to make it expedient to do so. You have to discuss with your vet what is recommended by him/her. I am not a vet but I do a lot of research on topics done by numerous veterinarians and university studies and follow what I find most comfortable in doing for my own cats. They no longer get FVRCP vaccines now that they have had their initial shots and a booster.

You were thinking that perhaps your cat receiving this vaccine recently caused anemia. Although it’s highly unlikely…it’s not impossible but still very improbable. Hemolytic anemia results from the abnormal destruction of red cells and is of the regenerative type. In other words, your cat’s own immune system is fooled into “thinking” that the red blood cells are foreign…and destroys them. There are numerous conditions that can trick the immune system into behaving in an irregular manner such as infections, cancer, allergic reactions to medications, poisoning, blood parasites etc. but there are no studies suggesting vaccinations cause this problem. The most common cause of nonregenerative anemia is due to inadequate production of red blood cells by the bone marrow and the most common cause is feline leukemia virus.

Your veterinarian will probably do more testing to try to resolve the anemia since it is best taken care of by treating the underlying cause. Perhaps a titer blood test will be done but there are other options to discuss with your vet. It would appear that the anemia has appeared coincidentally and was not caused by the vaccine, but strange things do happen.

I’d be interested to know what your resolution is. Please email me and let me know. The contact information is on my “Privacy & Contact page” listed on a button at lower, left side of the page.

Comments for can vaccines cause anemia?

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Jun 13, 2018
same problem with post vaccine of fvcrp
by: Anonymous

my cat got the trio vaccine when she was 11months old, and found to be severe anemic three months after. she was totally fine before vaccine and she is indoor cat, never contact with any other causes.Her parent both healthy, the vet said this is due to some virus infection which the vaccine did not cover for sth called"PUF"? ultra sounds revealed that her lymphanodes are swellen!She even suggested to put her down! What I can do for it?

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