Do Cats Feel Under the Weather After Fvrcp Vaccine? The Truth Revealed


The FVRCP vaccine is an important combination vaccine given to cats to protect against three highly contagious and potentially deadly feline viruses: feline viral rhinotracheitis, calicivirus, and panleukopenia virus. While vaccines play a crucial role in preventing disease, some cats may experience mild side effects afterwards, leading owners to wonder if their cat is feeling temporarily unwell. In this article, we’ll take a closer look at the FVRCP vaccine, its potential side effects, and examine evidence on whether cats actually feel bad or understand the connection between vaccination and feeling under the weather.

What is the Fvrcp Vaccine?

The Fvrcp vaccine, also known as the feline viral rhinotracheitis-calicivirus-panleukopenia vaccine, protects cats against three highly contagious viral diseases: feline viral rhinotracheitis (FVR), feline calicivirus (FCV), and feline panleukopenia (FPV). It is considered a core vaccine for cats and is recommended for all kittens as well as adult cats by veterinary organizations.

FVR is an upper respiratory infection caused by feline herpesvirus type 1. Symptoms include fever, lethargy, loss of appetite, sneezing, and discharge from the nose and eyes. FCV also causes upper respiratory infections with similar symptoms plus oral ulcers. FPV is a highly contagious parvovirus infection that attacks the intestinal tract leading to vomiting, bloody diarrhea, and rapid dehydration.

The Fvrcp vaccine contains modified live viruses to stimulate an immune response in cats without causing disease. When given to kittens, two doses are administered 3-4 weeks apart starting as early as 6 weeks of age, then boosters every 1-3 years depending on risk factors. It is safe, effective, and critical to protecting cats against these viral threats.

Common Side Effects

The most common side effects of the Fvrcp vaccine in cats are:

While these side effects are usually mild and resolve within a couple days, it’s important to monitor your cat after vaccination and contact your vet if any symptoms seem severe or persistent.

Why Do Side Effects Occur?

Vaccines work by stimulating the immune system to produce antibodies that protect against disease. This process essentially “trains” the immune system to recognize and fight off viruses or bacteria in the future. When a vaccine is administered, the weakened or inactive form of the virus or bacteria tricks the body into thinking it’s the real thing. This triggers the immune system to produce T-lymphocytes and B-lymphocytes – white blood cells that detect and destroy the foreign invaders. The lymphocytes also remember the specific antigens, creating immunity against future infection (CDC).

As the immune system fires up, it releases chemical messengers called cytokines to help coordinate the response. This process causes inflammation, which leads to common vaccine side effects like fever, headache, fatigue and muscle aches. These inflammatory effects are a sign that the immune system is responding as expected. While unpleasant, they are only temporary and much less risky than developing the actual disease. The vaccine ingredients and preservatives may also contribute to certain reactions. Overall, side effects mean the vaccine is stimulating the intended protective immune response that will provide long-term benefits (History of Vaccines).

Do Cats Understand They Feel Bad?

When cats experience side effects after a vaccine, it’s natural for owners to wonder if their pet understands why they are feeling unwell. Research indicates that cats do have some capacity for understanding cause and effect. A 2016 study by researchers at Kyoto University found that cats understand basic physics and object permanence. The researchers concluded that cats “associate cause and effect relationships between their owners’ actions, sounds made by objects, and the movement of objects” (source).

This means cats likely understand action and consequence on a basic level. When a cat receives a vaccine injection and then proceeds to feel lethargic, nauseous, or sore, they may associate these effects with getting the shot. However, their understanding is limited. Cats do not comprehend preventative medicine or have awareness of disease threats requiring vaccination. So while your cat may recognize feeling bad followed the vet visit, they do not grasp the medical necessity behind it.

You can help your cat cope after vaccination by providing extra affection and care. Keep their environment calm and comfortable. With time they will recover and not associate the unpleasant feelings with you. It’s important not to delay or skip recommended vaccines out of worry for side effects. The dangers posed by infectious diseases far outweigh potential short-term vaccine reactions. Trust your vet to advise what’s best for your cat’s health and wellbeing.

Monitoring Your Cat Afterwards

After your cat receives the FVRCP vaccine, it’s important to monitor them for any potential side effects. According to the American Animal Hospital Association’s 2020 Feline Vaccination Guidelines, veterinarians recommend using the “3-2-1” rule for monitoring the vaccination site:

– Check the injection site 3 times during the first 30 minutes post-vaccination.[1]

– Continue monitoring the site 2 times per day for the first 3 days.

– Call your veterinarian if any swelling or lumps persist for more than 1 day post-vaccination.

Some signs to watch for include redness, swelling, pain, or discharge at the injection site. Other potential side effects like fever, lethargy, decreased appetite, and nasal/eye discharge may indicate an adverse reaction. While rare, contact your vet immediately if your cat experiences vomiting, diarrhea, difficulty breathing, collapse, or seizures. Provide details on when symptoms started and how long they have persisted.

Closely monitoring your cat and quickly reporting any concerning symptoms allows your vet to provide timely treatment if an adverse reaction occurs. Have your vet’s emergency contact information handy just in case. With proper post-vaccination monitoring, you can help keep your cat healthy and safe.

Reducing Stress

Getting vaccinated can be stressful for cats. Some ways to help reduce a cat’s stress before and during vaccinations include:

Using synthetic feline facial pheromones like Feliway can help relax cats before vet visits. Pheromone diffusers or sprays should be used at home and in the carrier 30-60 minutes before the appointment.

Allow the cat to get comfortable in the exam room before administering vaccines by giving them time to explore. Provide treats to help create positive associations.

Avoid cold surfaces by ensuring exam tables and floors are warm. Place a non-slip mat on exam tables.

Use distraction techniques during the appointment such as food puzzles, catnip toys, or gentle strokes. These can shift the cat’s focus away from the vaccines.

Administer vaccines quickly and efficiently to minimize restraint time. Allow the cat to sit or lay in their preferred position.

Schedule appointments at less busy times to avoid long wait times. Request that exam rooms be prepped ahead of time.

Consider anti-anxiety medication prescribed by your vet for extremely anxious or fearful cats.

Reward and soothe the cat with treats, praise, or pets after vaccines are administered.

Alternative Vaccine Schedules

Some pet owners choose to follow an alternative vaccine schedule that spreads out their cat’s shots over a longer period of time. The goal is to reduce the chance of side effects by not overwhelming the immune system all at once. According to the American Animal Hospital Association (AAHA), an alternate schedule may separate the distemper/upper respiratory combination and rabies vaccines by 2-4 weeks (AAHA Guidelines,

Potential benefits of an alternate schedule include:
– Lower risk of vaccine reactions
– Less stress on the immune system
– More time for recovery between vaccines

However, there are also some potential downsides:
– Requires more vet visits and expense

– Delays full protection from diseases
– Risk of forgetting a dose
– Less vet recommended

Pet owners should consult with their veterinarian to determine if an alternative schedule makes sense for their cat based on health history and lifestyle. The pros and cons should be weighed carefully. Kittens may benefit most from spreading out initial vaccine doses. For adult cats, the core vaccines are generally only given every 3 years, so side effects are less likely to be an issue.

The Importance of Vaccines

Despite the potential for mild side effects, vaccines provide critical protection for cats against dangerous and sometimes fatal diseases like panleukopenia, calicivirus, herpesvirus, rabies, and feline leukemia (1). Vaccinating cats has been instrumental in controlling these infectious diseases and saving countless lives. According to Cornell University, “Vaccination is the foundation of disease prevention in cats” (2). Without proper vaccination protocols, we could see resurgences of viruses that used to kill large numbers of cats before vaccines were available. While vaccine reactions can occur and be unpleasant for a short time, the alternative of leaving cats vulnerable to harmful illnesses is far worse. By vaccinating cats on schedule, owners can ensure strong immunity against contagious diseases that could otherwise threaten their pet’s health and even their life. The benefits far outweigh the potential risks.



While the potential side effects from the FVRCP vaccine may seem concerning, it’s important to remember that they are usually mild and temporary. Vaccinating your cat against these dangerous viruses protects their long-term health and wellbeing. The momentary discomfort of a fever, lethargy or localized swelling is minor compared to the suffering caused by deadly feline distemper or calicivirus.

Follow your veterinarian’s guidance on managing potential vaccine reactions. Monitor your cat closely in the days following vaccination and call your vet if any concerning symptoms develop. Some cats may need an alternative vaccination schedule to reduce stress and side effects. With proper care and precaution, you can give your cat the best protection against disease while minimizing vaccine reactions.

In the end, the proven benefits of routine FVRCP vaccination far outweigh the small risk of side effects. While no medical treatment is completely without risk, vaccines remain the safest and most effective way to protect your cat’s health. Trust your vet to make the right recommendations so your cat stays happy and healthy for years to come.

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