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Do I have to vaccinate my cat?

There's only one answer to this question: Yes, you have to - peroid!! By vaccinating your cat regularly, you're not only protecting your cat's life, you're also protecting other felines who may possibly come in contact with yours. Even indoor cats should be vaccinated against some viral diseases, as these viruses can be brought into the house by you, on your shoes or clothes.

Unfortunately, many people do not seem to be interested in vaccinating their cats and these peoples' pets aren't vaccinated at all or only sporadically. They would be like: "...too expensive, vets and pharmaceutical industry only want to make money, my cat doesn't need vaccination, it's healthy..." - an irresponsible carelessness which could cost your cat's and other cats' lives.

Please realize that in a well-vaccinated cat population the chances for outbreaks of viral diseases are drastically reduced. Think about smallpox or measles: Those diseases which have been a severe threat to a human's life in earlier times, have been dammed up to the greatest possible extent in the developed nations by regular vaccination. Now that people got more careless about vaccination, new outbreaks of these diseases do sporadically occur. Here you can see how important it is that a certain percentage of a population is sufficiently vaccinated. It's the same with cats. Viral diseases are the most common cause of death in cats.

Therefore it is important to have you cats vaccinated, regularly and right from the start! With most vaccines, the initial immunization starts at the age of eight weeks, followed by a second shot at the age of twelve weeks, plus another one twelve months later. The vaccine against rabies is an exception, it shouldn't be given before the kitten is twelve weeks old. Depending on wether a cat will be kept indoors or outdoors, you have to decide which vaccinations should be continually given.

Here follows a summary of the most common viral diseases in cats and the corresponding vaccination:

Respiratory Viral Diseases Panleukopenia Feline Leukemia
Rabies FIP FIV

Respiratory Viral Diseases (Upper Respiratory Infection, URI, "Cat Flu")

URI is a febrile infection of the upper respiratory system, caused by the calici virus, the herpes virus or the bacterium chlamydia. The symptoms are watery eyes and a runny nose; if untreated, a purulent discharge and bloody ulcers in nose and mouth will follow. This state can become life-threatening to the cat since it will stop eating and drinking due to a reduced sense of smell.

Each cat should be vaccinated against URI, even indoor cats. The transmission of the calici virus does not only occur by direct contact from cat to cat but also from viruses brought into the house by humans, carried on clothes and shoes. Initial immunization should be be started at the age of eight and twelve weeks, then annually (indoor cats that do not have any contact with other cats: every three years).

Panleukopenia (Feline Infectious Enteritis, "Feline Distemper")

It's the same as with Respiratory Viral Diseases: Humans may carry the virus with them on their shoes and clothes and bring them into the house, so each cat should be vaccinated against panleukopenia, also those who are kept strictly indoors! There is a combined vaccine for both panleukopenia and URI available in Germany, and vets often use that one.

Panleukopenia is caused by the parvo virus. This virus is extremely resistant to disinfectants and can survive outside its host's body for up to a year or even longer. Animal shelters often have to cope with severe outbreaks; once you've got that virus in your house, it's hard to get rid of it. Therefore regular vaccination is a must (outdoor cats annually, indoor cats without any contact to other cats every three years).

Panleukopenia is fatal in many cases, especially for kittens. First lethargy and a loss of appetite will occur, and it won't take long until it comes to fever, vomiting and diarrhea. In extreme cases, death comes within a couple of hours. Therefore the cat should be brought to the vet as soon as it's showing the first symptoms.

Cats that have survived a panleukopenia infection will most likely become chronic carriers, shed the virus and infect unprotected cats. Females who were exposed to the parvo virus during pregnancy (this goes also for the vaccine, so never vaccinate a cat while it's pregnant or breast-feeding!) often give birth to kittens with cerebellar ataxia, a movement disorder being caused by a damage of the central nervous system.

Feline Leukemia (FeLV)

Feline leukemia is a very wide-spread viral disease; surveys say that almost every 6th case of death in cats is caused by an infection with the feline leukemia virus (FeLV), a retrovirus. It is estimated that 75% of all cats will be exposed to the virus at least once in their lives.

Feline leukemia is treacherous since a cat can carry the virus for many years before it comes to an outbreak. The cat may appear healthy during that period of time, or it's just that the immune system seems to be a little weak. But once the disease has broken out, it is fatal.

In many cases, the disease isn't easy to diagnose. The cat is lethargic and has a fever, and you may notice pale gums and mucous membranes. Inflammated gums and eczema may occur. There can be tumors in thorax and abdomen. Often feline leukemia leads to further diseases which are caused by a weak immune system, such as FIP.

The vaccine against feline leukemia has been discussed lately since it has been associated with cases of so-called injection-site-sarcoma, some kind of fibrosarcoma occuring in the punctured area. There's no doubt that this is something to keep in mind, but in my opinion you should balance the risks. An outdoor cat, or a cat that's in contact with other cats (may it be at cat shows or in a cat hotel) should definitely be vaccinated against feline leukemia. It's mostly transmitted directly from cat to cat; outside the body the virus cannot survive. According to this, indoor cats without any other feline contacts are not at risk. But personally I think that it's better to at least initially immunize an indoor cat. The first vaccination can be given at the age of eight weeks, followed by a second vaccination four weeks later. A blood test for FeLV is always required before the initial immunization can be given.

The feline leukemia vaccine is also available in combination with the URI and panleukopenia vaccines, it's less expensive that way.

Attention: I've noticed that the leukemia vaccination is not a standard vaccination in some vet's offices in Germany. Ask your vet about it and - if necessary - check your cat's certificate of vaccination.


Rabies is a notifiable disease in Germany since it can be transmitted to humans. In most cases it will be transmitted by wild animals, such as foxes, but every outdoor cat is potentionally at risk. Even thought Germany has been declared rabies-free in 2008, there are still reported cases of rabies in dogs that were brought into the country from abroad. Rabies is transmitted by bites. The virus affects the brain of the infected animal and leads to erratic behavior, aggression, paralysis and death. In Germany it is prohibited to treat animals infected with rabies, every animal suspected to be infected will be euthanized.

Important: It's regulated by the German law that every unvaccinated animal which might have been in contact with an animal infected with rabies has to be euthanized! For this reason, is it of great importance that every outdoor cat is protected by vaccination, and that you can prove this with the cat's certificate of vaccination (the last vaccination must be at least four weeks ago and not longer than a year; you cannot vaccinate a kitten that's younger than twelve weeks). The rabies vaccine has also been discussed in association with a possible fibrosarcoma risk, but please don't take the risk of exposing an outdoor cat to the dangers of a possible rabies infection respectively of being euthanized by the authorities!

FIP (Feline Infectious Peritonitis)

Another very treacherous viral disease is the feline infectious peritonitis. It's caused by a mutated form of the feline corona virus (FCoV - not to be confused with SARS-CoV-2 which caused the current Covid-19 pandemic!!), and it is - once broken out - always fatal*. There are two forms of FIP: the wet form and the dry form. The wet one is easier to diagnose because of the abdominal dropsy (ascites) which is giving an FIP cat its typical look. The cat looks skinny but has a big, balloon-sized belly. There can also be liquid in the thorax, and inflammation of the inner organs can occur. Jaundice is very common in FIP cats. The ascites does not occur in the dry form, so the diagnose is way harder to make. Besides, to be 100% sure about FIP, an autopsy needs to be done since there are no reliable blood tests.

A blood test can only show an infection with a corona virus, a high titer is considered to be an indicator for FIP. However, this test is not very reliable.

Corona virus infections do often occur in cats and you won't even notice. They may have caused a cold or diarrhea in kittens. Usually these infections are harmless and the cat recovers, but even though the immune system has produced anti bodies against the virus, it may permanently remain in the intestines and be shed with the feces.

Under certain circumstances it may happen that this harmless, so-called feline enteric corona virus (FECV) mutates to the form that causes FIP: FIPV. It is esteemated that about 5 - 10% of all FECV-carriers may later develop FIP. The mutation factors can be stress, a weak immune system (maybe if there's a leukemia-infection already), or too many cats in one place. For this reason, breeders often have to deal with FIP in their cattery. The disease is transmitted directly (or via the feces of infected cats; therefore, litterboxes are considered to be the main source of infection), or by spontaneous mutation. Outside the cat's body the virus can survive several weeks or even months.

There's a vaccine available against FIP which will be dropped into the cat's nose, but it is very controversial. This vaccine is considered to give a protection of about only 60%. Besides, there were some concerns in the past that this vaccine (a genetically modified and thermolabile form of the virus) may even cause an FIP outbreak when there's already a corona virus in the cat's system. This has apparently been denied by now, but another problem is that you must not vaccinate a kitten younger than 16 weeks while most FECV infections already occured before the kitten has reached the age of 6 weeks. For this reason I have decided to not vaccinate my cats against FIP. Breeders, on the other hand, should balance the risk here and maybe ask their vet for advice.

* Lately, there have been reports of cats being treated successfully with a med called GS 441524. Unfortunately, this drug is not yet approved in Germany (where I live). I hope this will change very soon!

FIV (Feline Immunodeficiency, "Cat AIDS)

Along with leukemia, FIV is another immunodeficiency disease, similar to HIV (AIDS) in humans. It is caused by the feline immunodeficiency virus (FIV). The symptoms are unspecific and resemble those of the feline leukemia.

In Germany, there's no vaccine available at this point, but you can make some arrangements to protect your cat: The virus is mostly transmitted by bites, as they occur from territorial fighting or mating. So keeping your cat strictly indoors is a very reliable protection against an infection. If the cat is an outdoor cat, spaying or neutering will reduce the risk a bit since neutered and spayed cats won't date and won't get involved into cat fights that much (please read also: She's gotta have kittens?).

And here's all the information summed up:

Respiratory Viral Diseases at the age of 8 weeks vaccination important, also for indoor cats!
Panleukopenia at the age of 8 weeks vaccination important, also for indoor cats!
Feline Leukemia at the age of 8 weeks according to the circumstances, for outdoor cats a must!
Rabies at the age of 12 weeks according to the circumstances, for outdoor cats a must!
FIP at the age of 16 weeks vaccine is controversial; recommended for breeders
FIV --- no vaccine available!

By the way, if you have planned to adopt a cat and there are already cats living in your household, please make sure that the new cat has been tested and vaccinated. Of course the resident cat should also be vaccinated to be protected against a possible infection.