Vaccinations

A vaccine is a veterinary product that trains the immune system to recognize and destroy viruses or bacteria without the animal developing the actual disease. There are several types of vaccines (live, inactivated, recombinant, and others).

It's important to understand: a vaccine doesn't treat a disease. It prepares the body in advance for an encounter with an infection.

After a vaccine is administered, several stages take place.

1. The immune system meets the pathogen. The body recognizes that a “foreign” agent has appeared. Although the real virus doesn't cause disease (or may not even be present at all), the immune system reacts as if a real infection had occurred.

2. Antibody production begins. The body produces special proteins called antibodies. These are what can quickly recognize the real virus and neutralize it.

3. Memory cells form. This is the most important stage. The immune system remembers: what the virus looks like; how to destroy it quickly; which antibodies are needed specifically against it. This memory can last for several years, and sometimes almost a lifetime, depending on the disease.

4. When a real infection occurs, the immune system recognizes the virus almost instantly, antibodies are produced very quickly, and the virus doesn't have time to multiply much. As a result, three outcomes are possible: the cat doesn't get sick at all; the illness passes very mildly; the risk of death drops by tens of times.

Many viral diseases in cats are practically untreatable. For example: panleukopenia; rabies; some forms of viral leukemia.

A veterinarian can only treat the consequences: dehydration; inflammation; secondary infections; seizures; breathing problems.

The body itself must defeat the virus on its own. If the immune system hasn't been trained in advance, the chances are significantly lower.

Building a full immune response takes time. The body usually needs 2 to 4 weeks after vaccination to produce enough antibodies and memory cells. During this period, the animal is still vulnerable.

Typically: the first antibodies appear after 5-7 days; solid protection forms after 2-4 weeks.

All cat vaccines are conventionally divided into two large groups.

Core vaccines are recommended for all cats, regardless of age, breed, or lifestyle — even if the animal never goes outside. The reason is simple: pathogens can be brought into the home on shoes, clothing, hands, or objects.

1. Panleukopenia (Feline Panleukopenia Virus, FPV). The most dangerous viral disease in cats. Also known as feline distemper or infectious enteritis. It affects the intestines, bone marrow, and immune system. Mortality in kittens can reach 90%. The virus is very resistant and can survive in the environment for more than a year.

2. Feline herpesvirus (FHV-1). Causes viral rhinotracheitis. Main symptoms: runny nose, eye ulcers, conjunctivitis, sneezing, coughing, difficulty breathing. After recovery, the virus remains in the body for life, and the disease can return during periods of stress.

3. Calicivirus (FCV). A very common virus. Causes mouth ulcers, tongue inflammation, high fever, runny nose, lameness, and sometimes severe pneumonia. There are many strains of the virus, so a vaccinated cat can sometimes still get sick, but the illness is much milder.

4. Rabies. Almost always fatal once symptoms appear, and dangerous not only to animals but also to humans. In many countries the vaccine is required by law, especially if the cat travels, goes outdoors, participates in shows, or crosses national borders.

These vaccines are given only when risk factors are present.

1) Feline leukemia (FeLV). A very serious viral disease. Affects the immune system, bone marrow, and blood. Increases the risk of tumors, severe infections, and anemia. The vaccine is recommended for kittens, cats with outdoor access, and animals that come into contact with other cats.

2) Chlamydiosis (Chlamydia felis). A bacterial infection causing severe conjunctivitis, eye discharge, and inflammation of the respiratory tract. Usually given in catteries, shelters, and homes with many cats.

3) Bordetella bronchiseptica. Causes upper respiratory infections, more common in shelters, boarding facilities, and catteries. Most house cats don't need this vaccine.

4) FIV (feline immunodeficiency virus). A vaccine exists in some countries, but it is used on a limited basis, doesn't provide full protection, and can complicate diagnosis of the disease.

5) FIP (feline infectious peritonitis). An intranasal vaccine against feline coronavirus exists, but its effectiveness is considered insufficiently proven.

For a cat that lives exclusively indoors, the following are usually recommended: panleukopenia, herpesvirus, calicivirus. Rabies — depending on legal requirements, travel, and your veterinarian's recommendations. FeLV usually isn't required if the cat doesn't have contact with other animals.

This has to do with maternal antibodies. In the first weeks of life, a kitten receives protection through its mother's milk. These antibodies protect the kitten, but they also interfere with the vaccine's ability to work.

If vaccinated too early, maternal antibodies will destroy the vaccine. If vaccinated too late, maternal protection will already be gone while the kitten's own immunity isn't yet established.

That's why vaccination is given as a series: 8 weeks; 12 weeks; sometimes 16 weeks. This practically guarantees a moment when the vaccine can “teach” the immune system.

Immune memory gradually weakens. Antibody levels decrease, and memory cells work less effectively. Over time, protection drops to the point where the body once again becomes susceptible to infection. This is why most vaccines require repeated doses.

Yes, no vaccine offers a 100% guarantee. However, a vaccinated cat will go through the illness much more easily, without serious complications and with minimal risk to life. The goal of vaccination is to reduce the severity of disease and prevent fatal outcomes.

Modern vaccine products undergo strict quality control and are highly purified. Side effects are possible (lethargy, a slight fever), but they are rare and pass quickly.

The risk of severe complications after vaccination is a fraction of a percent. Meanwhile, the risk of death from certain infections reaches: 50-90% for panleukopenia; nearly 100% for rabies once symptoms appear. This is exactly why veterinary organizations around the world consider vaccination one of the most effective measures for protecting cats' health.

Revaccination is the repeated administration of a vaccine after the initial vaccination, to maintain immune protection.

Primary kitten vaccination: 8-9 weeks — first vaccine against panleukopenia, herpesvirus, and calicivirus; 12 weeks — second dose; 16 weeks — a third dose may be needed if vaccination started early; 12-16 weeks — first rabies vaccine; 12 months after completing the primary course — first revaccination.

Adult cats: panleukopenia (FPV) — immunity lasts a long time, revaccinate every 3 years; herpesvirus (FHV-1) and calicivirus (FCV) — annually if risk is high, every 3 years if risk is low; rabies — the interval depends on the vaccine and national law (1 or 3 years); FeLV — annually if the risk of infection persists.

Kittens: the highest risk of severe infections — vaccination is especially important.

Adult cats (1-7 years): with timely vaccination, immunity is usually well maintained.

Senior cats (over 10-12 years): age by itself isn't a reason to skip vaccination, but a clinical exam is done before the shot.

A veterinarian may recommend an individualized schedule if the cat: roams freely outdoors; lives in a cattery or shelter; travels frequently; has chronic illnesses; has an immune deficiency; is being treated with immunosuppressive drugs; is pregnant or nursing kittens.

In most cases — yes. Even though some vaccines are given only once every three years, regular revaccination remains an important part of prevention. Protection doesn't become “permanent” with age, so at every annual checkup the veterinarian assesses the cat's health, infection risk, and determines which vaccines truly need to be updated that year.