Core Vaccinations for Cats

The veterinary community has divided vaccines into two main categories, with a smaller third category. Core vaccines are vaccines that every cat should have at some time in his life. Noncore vaccines are vaccines that only some cats need, depending on factors such as geographic location and lifestyle. Other vaccines are also available but are generally not recommended for any cats.

Panleukopenia (Core)

The first panleukopenia (FPV) shot should be given at 6 to 8 weeks of age, before a kitten is placed in a new home where he may be exposed to other cats. If the kitten is at particular risk in an area where the disease has occurred, vaccination can be given at 6 weeks of age and then every three to four weeks until the kitten is 16 weeks old. Discuss this with your veterinarian.

After the initial kitten series, a booster given at 1 to 2 years of age may be sufficient in cats who mix with others, because exposure to the disease boosts immunity. A booster after one year is recommended, and then no more frequently than every three years.

Two types of injectable vaccines are available. One is a killed virus and one is a modified live strain. An intranasal vaccine is also available. The modified live virus vaccine is not recommended for pregnant cats or kittens younger than 4 weeks. Killed virus vaccines may be more appropriate in disease-free colonies because there is no risk of reversion to virulence.

Panleukopenia vaccine is often combined with the feline viral respiratory disease complex vaccines and given as a single injection.

Feline Viral Respiratory Disease Complex (Core)

Your veterinarian may recommend an injectable vaccine containing strains of the herpesvirus (FHV) and calicivirus (FCV). Usually, they are combined with panleukopenia vaccine and given at least twice as a single injection, with the last vaccination not before 16 weeks of age. Kittens may be vaccinated as early as 6 weeks of age.

Adolescent and adult cats should receive two initial doses, administered three to four weeks apart. In both kittens and adults, a booster after one year is recommended, and then every three years.

Although viral respiratory disease vaccines are highly effective, they do not prevent all cases of illness. The cat can be exposed to individual strains of virus that are not countered by the vaccine, or the infection can be so severe that it overcomes the cat's protection against it. When this happens, the resulting disease usually is milder than it would be in an unvaccinated cat. Vaccination will not prevent carrier states in cats who do become infected.

Vaccines for the respiratory viruses are available as injectable modified live virus, injectable killed virus, and modified live intranasal. The intranasal route may produce sneezing and nasal discharge. The killed virus vaccine is preferred for pregnant queens and in disease-free colonies because there is no risk of reversion to virulence.