Most vaccination courses start with two separate injections about three weeks apart. This course must be completed before your kitten is fully protected by the vaccine. The protection given by most vaccines wears off in time and at different rates for each particular vaccine. The level of infection in the environment of many of the diseases against which we vaccinate is low. This means that it is unlikely that a vaccinated animal will come into contact with the wild strain virus sufficiently frequently to receive natural boosts to its immunity.

Repeated vaccination is necessary to maintain adequate antibody titres in these cases. If your cat has not been given a booster for more than two or three years, your vet may think it is safer to start from scratch with a new course of injections. It is particularly important to make sure boosters are up to date in cats that fight regularly with other cats. Most catteries will insist on seeing proof of regular vaccinations before looking after your cat.