cat unwell after vaccination
Cat Health and Wellness

Can Cats Have a Reaction to Vaccinations?

Vaccines are necessary for most cats, especially those who spend much of their time outdoors. Although the experience is never pleasant, felines must be vaccinated against rabies by law. Also, other vaccinations are highly recommended to protect your cat against infectious diseases.

Do cats feel bad after vaccinations? All vaccines can cause side effects in cats. Fever, lethargy, reduced appetite, and swelling are all common. Some cats also have trouble walking and experience stomach upsets. These adverse effects should subside after a day or two. If weeks pass and your cat is not feeling well, seek advice from a vet.

There is always risk involved in vaccinating a cat. These dangers alone are not enough to ignore feline vaccinations, though. Vaccination may save your cat’s life. You’ll need to make an informed decision about whether to vaccinate your cat based upon all the available evidence.

Types of Vaccinations for Cats

A vet will offer many vaccinations for your cat. These protect against the following conditions:

  • Rabies
  • Feline Distemper (aka Panleukopenia), Feline Herpesvirus (FHV-1), and Feline Calicivirus (FCV)
  • These three vaccines are combined into one, known as the FVCRP vaccine
  • Feline Leukemia Virus (FeLV)
  • Feline Immunodeficiency Virus (FIV)
  • Feline Infectious Peritonitis (FIP)
  • Bordetella
  • Chlamydophila felis
  • Feline

Of these vaccines, rabies is the only one that is required by law in most states. Check the status of your state using this table compiled by the American Veterinary Medical Association.

Even if you reside in a state that doesn’t mandate rabies shots by law, it remains advisable. The disease is commutable among animals and humans.

The American Association of Feline Practitioners also considers the FVCRP to be a core vaccine. Beyond this, vaccines are optional.

How are Vaccines Administered to Cats?

Feline vaccinations are commonly administered by injection. The location of the shot is typically behind the legs. Previously, many vets chose to administer shots to the neck. This is due to the flexibility of the skin in this area. It’s easier to stretch the skin, and administer a shot.

cat limping after vaccination

In recent years, the risk of Feline Injection Site Sarcoma (FISS) has become increasingly prominent. This means the neck is best avoided. FISS involves a cancerous tumor at the site of vaccination.

This tumor would need to be removed if it arises. That can be difficult, and almost impossible around the neck. As a result, most vaccinations are now injected around the leg.

Vaccinations are usually given in the following locations:

  • Rabies – right back leg
  • Feline Leukemia Virus – the left hind leg
  • FVCRP – right front leg

The logic behind this thinking is preparing for the worst. If a cat does develop a malignant tumor at the injection site, amputation may be necessary.

Not all vaccines must be injected. FVCRP, FIP, and Bordetella can be inhaled nasally, but may not be as effective as injections. Discuss the options with a vet.

If your cat takes their vaccinations intranasally, she will sneeze and sniff for a while afterward. This is natural and nothing to worry about. Some streaming from the eyes and nose may also follow.

Common Side Effects of Cat Vaccinations

Vaccines are medication, and all medication carries potential side effects. It’s to be expected that your cat may feel unwell after vaccination.

A cat’s immune system starts to adapt following a vaccine. This will mean that they seem under the weather. This is only a concern if they do not quickly recover. Some of the most common side effects of feline vaccination include:

  • Fever
  • Lethargy and generally low energy levels
  • Lack of appetite
  • Vomiting and diarrhea
  • Swelling around the location of the injection
  • Trouble walking

These side effects should be very short-term. If your cat is still struggling 48 hours after her vaccination, take her to see a vet.

My Cat is Limping After a Vaccination

As vaccinations are injected into a cat’s leg, some limited mobility is to be expected. Your cat may experience a small amount of swelling at the injection site. This will make it tougher to move.

The FVCRP vaccine is most likely to cause limping. This is because lameness is a common symptom of feline calicivirus. This is so common that it is called limping syndrome.

Limping syndrome is a temporary problem. Cats that struggle with this side effect bounce back as quickly as they experienced the issue.

Cats that have this vaccination often experience their joints stiffening. This will naturally make them a little more lethargic. Any movement will be painful for the duration of this side effect.

Your vet may prescribe a painkiller for your cat following their vaccination. This will be safe. Never offer your cat human medication, though.

Pay particular attention if your cat can’t walk after vaccination. Any vaccine can cause some degree of limited mobility. Only the calicivirus vaccine should cause ‘limping syndrome.’

If your cat is limping for more than a day or two, seek medical help. This suggests a more troubling reaction to a vaccination. Such instances are rare, though.

My Cat is Vomiting After a Vaccination

Vomiting should be monitored after vaccinations. It is not unheard of, but neither is it entirely commonplace.

On the one hand, your cat may just be vomiting her previous meal. A cat’s body will undergo a jolt after a vaccine. That can upset her stomach and cause vomiting.

cat not feeling well after vaccinations

Diarrhea is also possible for the same reasons. However, it’s also possible that your cat is struggling with an allergic reaction to the vaccine.

Cats tend to vomit at the drop of a hat, and there could be any number of explanations. Do not immediately panic if your pet is sick after vaccination. However, a cat vomiting for 24 hours straight should always be checked over by a professional.

My Cat Has No Energy After a Vaccination

It’s natural for a cat to become listless and sleepy after her vaccines. If you have ever had a flu shot and felt lousy afterward, you’ll know how it feels.

A feline that has been vaccinated will likely want to be left alone to sleep. She may also run a high fever. Leave your cat alone in such an instance as she needs to rest.

Set your pet up with their favorite bed and blanket in a quiet location. Fill the room with food and water, just in case. Also provide a scratching post, just in case your cat has a sudden burst of energy.

Above all, you need to ensure that your cat is left alone. Tell any children in the home not to disturb her. She should be treated as if she has a minor cold.

After 24 hours, your cat will likely be back to her old, playful self. If not, give her an extra day. Remember, her immune system has been given a jolt, and that can be very tiring.

My Cat is Not Eating After a Vaccination

Any cat that has not eaten for 24 hours is a cause for concern. Cats have small bodies and few fat reserves. A loss of appetite is a common side effect of vaccination.

Assess whether your cat isn’t eating or is just reluctant to walk to her bowl. If your cat has little energy or limping syndrome, that can feel like a long journey.

cat not eating after vaccination

Carry your cat’s food to her and let her enjoy breakfast in bed. She may still refuse food as she’s not hungry. This will at least give her an option, though.

My Cat Has a Lump at the Site of Their Vaccination

The most alarming reaction to vaccination is Feline Injection Site Sarcoma (FISS). This is a cancerous tumor that develops following inflammation around the site of the injection.

A vet must assess a cat with a substantial lump that persists days or weeks after vaccination. Another sign of FISS includes the lump exceeding 2cm in diameter, especially if it keeps growing.

If the sarcoma that is caused by vaccination is not treated, it will grow. This, in turn, will allow cancerous cells to spread throughout her body. The lungs and other internal organs will quickly be affected. This will be lethal to any cat.

It is not entirely clear why cats experience FISS. Some experts believe that the felines already have tumors. The inflammation caused by the vaccination activates the malignant tumor and causes it to spread.

If you present your cat to a vet with FISS, urgent surgery will be required to remove the tumor. Time is of the essence here. The sooner your cat is seen, the sooner the operation can take place.

Based on her unique case, your cat may also need to undergo radiotherapy or chemotherapy. As discussed, amputation may also be a requirement.

What is certain is that your pet will need to be treated as a matter of urgency. This means that it’s advisable to open a pet insurance policy before having your cat vaccinated.

FISS remains rare. The journal Acta Veterinaria Scandinavica claims that instances remain as low as 1 in 10,000. All the same, be vigilant about observing any symptoms.

Can Cats Be Allergic to Vaccines?

It’s rare, but it’s possible for a cat to have an allergic reaction to a vaccination. Cats can be allergic to anything. They could even react to the rubber gloves that your vet wears to administer the vaccine.

An allergic reaction is more concerning than a typical reaction to a vaccine. Signs that your cat is allergic to the vaccination include:

  • Hives breaking out on the skin
  • Swelling around the face, eyes, mouth, and neck
  • Trouble breathing
  • A sharp drop in body temperature, especially around the tail and paws
  • Low blood pressure and decreased heart rate
  • Seizures and collapse

These reactions will be treated with steroids or antihistamines. These reduce the ill-effects of the allergy. In more severe cases, your cat may require intravenous fluids and further observation.

If you call in advance, your vet may be able to offer first aid advice. The over-the-counter remedy Benadryl, for example, is safe for cats in appropriate doses. Never administer this without a professional’s say-so, however.

Can I Check if My Cat is Allergic to Vaccines in Advance?

As felines receive their first vaccinations as kittens, there is rarely time to check for allergies. This means that most of these reactions are discovered on a trial-and-error basis.

If you adopt an adult cat, check her medical records. This will specify any allergies she may have. It will also have been noted if she has reacted poorly to vaccines in the past.

If you cannot gain access to this information, have your cat assessed before vaccinating. This will be more expensive, but better than dealing with an allergic reaction after the event.

Cat Personality Changes After Vaccination

Some cats are never quite the same after vaccination. It’s extremely rare, but it does happen. This is because the vaccine causes a chemical reaction in her brain.

Expect this for around 48 hours. Your cat may be a little crankier than usual, and maybe even aggressive. This is because she is feeling sore. It will pass, though.

cat vomiting after vaccination

If your cat seems to have undergone a complete transformation, seek further guidance from a vet. Make a note of all the changes to your cat’s behavior and look for a pattern. If a vet cannot help, consider consulting a feline behaviorist.

Vaccinations can be scary for cats. Most pets are fearful of the vet. When they’re prodded and poked with needles, this magnifies the anxiety. Your cat doesn’t understand that it’s all in a good cause.

It’s possible that your cat has been traumatized by her vaccination. If so, she’ll need more help than you can provide. With the right advice, you can do what is necessary to help your cat.

How to Make a Cat Feel Better After Vaccines

If your cat is unwell after her vaccinations, she’ll need some TLC. You’ll need to take the same approach as when dealing with a poorly pet. When you bring your cat home, observe the following protocols:

  • Give her a warm, comfortable, and quiet place to rest.
  • Provide food, water, and toys. Don’t worry if these are ignored. Refresh them where necessary.
  • Don’t force your cat to interact. Let her approach you for attention if she wants it.
  • Check her occasionally, and subtly look for any signs of problems. Pay particular attention to the site of the injection.

Most cats just need peace and quiet, and time to themselves, after vaccines. Within 48 hours, they will likely be acting as though nothing happened.

Are Vaccinations Essential for Cats?

This is a debate that will rage for as long as vaccines exist. Many people believe that vaccines are essential. Others claim that they are a moneymaking enterprise for the veterinary industry.

If the rabies vaccination is mandatory in your state, there is no way around this requirement. Your cat must have the shot and boosters as often as the law dictates.

The FVCRP vaccine is advisable in most cases, especially if your cat goes outside.

Respiratory conditions such as calicivirus and feline herpesvirus, are highly contagious. Panleukopenia is often fatal. If you can protect your pet from these illnesses, it’s best to do so.

Besides, many cat boarding houses insist on their intake being vaccinated against these conditions. If you’re planning a vacation and wish to use a kennel, you may need to vaccinate your cat.

The same also applies when traveling. If you wish to take your cat to a different country, some vaccinations are legally required.

Your cat will experience some side effects. For some pets, these will be minor. But for others, they will be significant. Some pet owners are unwilling to take this chance with their cat.

There is no right or wrong answer here. It depends on your point of view. Be aware that vaccines may save your cat’s life someday.

Vaccination is advisable if you live with multiple cats or your pet roams outdoors. There is no way of knowing what she’ll pick up from other animals.

There is one thing that really should be stressed, though. You need to make a decision based on what’s best for your cat. Put your views and wishes to one side where possible.

Vaccines can be expensive, and you may prefer a more holistic approach to healthcare. If this places your pet’s health at risk, it’s unfair to the cat in question. She is unable to make these decisions on her own behalf, so she relies on you.

Side Effects of Vaccinations for Senior Cats

The subject of vaccinations for older cats can be a difficult one. On the one hand, older cats have weaker immune systems. On the other, they’ll be hit harder by any side effects.

If your elderly cat has a chronic illness, then you should avoid vaccination. These treatments can aggravate problems with the heart and kidneys.

If your cat has tolerated vaccinations well in the past, there is no reason to deny her boosters. It’s advisable if your cat roams outside. Indoor cats have completely different requirements.

Respiratory illnesses, which vaccinations protect against, can be lethal for senior cats. Also, any other disease can rapidly spread if the animal is not protected.

If you adopt an older cat, gather as much information as possible about her medical history. This will be indispensable in judging whether your cat can safely tolerate vaccinations.

If you adopt from a shelter, ask if vaccinations have already been administered. This is often the case in shared living arrangements. Do not subject your cat to unnecessary vaccinations.

Cats can, and likely will, react to vaccines. This is an unavoidable side effect of the process. These reactions should not be severe, and most cats bounce back quickly.

If you have any concerns over your cat’s safety, speak to a professional before she is vaccinated. In most cases, the risks are outweighed by the safety that vaccines provide.