Kittens are adorable, playful, energetic, and cuddly, and also a big responsibility. As a conscientious kitten owner, you must ensure your feline friend is properly vaccinated. Our Creature Comforts Veterinary Service team knows adopting a kitten can be overwhelming, so we provide answers to frequently asked questions about kitten vaccines to help you understand the importance of this healthcare requirement.

Question: What are kitten vaccines?

Answer: Vaccines help prepare your kitten’s immune system to fight infection by triggering an immune response. This allows their immune system to recognize and remember the infectious agent without causing the actual disease. Vaccines undergo intense safety and efficacy testing before they are approved for use in cats.

Feline vaccines are classified as follows:

  • Modified live — These vaccines contain weakened forms of the pathogen that causes the targeted disease. Because the microorganisms are weakened, they typically don’t cause illness in healthy cats, but they can replicate for a short time after administration to provoke a good immune response.
  • Killed or inactivated — Inactivated vaccines contain killed pathogens that can’t cause disease. These vaccines usually require multiple doses or boosters to maintain immunity.
  • Recombinant — These vaccines combine a part of the pathogen (e.g., the genes responsible for the proteins that trigger an immune response) that is inserted in other cells to create an immune response.

Q: What vaccines does my kitten need?

A: Core vaccines are the vaccines recommended for all kittens and cats, which include:

  • Rabies — Rabies is a viral disease that is most commonly transmitted through an infected animal’s bite. Pets as well as wildlife can carry the deadly disease, whose signs include behavioral changes, irritability, aggression, excessive drooling, and paralysis. Pennsylvania law mandates that all cats be vaccinated against rabies by 12 weeks of age.
  • Panleukopenia — Also called feline distemper, this is a highly contagious disease caused by the feline parvovirus. The virus is shed in an infected cat’s urine, feces, and nasal secretions, and infection occurs when a kitten encounters these substances or the fleas from an infected cat. Signs include lethargy, inappetence, high fever, vomiting, severe diarrhea, and nasal discharge.
  • Feline viral rhinotracheitis — This disease is caused by feline herpesvirus type 1 (FHV-1). The virus is shed in an infected cat’s saliva, nasal discharge, and ocular secretions, and infection occurs when a kitten directly contacts an infected cat or contaminated objects. Signs include sneezing, nasal congestion, eye inflammation, lethargy, and inappetence. Once infected, the virus remains in the cat’s body and can be reactivated if the cat is stressed or ill.
  • Calicivirus — Feline calicivirus causes upper respiratory infections and oral disease in kittens and cats. Transmission occurs through direct contact with an infected cat or objects contaminated with an infected cat’s saliva, nasal discharge, or ocular secretions. Signs include sneezing, nasal congestion, nasal and ocular discharge, and ulcers on the tongue, hard palate, gums, lips, or nose. 
  • Feline leukemia (FeLV) — The feline leukemia vaccine is considered a core vaccine for kittens and optional for adult cats. This viral infection is transmitted through close contact (e.g., mating, mutual grooming, sharing food bowls, and litter trays) with an infected cat. The virus attacks the cat’s immune system and blood-producing tissues, which become too weak to fight infection. Common signs include weight loss, unkempt appearance, fever, inflamed gums and mouth, enlarged lymph nodes, diarrhea, and chronic skin, eye, respiratory, and urinary tract infections. FeLV is the most common cause of cancer in cats.

Q: Does my kitten need other vaccines?

A: Depending on your cat’s lifestyle and disease risk, we may recommend optional or non-core vaccines, such as:

  • Bordetella — Bordetella is a bacterial disease that causes respiratory infections in cats. If you show or board your cat, we may recommend this vaccine.
  • Chlamydia — Chlamydia is a bacterial disease that causes ocular inflammation and may involve the upper respiratory tract and lungs. Your kitten may need this vaccine if they often contact other cats.

Q: When should my kitten be vaccinated?

A: Kitten vaccines for panleukopenia, FHV-1, and calicivirus should begin at 6 to 8 weeks of age, followed by boosters every three to four weeks until they are 16 to 18 weeks old. Kittens should receive a FeLV vaccine at 8 weeks of age and a booster three to four weeks after the initial dose. The rabies vaccine is given at 8 weeks of age and boosters are administered every one to three years. 

Q: Why does my kitten need so many vaccines?

A: Newborn kittens receive temporary immunity through their mother’s first milk (i.e., colostrum) that protects them for the first few weeks of life while their immune system starts to mature. This immunity starts to fade around 8 to 12 weeks of age, but when present, the antibodies prevent the immune system from responding appropriately to vaccines. Since we can’t know exactly when a kitten will lose the passive immunity and be ready for vaccines, we give a series of vaccines at specific intervals to help stimulate the kitten’s active immunity.

Don’t let your precious kitten go unprotected. Contact our Creature Comforts Veterinary Service team to schedule your tiny feline’s vaccine appointment.