General recommendations on vaccine type and vaccination protocol

Both MLV and adjuvanted inactivated FPV vaccines are available for administration by injection, and both provide solid immunity against disease. In general, in a cat capable of mounting an appropriate response, MLV vaccines result in a more rapid protection (Green & Addie, 2005; Jevy et al. 2006a). However, also a single dose of an inactivated FPV vaccine may induce good antibody responses in naïve cats within a short time span (Levy et al. 2006a, Levy et al. 2006b). There are no data to suggest that particular vaccine brands are more efficacious than others.
In most situations, there is no reason to prefer one vaccine type to the other in an individual cat; MLV products are being used more generally, because of the more rapid onset of protection and a better resistance to MDA. Sometimes there may be considerations affecting this decision:

  • MLV FPV vaccines should not be used in pregnant queens because of the risk of placental virus passage to the foetus and damage, especially to the developing cerebellum (Pollock & Postorino, 1994; Greene 1998). In some countries, inactivated FPV vaccines are licensed for use in pregnant queens, but vaccination of pregnant queens should be avoided in general.
  • MLV FPV vaccines should never be administered to kittens under 4 weeks of age for the same reason: to avoid damage to the cerebellum which is still developing in young neonates (Pollock & Postorino, 1994; Greene, 1998).
Because of the serious consequences of an infection and because of the ubiquity of the virus, vaccination is recommended for every cat: a FPV vaccine is regarded as a core vaccine. Even cats with a strictly indoor lifestyle cannot always avoid encountering FPV, since the virus is so stable in the environment and can be transmitted on fomites (Pollock & Postorino, 1994; Greene 1998).

Primary vaccination course

Most kittens are protected by MDA in the first weeks of life. However, without serological testing, the level of protection and the point at which a kitten will become susceptible to infection and/or can respond immunologically to vaccination cannot be determined; also, there is considerable variation between individuals. In general, MDA will have waned by 8 to 12 weeks of kitten age to a level that allows an active immunological response, and an initial vaccination at 8 to 9 weeks of age followed by a second vaccination 3 to 4 weeks later is commonly recommended. Many vaccines carry data sheet recommendations to this effect. However, kittens with poor MDA may be vulnerable (and capable of responding to vaccination) at an earlier age, while others may possess MDA at such high titres that they are incapable of responding to vaccination until sometime after 12 weeks of age.
No single primary vaccination policy will therefore cover all potential situations. These are ABCD’s recommendations:

  • All kittens should receive FPV vaccines
  • A minimum of two doses – one at 8 to 9 weeks of age and a second 3 to 4 weeks later (at a minimum of 12 weeks of age) should be administered
  • If prophylactic administration of immunoglobulins is not possible, additional earlier vaccinations should be considered, especially if MDA is known or suspected to be poor and/or if the kitten is in a high risk situation. If a kitten is vaccinated at or before 4 weeks of age, this should only be done using an inactivated product, and repeat vaccinations can be done at 3 to 4 week intervals until =12 weeks of age.
  • In circumstances where MDA may have persisted beyond 12 weeks, vaccination at 16-20 weeks of age should be considered. This may apply to kittens in breeding catteries or cat shelters and to kittens from cats that had previously lived in a low-exposure environment and moved into a high risk situation. (Dawson et al., 2001)
  • Adult cats of unknown vaccination status should receive a single initial FPV vaccine injection (MLV) followed by a booster vaccination one year later.

Detection of nucleic acid

Cats that respond to FPV vaccination maintain a solid immunity for several years (seven or more), in the absence of any repeat vaccination or natural challenge (Scott and Geissinger, 1999; Lappin et al. 2002). Nevertheless, the ABCD recommends the following revaccination protocol:

  • All cats receive a first booster 12 months after completion of the primary vaccination course (this will ensure adequate vaccine-induced immunity for cats that may not have adequately responded to the primary course)
  • Following this first booster, subsequent revaccinations are given at intervals of three years or longer, unless special conditions apply.
While most cases of feline panleukopenia are caused by infection with FPV, variants of canine parvovirus (CPV-2a, CPV-2b, CPV-2c) have emerged that infect cats and may cause disease. Current FPV vaccines afford protection against these new CPV variants, although additional studies are needed to verify this (Chalmers et al., 1999; Nakamura et al. 2001).