We recommend that all kittens are vaccinated at around 9 weeks then again at 12-15 weeks and annually after that throughout their lives. The purpose of the first 2 injections 3-6 weeks apart (the primary course) is to stimulate the body to produce it's own natural protection from the diseases that we vaccinate against in cats.
The most basic cover that we offer protects your cat against the two viruses that cause "cat flu" and another called Feline Panleucopaenia Virus that affects white blood cells and gut. These viruses are potentially spread on clothes and shoes as well as from cat to cat so even pets that never leave the house should be vaccinated.
There are also vaccines available that cover your pet against Feline Leukaemia Virus FeLV) and Feline chlamydophila. FeLV is a virus that damages the white blood cells of your cat leading to a weakened immune system. In many cases it can also lead to tumours. It is spread through saliva, nasal secretions and blood meaning any outdoor cat involved in a fight may potentially contract the disease. For this reason we suggest that all outdoor cats are vaccinated against FeLV. Feline chlamydophila is a bacteria that causes persistent infections in the eye and respiratory tract.
The immunity that these injections create gradually wears off over the course of a year, hence it is necessary to get this immunity "boosted" with annual injections. Your annual booster is also a good opportunity for the vet to check your cat over and give you any advice that you may need.
If you acquire a cat that has never had vaccinations, you wish to start an older cat, or you have missed your annual booster by more than a couple of months, it will be necessary to complete the primary course of 2 injections 2-4 weeks apart to guarantee protection.