There are a number of highly infectious and potentially fatal diseases that can affect your cat. However, for most of them, there is a protection that is simple and effective in the form of a vaccine. It is important to make sure that your cat has received the first series of injections useful for such a prevention, then that it continues to be protected through the boosters that certain vaccines require to keep a good health for life.

How do vaccines work?

Most vaccines are given by simple subcutaneous injections. Some can be given nasally, using a spray. All vaccines work the same way, that is, they stimulate your cat's white blood cells to recognize and then attack the viruses or bacteria present in the vaccines. It is the antibodies thus produced by the vaccines that will prevent infection in the event that the cat is again in contact with these same organisms.

Animation illustrating antibody formation and then virus destruction by these same antibodies:

Vaccines can be split into two categories: 'live vaccines' which contain altered (or attenuated) strains of the infectious agent in such a way that it cannot develop disease, but which stimulate immunity, and 'killed vaccines' where the organism has been destroyed either chemically or by heat. Each of these types offers advantages and disadvantages: live vaccines generally produce longer and stronger immunity, but they sometimes have side effects. They are not recommended for pregnant cats, for example.

How do I know which vaccines are useful for my cat?

There are several vaccines available for cats today, but not all cats need all vaccines each year. We can classify today the groups of vaccines into 'core vaccines' and 'non-core vaccines'. 'Core vaccines' are generally considered to be those that should be administered every year because of the highly infectious nature of these dangerous agents and also their widespread presence in the environment. 'Non-core vaccines' correspond to diseases which are not always predominant or which do not present the same degree of risk and which may therefore not be considered. The decision to use either of these 'non-core vaccines' will depend on your cat's lifestyle and the local risk in your territory.

Lifestyle risk factors are key to this decision and helpful questions you should answer are:

  • How old is my cat and where is he/she from?
  • Where and how does he/she live?
  • Are there other animals in the household?
  • Is he/she going out? Is it in a city or in the country?
  • Do you plan to keep him in a boarding cattery?
  • Is he sedentary or on the contrary out all the time?

These questions will have a direct impact on needed vaccines to consider.

Whatever its environment, the majority of veterinarians recommend vaccination against respiratory viruses (herpes and calicivirus), and against typhus (panleukopenia). These vaccines are considered basic. Cats that go outside and may come into contact with other cats are at risk for feline leukemia, and as a result most experts also consider the vaccine against the FeLV virus, responsible for feline leukemia, as a core vaccine as well. On the other hand, there are many cats who never meet other cats. If your cat is strictly an indoor cat, talk to your veterinarian who will judge, as for rabies, that the risk is not sufficient to justify these vaccines.

What are the diseases against which vaccines can be recommended?

Feline panleukopenia(often called "cat distemper" or "feline viral hemorrhagic enteritis")

  • Before the existence of an effective vaccine, this disease was undoubtedly one of the most devastating and responsible for high mortality in cats. It is particularly dangerous for kittens and young cats, in which vomiting and diarrhea can cause dehydration and a fatal outcome 2-3 days after the first symptoms appear. The virus is disseminated in feces and resists in the environment for long periods.

Animation illustrating the infection associated with cat distemper:

Feline rhinotracheitis (also called Cat Upper Respiratory virus) is caused by either herpes viruses or caliciviruses

  • Almost all cases of respiratory tract disease in cats are caused by one of the herpes viruses or caliciviruses.
  • Feline rhinotracheitis is rarely fatal, except in very young cats or in cats with other concomitant diseases and therefore more fragile. Exceptionally, we may be in the presence of viruses with very aggressive strains. In these fortunately rare cases, the vaccines do not seem to have any effect.
  • The symptoms of feline rhinotracheitis are the same as those seen in humans with a common cold, namely sneezing, runny nose, runny eyes, then coughing and difficulty breathing. In some cases, mouth ulcers are observed. Once infected, the cat can carry the virus for a long time and be a risk of contagion for other cats.
  • Some cats carrying the virus may show no symptoms or on the contrary may show mouth ulcers or permanently runny eyes. In some cases the protection provided by vaccination may be short-lived, and therefore there is need for more frequent booster shots, such as every 6 months.

Feline Leukemia (FeLV virus)

  • This is a severe viral disease in cats. Not all cats infected with the virus are sick, so there are 'healthy carriers'. On the other hand, almost all those who are also affected by the disease will die. Treatments are most often palliative and only prolong life. The virus and the disease destroy the body's defenses and induce fatal forms of various cancers. The virus is spread by direct contact with other cats. Therefore a cat that goes out and can meet other cats is at risk.
  • There is another related virus, also from the 'retrovirus family', the F.I.V. (for Feline Immunodeficiency Virus) for which there is no recognized effective vaccine. FIV is sometimes called 'cat AIDS' by analogy to HIV (Human Immunodeficiency Virus) responsible for AIDS in humans. However, it must be emphasized that these are two very distinct viruses and that transmission is not possible.

Chlamydia

  • This is a bacterial disease that causes inflammation of the conjunctiva (conjunctivitis) and ulcers and discharge from the eyes. The organism can also cause infertility in some cats. Kittens affected by the disease may exhibit runny eyes for several weeks. Contagion is strong in catteries or in homes where there are many cats. The disease tends to recur. Treatment requires antibiotics for several weeks. The chlamydia vaccine is now often given at the same time as the core vaccines.

Rabies

  • Vaccination is required in many countries and regions because of the risk of contamination of this horrible deadly disease in humans. Vaccination, on the other hand, is unnecessary in rabies-free countries, such as the United Kingdom, Australia, Japan and others. However, vaccination in these countries is authorized and even required when traveling to countries affected by rabies. If you plan to travel with your pet, ask your veterinarian about vaccination requirements. Similarly, if your cat accompanies you to holiday camp or camping, rabies vaccination will often be required.

When should you vaccinate your cat?

Kittens are protected from infectious diseases by antibodies received from the mother through breast milk or colostrum (called maternal antibodies) in the first hours of life. Vaccines given too early have no effect because maternal antibodies will prevent the vaccine from producing antibodies.

Animation illustrating maternal antibody interference:

However, around the age of 7 weeks, the immunity associated with maternal antibodies fades and vaccination will then be useful. Some kittens have not received sufficient maternal protection (no or little milk for example) and in some cases will benefit from early vaccination. As a general rule, the first injections are suggested between 7 and 9 weeks and a second vaccine is useful 3 to 4 weeks later.

Animation illustrating the vaccine protocol with 2 injections:

If the vaccines are administered early and if the risk of contamination is great, it may happen that three injections are prescribed for what is called the "first-vaccination".

Animation illustrating the need for 3 injections:

Follow the recommendations of your veterinarian who will give you the schedule of vaccines to administer as well as useful boosters.

Why are vaccine boosters needed?

Most vaccines require two injections 3 weeks apart. It is the second injection that will stimulate lasting antibody production, usually for several months. But antibodies fade over time and at different rates in different vaccines. The most common diseases in your area will cause your veterinarian to recommend boosters for some rather than others. As well as there are generalities, take into account the recommendations of your veterinarian which will be specific to your cat and its lifestyle, but also to the environment and the risks of certain diseases in your region.

Animation illustrating the need for a booster shot:

If your cat has not been vaccinated for several years, your veterinarian will probably recommend that you repeat a first vaccination protocol (two injections 3 weeks apart) rather than a simgle booster. It is important to respect the booster schedule in order to guarantee vaccine protection. Some catteries will be particularly strict and will not accept boarding your cat if it has not been properly vaccinated.

How often should we vaccinate?

Vaccine protection is not necessarily for life. The duration of the immunity provided by the vaccine depends on the circumstances and the individuals, but also on the types of vaccines used. Vaccine brands, valances and vaccine types (killed or live) play a role. Once again, your veterinarian is in the best position to guide you and select the rate of useful vaccinations. It is often during an annual check-up that the veterinarian recommends the vaccines that will be useful for the period.

Are vaccines still effective?

The quality of vaccines used today is excellent, but occasionally an individual may not be fully protected by a vaccine. This is sometimes because the cat was already sick at the time of the vaccine, or it was stressed and its immune system was not functioning normally. Your veterinarian will examine your cat before vaccinating it and any abnormal signs will be a possible reason for postponing the vaccination.

Can a vaccine be dangerous?

Your cat may be a bit "smeared" for a few hours, or a day or two, following the vaccination. The injection site may also be painful for a few days. These are fairly rare but possible side effects. If these symptoms should be prolonged or worsen, it will be appropriate to return to see your veterinarian.

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