New FIV Vaccine!
FIV - Feline Immunodeficiency Virus

Published March 2002

In a major scientific breakthrough, the University of Florida and the University of California, Davis jointly announced the development of the first FIV vaccine for cats.

The U.S. Department of Agriculture granted a license that will enable Kansas-based Fort Dodge Animal Health to market the new product. The FIV vaccine is expected to be available from veterinarians as early as this summer.

The new vaccine was developed by Janet Yamamoto, a professor at University of Florida’s College of Veterinary Medicine who co-discovered the feline immunodeficiency virus in 1986 along with a former colleague, Dr. Niels Pedersen of the University of California, Davis. Yamamoto's continued study of the virus provided the foundation for developing the new vaccine.

This is the first time any type of vaccine to prevent animal immunodeficiency virus infection has been approved for commercial use.

FIV attacks a cat’s immune system, which is why it is sometimes referred to as feline AIDS. It is generally believed that transmission of FIV takes place through bite wounds inflicted during fighting.

Cats with FIV develop symptoms in three stages:

  • In the acute initial stage, cats show loss of appetite, transient fever, lethargy and have a low white blood cell count. Many cats recover from the initial phase and become lifelong carriers of the virus.
  • In the second stage, the cats exhibit no overt symptoms.
  • In the third stage, cats experience severe weight loss, and secondary infections that become resistant to treatment or frequently recur.
FIV has many biological similarities to the human immunodeficiency virus, or HIV, the cause of human AIDS. This is why FIV is sometimes called feline AIDS. For the same reason, procedures for protecting cats from FIV are hoped to aid in the development of human AIDS vaccines. No cat-to-human transmission of the FIV virus has ever been reported.

The new vaccine technology is based on viruses from cats who are called “long-term nonprogressors” - so named because the animals have been infected with FIV but take a long time to show symptoms of the disease.

The new vaccine is composed of two different FIV strains from two different subgroups of the virus from both the United States and Asia. These strains take a long time to cause disease, and once symptoms do occur, the disease is milder.

Instead of rapidly destroying the immune system, the virus remains at low levels in the cat while stimulating their immune system, allowing it to respond more effectively..

2% - 25% of the global domestic cat population is believed to be infected with the FIV virus. The numbers vary due to geographic region, ages of the cats, whether they are kept outdoors and other health problems they may have.

While the new vaccine seems like good news for cats, as with all new breakthroughs, there are many questions yet to be answered.

1) The most significant problem with the use of the new vaccine is the problem of how will veterinarians be able to differentiate between a cat who has FIV and cat that has been vaccinated with the new vaccine? The only test presently available will give a positive result in both situations.

In response to this issue, The American Association of Feline Practitioners have filed a protest with the Center for Veterinary Biologics, Licensing and Policy Development against the new vaccine. Licensing this vaccine makes it impossible for vets to tell the difference between an infected cat and a vaccinated cat since the standard FIV ELISA test detects antibodies, not the virus itself.

2) The new vaccine is a killed vaccine in an adjuvant. Will there be a possibility of vaccine associated sarcomas with its use?

3) Will the vaccine protect against all sub-groups of FIV?

4) Initial study results show that the new vaccine was 67% effective in protecting cats from FIV. But 26% of cats who were not vaccinated, also did not get the disease. If 26% of cats are therefore showing a natural immunity to FIV, does that mean that the new vaccine is really only protecting about 40% of the cats at risk?

5) Since FIV as a disease takes so long to develop, how do we REALLY know the vaccine is effective?

6) Will the average owner be willing to follow a protocol of a series of 3 injections to reach acceptable immunity levels?

Generally, it is never a good idea for cat breeders to rush to use a new drug, a new medication or a new vaccine until results of more field studies have been performed.

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