by Jessica Vogelsang, DVM
When it comes to medicine, there is no “one size fits all” approach. This is particularly important when it comes to preventive care recommendations for our feline friends. Vaccine recommendations are among the most contentious debates in veterinary medicine, and it’s easy to be overwhelmed and confused when you hear conflicting information about how vaccines work and the adverse effects they may have.
Let’s face it: immunology is a complex topic, and vaccines for different diseases all vary in terms of how well they work, how common the diseases they protect against really are, and whether the benefit of protection outweighs the risk of giving the vaccine.
Fortunately for all cat lovers, some of the most dedicated feline veterinarians and scientists in the world have made it their job as the Feline Vaccine Advisory Panel to regularly evaluate the research and give recommendations based not on what we think or what we did in the past, but on today’s evidence. These guidelines, published in 2013 by the American Association of Feline Practitioners, are among the most trusted and utilized recommendations in the field. They have divided currently available vaccines into two categories: Core Vaccines and Non-Core Vaccines.
Core vaccines are those recommended for all cats, no matter where they live or under what conditions. These vaccines are: feline panleukopenia (FPV), feline herpesvirus-1 (FHV-1), and feline calicivirus (FCV). These diseases are highly infectious, found worldwide, highly dangerous to young cats, and the vaccines are considered highly protective with minimal risk. For this reason, all cats should receive these core vaccines.
Feline panleukopenia, also known as feline parvovirus, is a highly infectious disease with a high mortality rate in kittens. While the disease usually starts with decreased energy and low appetite, it progresses to vomiting and diarrhea. The virus also kills off the white blood cells, leaving the young cats even more susceptible to secondary infections.
Feline herpesvirus, also known as feline rhinotracheitis virus, causes severe signs of upper respiratory infection, such as sneezing, nasal congestion and discharge, and conjunctivitis. In some cases it also causes oral ulceration and pneumonia. After the cat recovers from the initial infection, the virus enters a latency period in the nerves. During times of stress, the virus can re-activate, and the cat again shows signs of infection even if he or she has not been re-exposed to the disease.
Feline calicivirus encompasses a number of viral strains which cause signs of upper respiratory infection, such as sneezing and nasal discharge, as well as oral ulcerations. FCV is thought to be associated with chronic gingivitis/stomatitis, a very painful inflammation of the gums and teeth. Some of the more virulent strains cause hair loss and crusting on other parts of the body as well as hepatitis and even death.
Kittens under six month of age are most susceptible to infectious diseases, so they are considered a primary focus of vaccination recommendations. Maternal antibodies passed on from the mother are meant to confer some degree of protection from these infectious diseases in young kittens, but also interferes with or even inactivates the body’s response to vaccination. For this reason, initial core kitten vaccinations occur at 3-4 week intervals until the cat is 16-20 weeks old and maternal antibody is out of the system. For adults whose vaccine history is unknown, the initial series consists of two doses of vaccine, 3-4 weeks apart.
Core vaccines should be boosted 1 year after the initial series. The scientific community is still learning exactly how long these vaccines last, so every 3 years is recommended to ensure protection. Cats heading into stressful situations such as boarding may benefit from a core vaccine booster 7-10 days before.
Vaccines which are appropriate for some cats in some circumstances are considered non-core vaccines. These vaccines are: rabies, feline leukemia virus (FeLV), feline immunodeficiency virus (FIV), Chlamydophila felis, Bordetella bronchiseptica, feline infectious peritonitis (FIP) and dermatophyte. Of these, only FeLV and rabies are recommended for all household pet cats. Vaccines that are not on this list are not recommended.
Rabies is significant not only for its effect on the cat, but because it is a disease that is transmissible, and fatal, to humans. While cats are not a natural reservoir for the disease, they can be infected by a bite from any infected mammal and pass it on to others. After an incubation stage averaging two months, clinical signs of aggression, disorientation, and death rapidly progress. Rabies is endemic worldwide and is recommended for all pet cats.
The general vaccination schedule for rabies includes a single dose of vaccine that is boosted in one year, then every three years after that. Local laws regarding rabies vaccines in cats usually takes precedence over this recommendation; talk to your veterinarian if this is a concern. Cats who experience a reaction to rabies vaccine should not be re-vaccinated.
Feline leukemia virus is found worldwide. Transmitted through body fluids including saliva, urine, and feces, cats are usually infected through close contact with another cat that they groom or share bowls with. Infection with FeLV is not an automatic death sentence. Many cats are fortunate to go into a regressive state and appear perfectly healthy throughout their lives, but some do not. After a latent period lasting months or even years, the disease progresses to a variety of associated conditions: lymphoma, anemia, or immunosuppression resulting in secondary disease.
The initial vaccination series consists of two doses 3-4 weeks apart, followed by revaccination one year later for all pet cats. Based on most recent data, the Vaccine Advisory Panel recommends subsequent vaccines may be administered based on risk: yearly for high risk cats, and every two years for lower risk cats.
No injection or medication is without some degree of risk, but we continue to vaccinate because in most cases it is much smaller than the risk of the disease itself. The overall incidence of adverse reactions in cats is reported to be about half of one percent and usually mild and self-limiting: lethargy, transient fever, and local inflammation. Anaphylaxis and death are, fortunately, extremely rare: about 1 in every 10,000 vaccines.
Vaccine associated sarcomas, a slow-growing but locally aggressive cancer associated with injections, occurs with about the same rare frequency as anaphylactic reactions. For cats without a history of vaccine reactions, the risk of sarcoma is usually outweighed by the benefit of the core vaccines. Pet owners can minimize the impact of sarcomas by monitoring injection sites for swelling after vaccinations. Swellings should be biopsied if they are larger than 2 cm, persist longer than three months, or grow one month past the date of vaccination. When addressed early, surgery is often curative.
Many factors affect the likelihood of a cat developing an infectious disease, which is why a thorough medical history is essential to determining each cat’s recommended care. Such factors include the cat’s age and medical history, how likely they are to be exposed to the pathogen, the severity of disease caused by the pathogen, and whether or not the cat has been vaccinated in the past. If the benefit to the cat is greater than the likelihood of a bad reaction, the cat should be vaccinated.
With these recommendations as a starting point, you can discuss your cat’s lifestyle and risk factors with your veterinarian to determine the optimal, individualized vaccination protocol for your furry friend!