Guidebook: Feline Panleukopenia

Chapter 2: Vaccination

Vaccination for FPV is highly effective if performed correctly. A thoughtful and effectively implemented vaccine program can substantially reduce spread of infection in a shelter. Modified live subcutaneous vaccination will provide more rapid protection than killed vaccine, which requires a booster to be effective.

All cats four weeks of age and older should receive a modified live panleukopenia vaccine immediately upon shelter entry. Cats begin mounting an immune response to panleukopenia immediately and develop full immunity in three days.1  A delay of even a few hours renders the vaccine far less useful. Even injured and mildly ill cats should be vaccinated. 

For pregnant cats expected to carry kittens to term, balance the risk of inducing abortion or birth defects (reportedly very uncommon with currently available vaccines) against the risk of death of mom and kittens from virulent disease. Additionally, vaccinating the queen for the respiratory viruses contained in the FVRP vaccine can confer some protection to the kittens by generating maternal antibodies. In most cases, the benefits outweigh the risk of vaccination. However, for pregnant cats seized as part of a legal case or cats in a shelter where the risk of panleukopenia is extremely low, a killed vaccine may be preferable. 

Vaccination recommendation summary:

  • Vaccinate all cats > four weeks old (including injured and mildly ill) immediately upon intake with a modified live subcutaneous FVRCP vaccine.
  • Vaccinate pregnant cats unless part of a legal case or where the risk is extremely low.
  • Re-vaccinate all cats under 18-20 weeks every two weeks while in shelter.
  • Re-vaccinate all cats in foster care at least one week prior to shelter return.
  • House unvaccinated cats, if any, off site or in an area carefully segregated from at-risk populations

Vaccine warnings: 

  • Vaccination with MLV FVRCP in pregnant cats may cause birth defects or abortion. However, this has rarely been documented. This risk must be balanced against the risk of panleukopenia in the shelter in deciding whether or not to vaccinate pregnant cats.
  • MLV FVRCP vaccine may cause serious upper respiratory infection if administered intranasally, or even if a cat licks up spilled vaccine. Do not draw vaccine up in front of the cat’s nose, and clean vaccine spilled on the fur immediately with alcohol.
  • MLV vaccination may cause a weak false positive parvo SNAP tests within about 5-12 days after vaccination.

 For more information, refer to Vaccination in Animal Shelters and the American Association of Feline Practitioners Vaccination Guidelines.

Related Reading

Is it advisable to use a 1/2 dose of FVRCP for 6 week old kittens?

Splitting vaccines for any species should never be done. Dr. Aziz confirms that a full dose of vaccine is needed to stimulate the immune system and includes references to studies supporting her assertion.

Vaccination in Animal Shelters

Vaccination is an integral component of any shelter or rescue organization's overall population health management program. Every shelter must develop a vaccination protocol that is tailored to their population's needs, and shelters must be ready to adapt their protocol if changes in overall population health are observed as part of a routine health monitoring program.

Is there a maximum number of FVRCP vaccines a kitten should receive between 4-20 weeks?

Repeated vaccination of kittens in a shelter setting starting as early as 4 weeks of age and repeated every 2 weeks until 20 weeks of age is necessary to reduce risk in the face of disease exposure. Still the best way to ensure kitten health is to get them out of the shelter as soon as possible.