Vaccines help a cat's immune system fight off common illnesses by exposing the cat to the illness in minuscule amounts, allowing the cat's body to develop the proper anti-bodies to fight it off if it comes into contact with that illness. When you bring your kitten to the vet the first time, the vet will recommend certain vaccinations depending on: the age and health of the kitten, whether the kitten is indoor or outdoor, and the number and type of other pets you may have as well.
The most common types of vaccinations include: Feline Leukemia (FeLV), Feline panlleukopenia, Feline Respiratory Disease (Rhinotracheitis, Calicvirus, and Chlamydia), and Rabies. These are all very common ailments in cats which can cause death or severe side effects. These vaccinations are essential, especially for cats who go outside or who are exposed to other animals.
Most cats do not suffer from any side effects from these shots. It is not uncommon for the cat to be less active for a few days after them, but they should not cause any problems. After the couple days, the cat should be fine. Severe reactions are extremely rare. If you notice any of the following symptoms, bring the cat to the vet immediately: vomiting, diarrhea, or lethargy.
If you have a young kitten, they will often be required to obtain a sequence of vaccinations. The reason for this is that a kitten naturally gets antibodies from its' mother's milk. These antibodies are good for the cat, but make vaccinations not work correctly. So, the cat will be given its first set of vaccinations when it is a few weeks old, and then a second one will be given a few weeks later after the natural antibodies have left the cat's system.
There has recently been some concern that Adjuvants can cause cancer or immunological disease later in life. Adjuvants are added to vaccines in order to increase the effectiveness. Most vaccines are injected, but there are nasal spray vaccines available as well. It can take up to 14 days for the vaccine to become effective. If you have any special requests like these, make sure to speak to your vet before having the vaccine administered.
You will likely need to get your cat booster vaccines every one to three years. The vet will decide how often the cat needs the boosters depending on age, type of vaccine, current state of health, and the environment of the cat. These are essential to make sure that the cat maintains its vaccination.