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Summer Street Cat Clinic

When to Vaccinate your Cat

Some inoculations are vitally necessary, but for most cats, they should be kept to a minimum. Here’s why.

In the past 50 years, there have been many vaccines developed that can protect your cat against a wide variety of lethal feline diseases. Before the invention of the feline panleukopenia vaccination, half of all cats that passed through a shelter developed panleukopenia within a few days and as many as 90% of them died from it. Today, the FPV vaccine (included in the FVRCCP vaccine) has totally controlled the disease in vaccinated cats. The only time it is seen now is in unvaccinated feral or shelter cats, but that is rare.

However, there are several reasons why owners should refrain from having their cats inoculated annually with every available vaccine. There is the potential for cats to have reactions to vaccinations. In rare cases, some cats even develop a sarcoma, a type of cancer that, for unknown reasons, emerges at an injection site on a cat’s body. 

Research has brought into question the need for all cats to be routinely revaccinated with all available vaccines every year throughout their lives. As the result of a previous vaccination, the antibody levels in a cat’s blood often remain high enough, leaving the animal protected against the disease. 

Many veterinary organizations now agree that vaccination should be regarded as a complex medical procedure and should therefore be undertaken with correspondingly serious consideration. They also agree that no vaccine is always safe, no vaccine is always successful in preventing infection, and no vaccine is always appropriate. Therefore, vaccine protocols should be determined for cats on a case-by-case basis. 

In 2006, the AAFP Feline Vaccine Advisory Panel placed the 10 available feline vaccines into three categories: “core,” “non-core” and “not generally recommended.”


There are four core vaccines currently available. These offer protection against:

  • FPV (feline panleuokpenia virus) - which cases a highly and often fatal contagious disease that is marked by fever, vomiting, diarrhea, and dehydration

  • FHV (feline herpes virus) - which causes severe upper respiratory distress

  • FCV (feline calicivirus) - which causes infection of the respiratory system and ulcers of the oral cavity

  • Rabies Virus – which causes inevitably fatal disease affecting the central nervous system.

The FPV, FHV, and FCV are all included in 1 injection, often referred to as the “distemper” vaccine. Kittens should be vaccinated as early as six weeks and receive booster shots every three to four weeks until they are about 16 weeks old. Another revaccination should be administered one year after the initial vaccination, and booster shots should be given every one to three years thereafter.

For the rabies virus, an initial vaccination should be administered when a kitten is about 12 weeks of age, with a booster shot one year later and additional booster shots every three years thereafter (or as required by state or local ordinances).


  • FeLV (Feline Leukemia Virus) – which can directly or indirectly cause several feline diseases such as lymphosarcoma, a cancer of the lymphnodes.

  • FIV (feline immunodeficiency virus) – which can weaken a cat’s immune system and subject the animal to numerous opportunistic diseases

Determining which cats should be inoculated with the non-core vaccines, at what age, and how often continues to be the subject of debate. There are many factors such as the cat’s age, living environment, risk of exposure, and the likelihood that infection will lead to serious disease.