Just as in humans, vaccinating your cat helps to protect him or her against several serious and/or life-threatening diseases.
Anyone who cares for his or her cat will want to protect it in this way and vaccination is a critical part of a proper preventive healthcare programme.
A vaccine is usually given by an injection under the skin, although sometimes may be given as drops into the eyes or nose. It is a preparation designed to provide protection against a specific infectious disease through stimulating an immune response that will protect the cat if it is subsequently exposed to the infection.
Vaccinations may contain:
Live organisms (so-called ‘modified live vaccines’) where the organism has been modified so that it will not cause disease but can replicate for short a time after the vaccine has been administered to provoke a good immune response
Killed organisms (killed or inactivated vaccines) where the organism has been killed and is then generally combined with other agents/chemicals to help provoke a good immune response
Recombinant vaccines – this is a newer type of vaccine where parts of one organism (the genes responsible for producing proteins important in provoking a good immune response) may be incorporated into another organism, which may then be used to vaccinate a cat
All vaccines have to undergo rigorous safety and efficacy testing before they are licensed for use in cats by regulatory authorities. When used appropriately and as recommended they are both safe and provide crucial protection for cats against a number of diseases.
Some people are tempted to use ‘homoeopathic vaccines’ or may have these recommended by a friend. However, these should never be used – they have no scientific basis and cannot provoke the specific immune response that is needed to provide protection. Only use vaccines that are recommended by your vet.
What diseases can and should I vaccinate my cat against?
The availability of different vaccines will vary between different countries, because some diseases are not present everywhere, and because vaccines are not necessarily licensed (and therefore available) in every country.
The most commonly available vaccines are used to provide protection against the following infections:
Feline panleukopenia virus (FPV, feline infectious enteritis; feline parvovirus)
Feline herpesvirus (FHV-1, cat flu)
Feline calicivirus (FCV, cat flu)
Feline leukaemia virus (FeLV)
Core and non-core vaccines
Vaccines can be divided into core vaccines and non-core vaccines. The core vaccines are considered essential for all cats (including indoor-only cats) because of the widespread and/or severe nature of the diseases being protected against. Non-core vaccines are only given to cats if there is a genuine risk of exposure to the infection and if vaccination would provide good protection. Decisions regarding the requirement for non-core vaccines may be based on the cat’s age, lifestyle and contact with other cats. You should always discuss with your vet what vaccines your own cat may require.
Feline panleucopenia virus (also known as feline parvovirus or feline infectious enteritis) is a severe and frequently fatal cause of haemorrhagic gastroenteritis. Outbreaks of infection with this virus are common and a high proportion of affected cats can die.
Vaccination against this virus is highly effective and has a critical role in protecting cats against infection, especially as the virus is highly contagious. The virus can also survive for long periods in the environment so vaccination is the only real way to protect cats.
Feline herpes virus and feline calicivirus
Vaccines for feline herpes virus (FHV-1) and feline calicivirus (FCV) are always combined, as these two viruses together are the main causes of upper respiratory tract infections in cats (cat flu).
Affected cats typically show sneezing, nasal discharge, conjunctivitis, eye discharge, and mouth ulcers. Clinical signs vary from mild to extremely severe, and occasionally other complications may develop including viral pneumonia. With FHV-1, even after the initial signs subside, most cats will remain permanently infected with the virus and some go on to develop recurrent eye infections or other signs.
The viruses are often transmitted by direct or close contact between cats (eg, in sneezed droplets), but they may also survive for short periods in the environment.
Both of these viruses are ubiquitous in cat populations, and because infection is so common, and can often be quite severe (especially in younger cats), vaccination is considered important for all cats. Although vaccination does not always prevent infection with these viruses, it will help greatly in reducing the severity of disease if a vaccinated cat does become infected.
See feline herpes virus and feline calicivirus
Rabies is an important disease and although it is more common in dogs (and more commonly passed from dogs to humans than cats to humans) cats can be infected and can be a source of human infection.
For these reasons, where rabies is present in a country or in a region, it is recommended that all cats should be vaccinated against this disease. Vaccination is very effective in preventing disease.
Other vaccines are regarded as ‘non-core’ and used when vaccination would provide valuable protection for an individual cat.
Feline leukaemia virus (FeLV)
FeLV is an important disease that can be spread through fighting, through mutual grooming, and through sharing of food/water bowls and litter trays. Kittens may also acquire infections from the queen before birth.
FeLV is an important disease, causing a wide variety of problems in persistently infected cats including immunosuppression, anaemia, and lymphoma. Most persistently infected cats will die as a result of their infection.
It is possible to perform blood tests to identify cats that are infected with this virus, and isolating such cats and preventing them from coming into contact with others is one way of preventing infection. A number of FeLV vaccines are also available and are effective in protecting cats. Generally, cats that go outside and may come across other cats of unknown status may be at risk of being exposed to FeLV, and vaccinating such cats may be very valuable (although the risks will vary between different regions). It has also been strongly recommended that all kittens are vaccinated against FeLV on the basis that younger cats are more susceptible to this infection and it cannot usually be predicted what the risks for the cat would be as it grows up.
For further information on FeLV, see Feline leukaemia virus
Chlamydophila felis is a type of bacteria that mainly causes conjunctivitis in cats. Young kittens in multicat households (eg, breeding households) are most likely to be affected and there may also be mild upper respiratory signs.
Affected cats can be treated successfully with appropriate antibiotics, but vaccination may be helpful in some circumstances as part of a control programme in an infected household
For further information on Chlamydophila felis, see Chlamydophila felis infection in cats
Bordetella bronchiseptica is another bacterial infection that can be a part of the upper respiratory infection complex (cat flu) in cats. It is not as common as FHV-1 or FCV (see above), but can sometimes be a problem especially in stressed cats and cats from large colonies. The bacterium can also be an occasional cause of pneumonia in young kittens.
Cats with Bordetella bronchispetica can be treated effectively with appropriate antibiotics, and vaccination is not required in most cats. However, in colonies of cats with repeated outbreaks of disease, vaccination may play a role in helping protect cats.
Feline immunodeficiency virus
Feline immunodeficiency virus (FIV) vaccination is available in some, but not all counties. This virus is quite common among cats, especially cats that go outdoors and are involved in fighting (infection is mainly spread through cat bites).
There are many different strains of the FIV virus and it is not entirely clear as of yet how well the available vaccine protects against all these different strains, but studies suggest that it is able to provide a valuable degree of protection for cats at risk of exposure. A potential problem is that vaccinated cats will also test positive on the routine tests used to detect FIV-infected cats, but newer diagnostic assays are becoming available that may overcome this problem.
For further information on FIV, see Feline immunodeficiency virus
How frequently should my cat be vaccinated?
All kittens should receive their core vaccinations and any others that are agreed between you and your vet. The initial vaccine course is often started at 8-9 weeks of age, with a second injection 3-4 weeks later. It is now common also to recommend a third vaccination (especially for FPV) at 16-20 weeks of age to ensure the kitten is properly protected.
A first booster vaccination should be given 12 months later to ensure a good level of continuing protection. However, after that, the frequency of booster vaccinations may be only every 1-3 years depending on the vaccine, disease and risk of with the individual cat.
Cats that stay at a boarding cattery will generally require an annual vaccination (or booster vaccine before the cat goes into the cattery) as this is a higher risk situation.
What problems may be associated with vaccination?
Adverse effects from vaccines are very rare, especially in view of the millions of doses that are administered every year. The most common side effects are mild and include lethargy, inappetence or tenderness at the injection site, usually lasting no longer than a few days. More marked side effects may include vomiting, diarrhoea, lameness, fever, signs of respiratory tract infection, or lumps at the site of injection.
The side effect that has received the most attention in recent years is fibrosarcoma – this is a type of malignant tumour that can develop at the site of vaccination. It is now well recognised that this is a very rare occurrence (probably less than 1 in 20,000 vaccines administered) and it seems that both vaccines and other injectable products can carry a small risk of inducing this in cats. Because of this, after your cat receives any vaccine, it is sensible to monitor the injection site regularly and if a swelling at the site persists for several weeks and/or continues to enlarge, get it checked immediately by your vet.
Because fibrosarcomas can be very difficult to completely remove by surgery, it has been recommended by groups in the USA that rabies vaccines are given in the right hind leg, FeLV vaccines in the left hind leg and FHV-1/FCV vaccines in the right front leg. This is partly because, should a fibrosarcoma develop at these sites, limb amputation is possible and offers a better chance of complete removal than trying to remove an invasive tumour from the neck region.
A number of other vaccines may be available in certain countries but not others. The effectiveness of these vaccines should be evaluated carefully, and none of these should be regarded as ‘core’ (or essential) vaccines. Some that may be available include:
Feline infectious peritonitis
Vaccination is generally a very safe procedure that has substantially reduced the impact of several very serious diseases. However, as with any other product, no vaccine can ever be entirely without side effects so it is important to carefully choose which vaccines are necessary for any individual cat and to evaluate how frequently they should be given. You can discuss all these issues with your vet.