The American Association of Feline Practitioners released new guidelines for vaccinating your cat in last month's Journal of Veterinary Medicine and Surgery. In response to growing concern and criticism about vaccine-related cancers, and other reactions, the new guidelines include optimal locations on a cat's body where vaccines should be given. These locations are the front paw, below the elbow, for respiratory vaccines; rabies vaccines should go into the right rear paw below the knee, and the feline leukemia vaccine (FeLV) should go into the left rear paw, also below the knee.
The report also says that vaccines should no longer be given between the shoulder blades or in the hips or upper legs, all of which have been popular places to give vaccines in the past.
The purpose of this recommendation is to make it easier to remove tumors that may develop at the vaccine site. The cancers that have been known to develop tend to follow rabies or FeLV vaccines, and they tend to be invasive and likely to spread. According to PetMD, while the actual cause of the cancer is unknown, it's believed that inflammation at the site of injection may play a role in the cancer's development.
A cat's risk for developing a sarcoma goes up as she receives multiple vaccines in the same area; cats receiving two vaccines at the same site are 127% more likely to develop a sarcoma, for instance. The highest-risk area appears to be between the shoulder blades.
Whether you need to take your cat in for shots, and what shots she should get, depends heavily on the type of lifestyle she has. An indoor/outdoor, or outdoor-only, cat will require more vaccines than an indoor-only cat, because being outside means she may come into contact with cats and other animals carrying infectious diseases. It may also be dictated by law; many areas require rabies vaccines to cut down on the incidence of the disease and protect both pets and people from infected animals.
It's important to discuss your cat's lifestyle with your vet so the proper vaccine regimen can be prescribed. It's also important to keep an eye on the vaccination site for several days afterward to ensure that swelling and redness don't persist, and to ensure that lesions don't develop, because these are all signs of a reaction to the vaccine. If you see anything concerning, contact your vet immediately.