Vaccination schedules

Most data sheets recommend primary vaccination for kittens followed by annual boosters thereafter. Such regimens maximise protection for the individual and are generally based on both experimental challenge studies and field data provided by the manufacturer. However, in recent years there has been considerable discussion as to whether such schedules are always appropriate, largely because of concerns about possible safety issues. These issues have been particularly highlighted by the increasing use of inactivated adjuvanted vaccines in cats, and the possible association between such vaccines and the formation of vaccine-associated sarcomas.

Because of these concerns, some authorities in the USA have designated certain vaccines as 'core' vaccines, such that all animals should undergo primary vaccination as indicated by the manufacturer, followed by revaccination 1 year later and then boosters every 3 years. A vaccine is designated as core either if the consequences of infection are particularly severe (e.g. feline panleucopenia) or the prevalence of disease is high and the disease is easily transmitted (e.g. feline herpesvirus and feline calicivirus infection). In the USA and some other countries where rabies is endemic and poses a substantial zoonotic risk, rabies vaccines are mandatory and are also considered core vaccines. Other vaccines are designated 'non-core' and it is recommended that they should only be used following a risk/benefit assessment.

In the UK a recent Veterinary Products Committee working group report on feline and canine vaccination concluded that, based on currently available evidence, booster vaccination protocols recommended by the manufacturer should in general be adhered to (Gaskell et ah, 2002a, b). However, it was emphasised that the regimen for booster vaccination is based on a minimum duration of immunity rather than a maximum and that a risk-benefit assessment should be carried out for each individual animal by the veterinary surgeon in consultation with the owner. Thus, an informed choice may be made by the owner with respect to the necessity of a particular vaccine and the frequency of its use. Such a consultation should include discussion on the likelihood of exposure, available data on the duration of immunity, and the risks related to vaccination. It was also suggested by the working group that, where possible, manufacturers should continue to market single-component as well as multivalent products to retain flexibility.

Age (days)

Figure 2.1 Diagrammatic representation of the concept of the immunity gap. The actual age at which the immunity gap develops depends on the amount of maternally derived antibody (MDA) transferred to each kitten.

Age (days)

Figure 2.1 Diagrammatic representation of the concept of the immunity gap. The actual age at which the immunity gap develops depends on the amount of maternally derived antibody (MDA) transferred to each kitten.

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