Cat Vaccination Adverse Reactions
It is useful for a cat caretaker to know of the likelihood of a cat vaccination reaction and the type of reaction.

Vaccination Necessary?
A large British survey produced the following information:
Adverse reactions occurred in one in every 15,000 inoculations. They usually occur in cats under the age of 6 months.
The adverse reactions in descending order of prevalence are:
- lameness/polyarthritis – 18%
- local injection site reaction – 9%
- lack of efficacy (failure of the inoculation) – 6%
- upper respiratory tract disease – 6%
- sarcomas (tumors)- 3%
Sarcomas are perhaps the best known adverse reactions. They are not caused by the vaccination itself but a genetic predisposition by the cat to developing a sarcoma after an area becomes inflamed for whatever reason. The incidence of injection-site sarcomas is estimated to be one on ten thousand to thirty thousand (1 in 10k-30k).
A well known vet/author Dr Fogle tells us how he vaccinates his cats. He vaccinates kittens against feline infectious enteritis and the cat flu viruses feline herpes virus-1 (FHV-1) and feline calicivirus (FCV). See a page on feline viruses.
The American Academy of Feline Medicine and the American Association of Feline Practitioners both recommend that there should be a first annual booster and thereafter no more frequently than every three years for feline infectious enteritis and ‘in general’ no more than every three years for FHV-1 and FCV.
In Britain boarding catteries often demand proof of vaccination within the past 12 months. This clashes with the above guidelines.
Dr Fogle does not vaccinate his cats against the following:
- Bordetella bronchiseptica which can cause sneezing in cats and a nasal discharge. This disease responds well to antibiotics.
- Feline chlamydophilosis which causes severe conjunctivitis which can be treated with antibiotics. Vaccination does not necessarily prevent infection.
- Feline coronavirus. An intranasal vaccine is available in many places but its effectiveness is questioned.
- Feline immunodeficiency virus (FIV). In the USA a vaccine is available but its effectiveness has been questioned.
Testing for levels of protection against infection by serological testing (testing of blood serum) is not reliable according to Dr Fogle.
Cat vaccination recommendations have evolved and changed over the years. The trend is towards less, as you probably know, because the downsides can begin to outweigh the upsides. However, I feel the situation is rather confused. It is tricky for the customer cat caretaker to formulate opinions of their own. I don’t know if people will disagree or agree with that but it is the way I feel about cat vaccination recommendations.