Vaccinations (immunizations, "shots") have saved the lives of millions of cats. Before the days of effective vaccines, cats routinely died from panleukopenia ("feline distemper") and complications of upper respiratory (herpesvirus, calicivirus) infections. Newer vaccines are available to protect against feline leukemia virus infection, feline infectious peritonitis virus and other infections (chlamydia, feline bordetella, ringworm). Current vaccination programs protect our cats (and us) from the threat of rabies.
As pets age, questions about vaccinations arise. Common questions are which vaccine does my senior cat need and how often should he be vaccinated. Unfortunately, the absolute answers to these questions are not known but there are several recommendations. The major concern about repeated vaccinations in cats is the issue of feline vaccine-associated sarcoma. This is a cancer that develops near the vaccination site. The incidence varies widely, from as high as one in 1,000 cats to as low as one in 10,000 cats.
Despite the well-known benefits of vaccination, the practice of vaccinating senior cats annually is controversial. Some veterinarians believe that annual revaccination is a critical part of preventative health care. Some research indicates that the immune system of older animals is not as effective as younger animals. This suggests that older cats may be more susceptible to diseases and therefore require annual vaccinations. Others suggest that there is little scientific information to suggest that annual revaccination of older cats is necessary for some diseases because immunity to many viruses probably persists for the life of the animal. For this reason, many veterinarians do not think that annual vaccination is worth the risk of allergic reaction, vaccine-induced sarcoma or immune diseases.
The one thing that many veterinarians agree on is that cats should only be vaccinated against those diseases for which they are susceptible. For example, if your cat is indoors and not exposed to stray cats or new family feline additions, vaccinating for feline leukemia and feline infectious peritonitis is not recommended. If your cat is at risk for feline infectious peritonitis, many feline veterinarians recommend that a blood test be performed to see if the cat has been exposed to coronavirus. If the coronavirus titer in the cat is elevated (indicating exposure), the vaccination will not be effective and should be avoided.
Rabies should be given based on local laws. In some areas, Rabies vaccination must be given every year. In other areas, local law allows vaccination to be given every three years. Recommendations
The foremost recommendation is to discuss the vaccination program with your veterinarian. Don't hesitate to ask questions about the pros and cons of vaccinations.
For cats older than 8 to 10 years of age, annual revaccination should be discussed with your veterinarian. There is no nationally accepted standard at this time. Many veterinarians stagger booster immunizations over a number of years. Typical boosters include vaccines against feline panleukopenia ("distemper") and the upper respiratory viruses (herpesvirus, calicivirus).
If the risk of feline leukemia virus exposure is significant (out-of-doors cats), the leukemia virus vaccine sequence should be administered. If the cat is not at risk, many veterinarians do not recommend the feline leukemia virus vaccination. Other vaccines are given on a case-by-case basis. Some veterinarians use traditional "shots" for vaccination while others use a combination of injections and intra-nasal vaccines. The rabies vaccines should be given as required by local laws.
For more information on caring for your senior pet, please read Geriatric Cat Care.