Noncore 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.
Feline Leukemia Virus (Noncore)
The development of a vaccine against retroviral infection is a long-awaited
achievement in veterinary medicine. However, this vaccine is not 100 percent
effective. It is possible that some cats vaccinated for FeLV may still become
This vaccine is noncore because of its incomplete effectiveness and because
indoor cats who have been tested before coming home should have minimal risk of
acquiring FeLV and therefore should not need this vaccine. Kittens born to
immune queens acquire protective antibodies in the colostrum of the queen. This
protection begins to disappear at 6 to 12 weeks of age, after which kittens are
Cats with access to the outdoors or who roam free may need this vaccine.
However, since kittens are most susceptible to FeLV and may escape, some
veterinarians recommend vaccinating kittens and giving a first booster at 1
year. If the cat is then firmly established as an indoor-only cat, no more
boosters are needed.
Testing for FeLV is recommended before vaccination. Vaccination is not
effective if the cat is positive and already infected. If the ELISA test is
negative, vaccinate kittens at 8 to 12 weeks of age and again at 14 or 16
weeks. The first booster is given one year later.
To be effective, a full course of vaccination must be administered. This
involves two vaccinations two to three weeks apart, a booster a year later, and
then annual boosters, if needed.
Vaccines available include injectable adjuvanted killed virus, nonadjuvanted
recombinant for transdermal use, and, in Europe, a nonadjuvanted recombinant
for subcutaneous injection. According to recommendations of the
Vaccine-Associated Sarcoma Task Force, FeLV vaccines are administered
subcutaneously as distally as possible in the left rear limb.
Feline Immunodeficiency Virus (Noncore)
The FIV vaccine is an inactivated, killed, injectable
vaccine. Unfortunately, vaccination of FIV-negative cats causes the serologic
tests that are currently available to read as positive. In addition, previous
vaccination does not rule out infection, so the significance of a positive test
result in a vaccinated cat cannot be assessed. There is concern that the
subtype of virus used in the vaccine may not protect against the more common
subtypes of the disease. Therefore, the risks and benefits of the use of this
vaccine should be carefully discussed with your veterinarian.
Chlamydophila felis (Noncore)
Chlamydophila felis causes feline pneumonitis in cats. Immunity induced by
vaccination is probably of short duration and the vaccine provides only
incomplete protection. Vaccinated cats can still come down with pneumonitis but
usually have a shorter, milder illness. The use of this vaccine could be
considered for a cat entering a population of cats where infection is known to
be endemic. However, the vaccine has been associated with adverse reactions in
3 percent of vaccinated cats.
Bordetella bronchiseptica (Noncore)
This is a modified live intranasal vaccine. Bordetella bronchiseptica is
primarily a problem of very young kittens, where it can cause severe lower
respiratory tract disease. It appears to be uncommon in adult cats and pet cats
in general, and should respond readily to antibiotics, so vaccination is generally not