These Annual Vaccines Keep Indoor Cats Healthy and Protected


Indoor cats still require regular vaccinations, even though they do not go outside. There are core vaccines that all cats should receive to protect against common and potentially deadly feline diseases. The main vaccines indoor cats need yearly are rabies, panleukopenia (feline distemper), rhinotracheitis, and calicivirus. These core vaccines protect cats against rabies, a fatal neurological disease, as well as panleukopenia, herpesvirus, and calicivirus – which can cause severe illness. This article will outline the key vaccines indoor cats require and provide the recommended schedule.

Core Vaccines

There are four core vaccines that all cats should receive to protect against serious and potentially fatal diseases: rabies, panleukopenia, rhinotracheitis, and calicivirus according to guidelines from The American Animal Hospital Association (AAHA) and the American Association of Feline Practitioners (AAFP).

Rabies is a fatal viral disease that can affect the central nervous system of mammals, including cats, and is transmissible to humans. The rabies vaccine is considered a core vaccine because rabies is legally mandated for cats in most jurisdictions. The killed virus rabies vaccine provides protection against the rabies virus and is safe and effective.

Panleukopenia, also known as feline distemper, is a contagious and serious disease caused by the feline parvovirus that can cause severe vomiting, diarrhea, and dehydration. The modified live virus panleukopenia vaccine provides effective protection against this potentially fatal virus.

Feline viral rhinotracheitis is an upper respiratory infection caused by the feline herpesvirus-1 (FHV-1). Its symptoms include sneezing, runny nose/eyes, fever, lethargy. The modified live virus FHV-1 vaccine protects cats against this common and highly contagious virus.

Feline calicivirus is another upper respiratory illness that causes oral ulcers, limping, and fever. The modified live virus FCV vaccine provides effective protection against disease caused by this virus.

Together, these core vaccines protect cats against the most common and serious feline illnesses and are considered essential by veterinary experts. Kittens should receive a series of boosters for the core vaccines starting at 6-8 weeks of age, with boosters continuing until 16-20 weeks of age, after which annual boosters are recommended.


Rabies is a fatal viral disease that affects the central nervous system of mammals, including cats (Table of State Rabies Laws Concerning Cats). It is spread through the saliva of infected animals, usually via bites. Rabies attacks the brain and spinal cord, causing inflammation of the brain and resulting in symptoms like abnormal behavior, aggression, excessive drooling, paralysis, and death (Rabies Laws by State).

Due to the fatal nature of rabies, vaccination laws exist in most states. Currently, rabies vaccination is required for cats in 34 states (Rabies laws: What you need to know). Cat owners can face fines and other penalties for failing to vaccinate their pets. The rabies vaccine is considered a “core” vaccine for cats and should be administered regularly starting around 12-16 weeks of age.


Panleukopenia, also known as feline distemper, is a highly contagious and potentially fatal viral disease caused by the feline parvovirus (Feline panleukopenia – AVMA). The virus attacks and destroys white blood cells, leaving the cat susceptible to secondary infections. It has a mortality rate of 10-90% if left untreated (Feline Panleukopenia – VCA Animal Hospitals).

Panleukopenia is spread through direct contact with infected bodily secretions, especially feces and vomit. The virus can survive in the environment for up to a year and is resistant to many disinfectants. All cats are susceptible, but kittens and unvaccinated cats are at the highest risk (Feline Panleukopenia – Merck Veterinary Manual).


Rhinotracheitis is caused by feline herpesvirus type-1 (FHV-1), also known as feline viral rhinotracheitis (FVR). It is one of the most common upper respiratory infections in cats. FHV-1 is extremely contagious and spreads through direct contact, shared food bowls, and respiratory secretions (Animal Emergency Care).

Symptoms of FHV-1 include sneezing, nasal discharge, eyes discharge, fever, reduced appetite, and lethargy (Merck Veterinary Manual). It can also lead to corneal ulcers and eosinophilic keratitis in the eyes. The infection is lifelong due to the virus remaining dormant in nerve cells. Stress can trigger recurrences of symptoms throughout the cat’s life.

There is no cure for FHV-1 but symptoms can be managed through supportive care. Antiviral medications may be prescribed to reduce viral shedding. Severe cases may require hospitalization and fluids. Vaccination is important to prevent infection and reduce disease severity.


Calicivirus is a highly contagious virus that causes upper respiratory infections and oral disease in cats. It is one of the most common causes of respiratory illness in cats. Calicivirus is spread through direct contact with infected saliva, nasal secretions, or eye discharges. It can also spread through contaminated surfaces like food bowls. Cats infected with calicivirus typically develop symptoms like fever, sneezing, nasal discharge, ulcers on the tongue, and excess salivation. In some cases, calicivirus can progress to severe pneumonia. The virus infects and damages the cells lining the upper respiratory tract, oral cavity, and lungs of cats (Feline CaliciVirus (FCV) Infection).

While most cats recover from calicivirus infections, some cats can become chronic carriers of the virus. In carrier cats, the virus persists long-term in the oral cavity and is shed continuously. Carriers tend not to show clinical signs but can still spread the infection to other cats. Vaccination is important to prevent outbreaks of calicivirus especially in multi-cat households and shelters where the virus spreads rapidly (Feline Calicivirus).

Non-Core Vaccines

Non-core vaccines are those that are recommended based on a cat’s risk and lifestyle factors. These include:

Feline Leukemia Virus (FeLV) – The FeLV vaccine may be recommended for cats with outdoor access who are at higher risk of exposure. FeLV is a retrovirus that suppresses the immune system.

Feline Immunodeficiency Virus (FIV) – The FIV vaccine may be recommended for free-roaming cats who fight frequently. FIV is a lentivirus that weakens the immune system.

Chlamydophila felis – This bacteria causes conjunctivitis, especially in crowded conditions like shelters. The vaccine may help reduce outbreaks.

Bordetella bronchiseptica – This bacteria causes upper respiratory infections. The vaccine may be recommended for young cats in shelters/breeding environments.

Discuss these non-core vaccine options with your veterinarian, as they can evaluate your cat’s risk factors and lifestyle to determine which are recommended.

Vaccine Schedule

The recommended vaccine schedule for cats depends on the cat’s age and whether they are a kitten or an adult cat. According to the 2020 AAHA/AAFP Feline Vaccination Guidelines, the recommended schedule is:

For kittens:

  • 6-8 weeks: FHV-1, FCV, FPV
  • 9-12 weeks: FHV-1, FCV, FPV, FeLV (if risk factors present)
  • 12-16 weeks: FHV-1, FCV, FPV, rabies

For adult cats:

  • 1 year after last kitten booster: FHV-1, FCV, FPV, rabies
  • Every 3 years thereafter: FHV-1, FCV, FPV, rabies

Adult cats with risk factors may need more frequent core vaccines, non-core vaccines, or booster doses as determined by a veterinarian.


While vaccines are important to protect cats from dangerous diseases, there can be some risks and side effects associated with vaccination. These may include:

Local reactions at the injection site like pain, swelling, and abscesses, though these are typically mild and resolve on their own (1). There can also be systemic reactions like lethargy, decreased appetite, and fever, but these usually don’t last more than a day or two (2).

More severe reactions are possible but quite rare. These include anaphylaxis and the development of fibrosarcomas, which are tumors believed to be associated with the vaccine adjuvants. However, a 2018 study estimated the risk of post-vaccination sarcoma at 1-2 cases per 10,000 cats vaccinated (3).

To minimize risks, current vaccination guidelines recommend the rabies vaccine no more frequently than every 3 years in adult cats. Other core vaccines may only need boostering every 3 years as well (1). It’s also important to only administer vaccines deemed necessary for the specific cat based on lifestyle and risk factors.

Overall, while some side effects can occur, the well-documented benefits of vaccination in preventing life-threatening diseases generally far outweigh the small risks involved.



In conclusion, keeping indoor cats up-to-date on their core vaccines—including rabies, panleukopenia, rhinotracheitis, and calicivirus—is crucial for protecting their health and preventing dangerous diseases. While non-core vaccines may provide additional protection in some cases, the core vaccines should form the foundation of any indoor cat’s vaccine protocol according to the recommended schedule. Kittens in particular require a series of vaccinations in their first year of life to establish immunity. Beyond protecting your cat, adhering to vaccine guidelines also maintains public health and prevents the spread of contagious illnesses. Consult with your veterinarian to ensure your cat receives all the necessary vaccines at the appropriate times. Though the initial shots and periodic boosters represent an investment, vaccinating your cat is one of the most vital steps you can take to keep them healthy and safe from preventable diseases.

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