Generally, the immunity that a kitten has at birth begins to diminish after 9 weeks. It is then usually time to begin the initial vaccinations, with the booster following 3 to 4 weeks later until they are 4 months old. Thereafter, your cat will require repeat vaccinations for the rest of his or her life. Of course, these are only guidelines - your veterinarian will be able to determine the exact schedule that's right for your pet.

Which vaccinations should my cat receive?
Your cats/kittens should be protected against those diseases which are most common, highly contagious and which cause serious illness. Such diseases could include Feline Panleukopenia, Feline Viral Rhinotracheitis, Feline Calicivirus, Feline Chlamydophila, Feline Leukemia and Rabies. Other vaccinations may be recommended, based on your evaluation of the risks posed by such factors as your cat's particular heredity, environment and lifestyle.

1. Feline Viral Rhinotracheitis
Just as with the human common cold, the virus that causes this upper respiratory-tract infection is easily transmitted from one cat to another, so vaccination is imperative if your pet will come in contact with other cats. Its symptoms may take the form of moderate fever, loss of appetite, sneezing, eye and nasal discharges and coughing. Kittens are particularly affected, but this disease can be dangerous in any unprotected cat, as effective treatment is limited. Even if a cat recovers, it can remain a carrier for life.
                              
2. Feline Calicivirus
This virus is another major cause of upper respiratory-tract infection in cats. Widespread and highly contagious, its symptoms of fever, ulcers and blisters on the tongue and pneumonia (inflammation of the lungs) can range from mild to severe, depending on the strain of virus present. Once again, treatment of this disease can be difficult. Even if recovery does take place, a recovered cat can continue to infect other animals, as well as experience chronic sneezing, runny eyes, and severe gum disease. Vaccination is therefore tremendously important.
3. Feline Panleukopenia
Sometimes known as feline distemper, this disease is caused by a virus so resistant, it can survive over one year outside a cat's body! Therefore, as most cats will be exposed to it during their lifetimes and infection rates in unprotected cats can run as high as 90% to 100%, vaccination against this usually fatal disease is absolutely essential. Symptoms can include listlessness, diarrhea, vomiting, severe dehydration and fever. Happily, the vaccine itself is very effective in preventing the disease, as treatment is very difficult and, even if recovery takes place for a period of time, a once-infected cat can spread the disease to other, unvaccinated animals.
4. Rabies
This incurable viral disease affects the central nervous system of almost all mammals, including humans. It is spread through contact with the saliva of infected animals (which can include skunks, foxes, raccoons and bats) through bites or any break in the skin. Vaccination will provide your cat with much greater resistance to rabies if he is exposed to the disease, but you must be aware that there is no cure once it occurs. For this reason, it is required that all cats receive rabies vaccinations on a regular basis. Plus, you will definitely have to prove that your cat is vaccinated if you ever have to travel with him - whether across the country or around the world.
5. Feline Leukemia (FeLV)
Infection with the Feline Leukemia Virus can result in a multitude of serious health problems for your cat - everything from cancerous conditions such as lymphoma to a wide range of secondary infections caused by the destruction of the immune system. In fact, it is the leading cause of death in North American cats. After initial exposure to the virus, a cat may show no symptoms of its presence for months, if not years, yet all the while infect others. Testing is available to determine the FeLV status of your cat. If he or she has not yet been infected, but is likely to come in contact with cats that are, vaccination against this fatal disease is highly recommended.
6. Feline Chlamydophila
This bacterial disease is responsible for 5% of all feline respiratory diseases. It is extremely contagious, especially in young kittens and the infection rate is very high. It causes a local infection of the mucous membranes of the eyes but may also involve the lungs. Chlamydophila can be transmitted to humans by direct contact. Vaccination is the preferred method for prevention.

Other Vaccinations
After evaluating your cat's particular situation and risk factors, your veterinarian may also recommend vaccination against other infectious diseases. But that determination is made based on your cat's life style and potential of coming into contact with these rarer diseases.

How effective is vaccination?
Like any drug treatment, vaccinations cannot be 100% guaranteed. However, used in conjunction with proper nutrition and acceptable sanitary conditions, vaccination is clearly your pet's best defense against disease. Plus, when you consider what treating a serious illness can cost you and your beloved cat in terms of both money and distress, prevention through vaccination is extremely cost-effective.